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Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin

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  • Peter Walker
    Hello you suffered from low flow as the hose was WAYYYY too big The step up and down also created a  turbulent zone at both ends of the hose Peter ... From:
    Message 1 of 19 , Feb 18, 2013
      Hello
       you suffered from low flow as the hose was WAYYYY too big The step up and down also created a  turbulent zone at both ends of the hose 
      Peter

      --- On Tue, 2/19/13, woody king <woodyking2001@...> wrote:

      From: woody king <woodyking2001@...>
      Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
      To: Small4-strokeEngines@yahoogroups.com
      Date: Tuesday, February 19, 2013, 1:59 AM

       

      My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

      --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

      From: Kev A <kevin@...>
      Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
      To: Small4-strokeEngines@yahoogroups.com
      Date: Monday, February 18, 2013, 9:29 AM

       
      Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

      This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

      "Carb is standard and mounted on the motor mount.
      Float type carbs are sensitive for vibrations. This system reduces
      vibrations from motor."

      What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

      His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

      What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

      Kev

    • Kev A
      Sounds right; 2.25 diameter is almost a plenum. more like 1.25 on mine. I d envisaged long but no change in section The Luciole has very long inlet tubes to
      Message 2 of 19 , Feb 18, 2013
        Sounds right; 2.25 diameter is almost a plenum. more like 1.25" on mine.

        I'd envisaged long but no change in section

        The Luciole has very long inlet tubes to run down to a carb set under the crankcase, maybe Columban thinks long inlet tracts are a good thing too?

        Great idea to use exhaust tubing, easy to get the bends and heatproof too

        Kev

        --- In Small4-strokeEngines@yahoogroups.com, Peter Walker <peterwalker58@...> wrote:
        >
        > Hello you suffered from low flow as the hose was WAYYYY too big The step up and down also created a  turbulent zone at both ends of the hose Peter
        >
        > --- On Tue, 2/19/13, woody king <woodyking2001@...> wrote:
        >
        > From: woody king <woodyking2001@...>
        > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
        > To: Small4-strokeEngines@yahoogroups.com
        > Date: Tuesday, February 19, 2013, 1:59 AM

        > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
        >
        > --- On Mon, 2/18/13, Kev A <kevin@...> wrote:
        >
        >
        > From: Kev A <kevin@...>
        > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
        > To: Small4-strokeEngines@yahoogroups.com
        > Date: Monday, February 18, 2013, 9:29 AM
        >
        >
        >
        >  
        >
        > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
        >
        > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
        >
        > "Carb is standard and mounted on the motor mount.
        > Float type carbs are sensitive for vibrations. This system reduces
        > vibrations from motor."
        >
        > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
        >
        > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
        >
        > What do you guys think? Fairly easy to
        > do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
        >
        > Kev
        >
      • Peter Walker
        Hello For 2nd order harmonics you need 26 from valve seat to carb It gives 7% increase from 3385 to 3800RPMPeter ... From: dagwodzz@bellsouth.net
        Message 3 of 19 , Feb 18, 2013
          Hello 
          For 2nd order harmonics you need 26" from valve seat to carb It gives 7% increase from 3385 to 3800RPM
          Peter
          --- On Tue, 2/19/13, dagwodzz@... <dagwodzz@...> wrote:

          From: dagwodzz@... <dagwodzz@...>
          Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
          To: Small4-strokeEngines@yahoogroups.com
          Date: Tuesday, February 19, 2013, 2:08 AM

           

          Woody, How long were the original intake?  
           
           
           
           
          -------Original Message-------
           
          Date: 2/18/2013 9:00:10 AM
          Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
           
           

          My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

          --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

          From: Kev A <kevin@...>
          Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
          To: Small4-strokeEngines@yahoogroups.com
          Date: Monday, February 18, 2013, 9:29 AM

           
          Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

          This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

          "Carb is standard and mounted on the motor mount.
          Float type carbs are sensitive for vibrations. This system reduces
          vibrations from motor."

          What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

          His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

          What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

          Kev

           

        • woody king
          It was on a Zenoah G50, the original intake was carb mounted directly to the intake manifold with a 2 piece of hose, like most Rotax engines. Maybe a 1/4 gap
          Message 4 of 19 , Feb 18, 2013
            It was on a Zenoah G50, the original intake was carb mounted directly to the intake manifold with a 2" piece of hose, like most Rotax engines. Maybe a 1/4" gap between them, very similiar to rotax. One thing of note, the zenoah mounts had nylon cord in them, like a car tire, whereas the rotax boots do not..... much better design from Japan than from Austria. The Zenoah boots last forever, we know how long rotax boots last.


            --- On Mon, 2/18/13, dagwodzz@... <dagwodzz@...> wrote:

            From: dagwodzz@... <dagwodzz@...>
            Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
            To: Small4-strokeEngines@yahoogroups.com
            Date: Monday, February 18, 2013, 10:08 AM

             
            Woody, How long were the original intake?  
             
             
             
             
            -------Original Message-------
             
            Date: 2/18/2013 9:00:10 AM
            Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
             
             
            My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

            --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

            From: Kev A <kevin@...>
            Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
            To: Small4-strokeEngines@yahoogroups.com
            Date: Monday, February 18, 2013, 9:29 AM

             
            Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

            This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

            "Carb is standard and mounted on the motor mount.
            Float type carbs are sensitive for vibrations. This system reduces
            vibrations from motor."

            What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

            His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

            What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

            Kev

             
          • woody king
            Also, I tried moving just the foam air filters back and leaving the carbs where they were, I wanted to get the air filters away from the carbs to reduce the
            Message 5 of 19 , Feb 18, 2013
              Also, I tried moving just the foam air filters back and leaving the carbs where they were, I wanted to get the air filters away from the carbs to reduce the oil spray saturating them from the back breath of a piston ported two stroke. I also lost big time on power, still using the large diameter hose, which I saw as none restricting. After all, many intakes have a lot of turns and diameter changes between the carbs and the air filters, and the carbs and intake valves. Look at the Chrysler slant 6 for example, with many different intake lengths yet a smooth even engine. Or so it seems... Maybe the Zenoah was just super sensitive. Been a few years.

              --- On Mon, 2/18/13, woody king <woodyking2001@...> wrote:

              From: woody king <woodyking2001@...>
              Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
              To: Small4-strokeEngines@yahoogroups.com
              Date: Monday, February 18, 2013, 9:10 PM

              It was on a Zenoah G50, the original intake was carb mounted directly to the intake manifold with a 2" piece of hose, like most Rotax engines. Maybe a 1/4" gap between them, very similiar to rotax. One thing of note, the zenoah mounts had nylon cord in them, like a car tire, whereas the rotax boots do not..... much better design from Japan than from Austria. The Zenoah boots last forever, we know how long rotax boots last.


              --- On Mon, 2/18/13, dagwodzz@... <dagwodzz@...> wrote:

              From: dagwodzz@... <dagwodzz@...>
              Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
              To: Small4-strokeEngines@yahoogroups.com
              Date: Monday, February 18, 2013, 10:08 AM

               
              Woody, How long were the original intake?  
               
               
               
               
              -------Original Message-------
               
              Date: 2/18/2013 9:00:10 AM
              Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
               
               
              My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

              --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

              From: Kev A <kevin@...>
              Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
              To: Small4-strokeEngines@yahoogroups.com
              Date: Monday, February 18, 2013, 9:29 AM

               
              Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

              This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

              "Carb is standard and mounted on the motor mount.
              Float type carbs are sensitive for vibrations. This system reduces
              vibrations from motor."

              What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

              His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

              What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

              Kev

               
            • woody king
              I figured that the flow was given time to smooth out over the distance,and with carb diameter and intake diameter unchanged, it would work. If anything, more
              Message 6 of 19 , Feb 18, 2013
                I figured that the flow was given time to smooth out over the distance,and with carb diameter and intake diameter unchanged, it would work. If anything, more time for fuel/air mix to get even..... The amount being drawn and the amount going through the carb would be the same as before, other than the "turbulance". I don't see any other possibility, so I suppose the turbulance was killing it. If a hose with a reduced inner diameter was used, to match the ID of the carb and intake throat, do  you think that would work??

                --- On Mon, 2/18/13, Peter Walker <peterwalker58@...> wrote:

                From: Peter Walker <peterwalker58@...>
                Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                To: Small4-strokeEngines@yahoogroups.com
                Date: Monday, February 18, 2013, 4:42 PM

                 
                Hello
                 you suffered from low flow as the hose was WAYYYY too big The step up and down also created a  turbulent zone at both ends of the hose 
                Peter

                --- On Tue, 2/19/13, woody king <woodyking2001@...> wrote:

                From: woody king <woodyking2001@...>
                Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                To: Small4-strokeEngines@yahoogroups.com
                Date: Tuesday, February 19, 2013, 1:59 AM

                 
                My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

                --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

                From: Kev A <kevin@...>
                Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                To: Small4-strokeEngines@yahoogroups.com
                Date: Monday, February 18, 2013, 9:29 AM

                 
                Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

                This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

                "Carb is standard and mounted on the motor mount.
                Float type carbs are sensitive for vibrations. This system reduces
                vibrations from motor."

                What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

                His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

                What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

                Kev

              • rv7charlie
                http://rogueperformance.com/UpperIntakeManifold.html#a One link to intake tuning theory. If you do some digging, you should find additional info that talks
                Message 7 of 19 , Feb 18, 2013
                  http://rogueperformance.com/UpperIntakeManifold.html#a

                  One link to intake tuning theory. If you do some digging, you should find additional info that talks about the need to keep air velocity up in the intake manifold. Going too big with the tubes slows the air dramatically, & it loses its inertia to drive past the valve into the cylinder. Conventional wisdom among tuners is low rpm (these engines qualify): small diameter & longer runners; high rpm: shorter, larger diameter. Even at 6-7000 rpm, that size runner sounds pretty big. A 200 hp rotary (@7500rpm) uses 2ea  1 1/4" tubes feeding each of the 2 rotors.

                  Charlie

                  On 02/18/2013 08:34 PM, woody king wrote:
                   

                  I figured that the flow was given time to smooth out over the distance,and with carb diameter and intake diameter unchanged, it would work. If anything, more time for fuel/air mix to get even..... The amount being drawn and the amount going through the carb would be the same as before, other than the "turbulance". I don't see any other possibility, so I suppose the turbulance was killing it. If a hose with a reduced inner diameter was used, to match the ID of the carb and intake throat, do  you think that would work??

                  --- On Mon, 2/18/13, Peter Walker <peterwalker58@...> wrote:

                  From: Peter Walker <peterwalker58@...>
                  Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                  To: Small4-strokeEngines@yahoogroups.com
                  Date: Monday, February 18, 2013, 4:42 PM

                   
                  Hello
                   you suffered from low flow as the hose was WAYYYY too big The step up and down also created a  turbulent zone at both ends of the hose 
                  Peter

                  --- On Tue, 2/19/13, woody king <woodyking2001@...> wrote:

                  From: woody king <woodyking2001@...>
                  Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                  To: Small4-strokeEngines@yahoogroups.com
                  Date: Tuesday, February 19, 2013, 1:59 AM

                   
                  My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

                  --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

                  From: Kev A <kevin@...>
                  Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                  To: Small4-strokeEngines@yahoogroups.com
                  Date: Monday, February 18, 2013, 9:29 AM

                   
                  Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

                  This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

                  "Carb is standard and mounted on the motor mount.
                  Float type carbs are sensitive for vibrations. This system reduces
                  vibrations from motor."

                  What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

                  His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

                  What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

                  Kev


                • Kev A
                  That s terrific Peter, any chance of the numbers for a motor doing 4,300 rpm cruise, 4,700 full power please? Thanks Kev
                  Message 8 of 19 , Feb 18, 2013
                    That's terrific Peter, any chance of the numbers for a motor doing 4,300 rpm cruise, 4,700 full power please?

                    Thanks

                    Kev

                    --- In Small4-strokeEngines@yahoogroups.com, Peter Walker <peterwalker58@...> wrote:
                    >
                    > Hello For 2nd order harmonics you need 26" from valve seat to carb It gives 7% increase from 3385 to 3800RPMPeter
                    > --- On Tue, 2/19/13, dagwodzz@... <dagwodzz@...> wrote:
                    >
                    > From: dagwodzz@... <dagwodzz@...>
                    > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                    > To: Small4-strokeEngines@yahoogroups.com
                    > Date: Tuesday, February 19, 2013, 2:08 AM
                    >
                    >
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                    > Woody, How long were the original intake?  
                    >  
                    >  
                    >
                    >  
                    >  
                    >
                    > -------Original Message-------
                    >  
                    >
                    > From: woody king
                    > Date: 2/18/2013 9:00:10 AM
                    > To: Small4-strokeEngines@yahoogroups.com
                    > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                    >   
                    >
                    >
                    >
                    >
                    >
                    > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
                    >
                    > --- On Mon, 2/18/13, Kev A <kevin@...> wrote:
                    >
                    >
                    > From: Kev A <kevin@...>
                    > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                    > To: Small4-strokeEngines@yahoogroups.com
                    > Date: Monday, February 18, 2013, 9:29 AM
                    >
                    >
                    >
                    >  
                    >
                    > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
                    >
                    > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
                    >
                    > "Carb is standard and mounted on the motor mount.
                    > Float type carbs are sensitive for vibrations. This system reduces
                    > vibrations from motor."
                    >
                    > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
                    >
                    > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
                    >
                    > What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
                    >
                    > Kev
                    >
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                    >  
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                  • Peter Walker
                    Hello KevinInput length is 29 inches for 2nd harmonic, RPM range is from 4051 to 4916 with a pulse strength of 10 percentInput length is 21 inchesFor 3rd
                    Message 9 of 19 , Feb 19, 2013

                      Hello Kevin
                      Input length is 29 inches for 2nd harmonic, RPM range is from 4051 to 4916 with a pulse strength of 10 percent
                      Input length is 21 inchesFor 3rd harmonic, RPM range is from 4203 to 4804 with a pulse strength of 7 percent
                      If you want to build a simple cheap dyno for testing i can help A truck flywheel a microphone and a simple program...
                      Peter


                      --- On Tue, 2/19/13, Kev A <kevin@...> wrote:

                      From: Kev A <kevin@...>
                      Subject: [Small4-strokeEngines] Re: Hoses for inlets on any V-Twin
                      To: Small4-strokeEngines@yahoogroups.com
                      Date: Tuesday, February 19, 2013, 6:49 PM

                       

                      That's terrific Peter, any chance of the numbers for a motor doing 4,300 rpm cruise, 4,700 full power please?

                      Thanks

                      Kev

                      --- In Small4-strokeEngines@yahoogroups.com, Peter Walker wrote:
                      >
                      > Hello For 2nd order harmonics you need 26" from valve seat to carb It gives 7% increase from 3385 to 3800RPMPeter
                      > --- On Tue, 2/19/13, dagwodzz@... wrote:
                      >
                      > From: dagwodzz@...
                      > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                      > To: Small4-strokeEngines@yahoogroups.com
                      > Date: Tuesday, February 19, 2013, 2:08 AM
                      >
                      >
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                      >
                      > Woody, How long were the original intake?  
                      >  
                      >  
                      >
                      >  
                      >  
                      >
                      > -------Original Message-------
                      >  
                      >
                      > From: woody king
                      > Date: 2/18/2013 9:00:10 AM
                      > To: Small4-strokeEngines@yahoogroups.com
                      > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                      >   
                      >
                      >
                      >
                      >
                      >
                      > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
                      >
                      > --- On Mon, 2/18/13, Kev A wrote:
                      >
                      >
                      > From: Kev A
                      > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                      > To: Small4-strokeEngines@yahoogroups.com
                      > Date: Monday, February 18, 2013, 9:29 AM
                      >
                      >
                      >
                      >  
                      >
                      > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
                      >
                      > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
                      >
                      > "Carb is standard and mounted on the motor mount.
                      > Float type carbs are sensitive for vibrations. This system reduces
                      > vibrations from motor."
                      >
                      > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
                      >
                      > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
                      >
                      > What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
                      >
                      > Kev
                      >
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                    • woody king
                      Excellent thought, Charlie. I did look but didn t notice any collapse, and they were very stiff new thick hoses. BUT, you are so right. Except the major vaccum
                      Message 10 of 19 , Feb 23, 2013
                        Excellent thought, Charlie. I did look but didn't notice any collapse, and they were very stiff new thick hoses. BUT, you are so right. Except the major vaccum would be at idle, and my rpm/power loss was at full throttle. There the vaccum would be very low, but I did not consider the possibility you pointed out. Alot going on. Thanks for the input, I will add that to my "book" of things to remember.  Woody

                        --- On Mon, 2/18/13, RV7Charlie <mcsophie@...> wrote:

                        From: RV7Charlie <mcsophie@...>
                        Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                        To: "Small4-strokeEngines@yahoogroups.com" <Small4-strokeEngines@yahoogroups.com>
                        Date: Monday, February 18, 2013, 11:40 AM

                         
                        Could you see the hoses while running? Manifold vacuum has the potential to collapse a rubber hose, if it isn't designed to handle vacuum (like the spring in a radiator hose).

                        Sent from my iPhone

                        On Feb 18, 2013, at 8:59 AM, woody king <woodyking2001@...> wrote:

                         
                        My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody

                        --- On Mon, 2/18/13, Kev A <kevin@...> wrote:

                        From: Kev A <kevin@...>
                        Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                        To: Small4-strokeEngines@yahoogroups.com
                        Date: Monday, February 18, 2013, 9:29 AM

                         
                        Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.

                        This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-

                        "Carb is standard and mounted on the motor mount.
                        Float type carbs are sensitive for vibrations. This system reduces
                        vibrations from motor."

                        What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.

                        His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.

                        What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?

                        Kev

                      • Kev A
                        Wonder why Rotax and Robin etc. fit rubber carb mounts to kill vibes getting to the float needle assembly and messing up the mixture, and Briggs/Kohler/Generac
                        Message 11 of 19 , Feb 25, 2013
                          Wonder why Rotax and Robin etc. fit rubber carb mounts to kill vibes getting to the float needle assembly and messing up the mixture, and Briggs/Kohler/Generac don't?

                          A normal installation would see any of these bolted to something heavy iron and not too fussy about fuel burn, but as we hang ours on relatively flimsy lightweight structures, the V-Twin will vibrate much more.

                          Maybe that Czech feller had a point, and longer rubber hoses to a remote mounted carb are beneficial? Probably less chance of an in-flight fire too.

                          Cheers

                          Kev

                          --- In Small4-strokeEngines@yahoogroups.com, woody king <woodyking2001@...> wrote:
                          >
                          > Excellent thought, Charlie. I did look but didn't notice any collapse, and they were very stiff new thick hoses. BUT, you are so right. Except the major vaccum would be at idle, and my rpm/power loss was at full throttle. There the vaccum would be very low, but I did not consider the possibility you pointed out. Alot going on. Thanks for the input, I will add that to my "book" of things to remember.  Woody
                          >
                          > --- On Mon, 2/18/13, RV7Charlie <mcsophie@...> wrote:
                          >
                          >
                          > From: RV7Charlie <mcsophie@...>
                          > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                          > To: "Small4-strokeEngines@yahoogroups.com" <Small4-strokeEngines@yahoogroups.com>
                          > Date: Monday, February 18, 2013, 11:40 AM
                          >
                          >
                          >
                          >  
                          >
                          >
                          >
                          >
                          > Could you see the hoses while running? Manifold vacuum has the potential to collapse a rubber hose, if it isn't designed to handle vacuum (like the spring in a radiator hose).
                          >
                          > Sent from my iPhone
                          >
                          > On Feb 18, 2013, at 8:59 AM, woody king <woodyking2001@...> wrote:
                          >
                          >
                          >
                          >  
                          >
                          >
                          >
                          >
                          >
                          > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
                          >
                          > --- On Mon, 2/18/13, Kev A <kevin@...> wrote:
                          >
                          >
                          > From: Kev A <kevin@...>
                          > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                          > To: Small4-strokeEngines@yahoogroups.com
                          > Date: Monday, February 18, 2013, 9:29 AM
                          >
                          >
                          >
                          >  
                          >
                          > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
                          >
                          > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
                          >
                          > "Carb is standard and mounted on the motor mount.
                          > Float type carbs are sensitive for vibrations. This system reduces
                          > vibrations from motor."
                          >
                          > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
                          >
                          > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
                          >
                          > What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
                          >
                          > Kev
                          >
                        • dagwodzz@bellsouth.net
                          They will vibrate even more with rubber mounts. ... From: Kev A Date: 2/25/2013 3:23:54 PM To: Small4-strokeEngines@yahoogroups.com Subject:
                          Message 12 of 19 , Feb 25, 2013
                            They will vibrate even more with rubber mounts.   
                             
                             
                             
                             
                            -------Original Message-------
                             
                            From: Kev A
                            Date: 2/25/2013 3:23:54 PM
                            Subject: [Small4-strokeEngines] Re: Hoses for inlets on any V-Twin
                             
                             

                            Wonder why Rotax and Robin etc. fit rubber carb mounts to kill vibes getting to the float needle assembly and messing up the mixture, and Briggs/Kohler/Generac don't?

                            A normal installation would see any of these bolted to something heavy iron and not too fussy about fuel burn, but as we hang ours on relatively flimsy lightweight structures, the V-Twin will vibrate much more.

                            Maybe that Czech feller had a point, and longer rubber hoses to a remote mounted carb are beneficial? Probably less chance of an in-flight fire too.

                            Cheers

                            Kev

                            --- In Small4-strokeEngines@yahoogroups.com, woody king wrote:
                            >
                            > Excellent thought, Charlie. I did look but didn't notice any collapse, and they were very stiff new thick hoses. BUT, you are so right. Except the major vaccum would be at idle, and my rpm/power loss was at full throttle. There the vaccum would be very low, but I did not consider the possibility you pointed out. Alot going on. Thanks for the input, I will add that to my "book" of things to remember.  Woody
                            >
                            > --- On Mon, 2/18/13, RV7Charlie wrote:
                            >
                            >
                            > From: RV7Charlie
                            > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                            > To: "Small4-strokeEngines@yahoogroups.com" Small4-strokeEngines@yahoogroups.com>
                            > Date: Monday, February 18, 2013, 11:40 AM
                            >
                            >
                            >
                            >  
                            >
                            >
                            >
                            >
                            > Could you see the hoses while running? Manifold vacuum has the potential to collapse a rubber hose, if it isn't designed to handle vacuum (like the spring in a radiator hose).
                            >
                            > Sent from my iPhone
                            >
                            > On Feb 18, 2013, at 8:59 AM, woody king wrote:
                            >
                            >
                            >
                            >  
                            >
                            >
                            >
                            >
                            >
                            > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
                            >
                            > --- On Mon, 2/18/13, Kev A wrote:
                            >
                            >
                            > From: Kev A
                            > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                            > To: Small4-strokeEngines@yahoogroups.com
                            > Date: Monday, February 18, 2013, 9:29 AM
                            >
                            >
                            >
                            >  
                            >
                            > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
                            >
                            > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
                            >
                            > "Carb is standard and mounted on the motor mount.
                            > Float type carbs are sensitive for vibrations. This system reduces
                            > vibrations from motor."
                            >
                            > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
                            >
                            > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
                            >
                            > What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
                            >
                            > Kev
                            >

                             
                          • Peter Walker
                            Hello Simple to manufacture Cheap  Easy to fit  Expensive replacement And it is a bike norm so carbs to suit are easily available Peter
                            Message 13 of 19 , Feb 25, 2013
                              Hello

                              Simple to manufacture
                              Cheap 
                              Easy to fit 
                              Expensive replacement
                              And it is a bike norm so carbs to suit are easily available
                              Peter


                              From: invadermark4 <garrywarber@...>
                              To: Small4-strokeEngines@yahoogroups.com
                              Sent: Tuesday, February 26, 2013 6:07 AM
                              Subject: [Small4-strokeEngines] Re: Hoses for inlets on any V-Twin

                               
                              Two-stroke vibration would be at a much higher frequency, wouldn't it? And Rotax rubber mounts fail, a lot... Another thought, maybe they use diaphram carbs? I wouldn't know, as I really have to desire to learn about them.
                              Garry

                              --- In Small4-strokeEngines@yahoogroups.com, "Kev A" wrote:
                              >
                              > Wonder why Rotax and Robin etc. fit rubber carb mounts to kill vibes getting to the float needle assembly and messing up the mixture, and Briggs/Kohler/Generac don't?
                              >
                              > A normal installation would see any of these bolted to something heavy iron and not too fussy about fuel burn, but as we hang ours on relatively flimsy lightweight structures, the V-Twin will vibrate much more.
                              >
                              > Maybe that Czech feller had a point, and longer rubber hoses to a remote mounted carb are beneficial? Probably less chance of an in-flight fire too.
                              >
                              > Cheers
                              >
                              > Kev



                            • John
                              Long inlet pipes might actually be beneficial if they could be tuned like an exhaust is tuned. If I were to try this, I would certainly use thin wall metal
                              Message 14 of 19 , Feb 27, 2013
                                Long inlet pipes might actually be beneficial if they could be tuned like an exhaust is tuned. If I were to try this, I would certainly use thin wall metal tubes mounted reasonably firmly and use short rubber couplers to allow the vibration induced movement. It might take several "joints", each bending in an appropriate direction to allow all the necessary degrees of movement.

                                John

                                --- In Small4-strokeEngines@yahoogroups.com, "Kev A" <kevin@...> wrote:
                                >
                                > Wonder why Rotax and Robin etc. fit rubber carb mounts to kill vibes getting to the float needle assembly and messing up the mixture, and Briggs/Kohler/Generac don't?
                                >
                                > A normal installation would see any of these bolted to something heavy iron and not too fussy about fuel burn, but as we hang ours on relatively flimsy lightweight structures, the V-Twin will vibrate much more.
                                >
                                > Maybe that Czech feller had a point, and longer rubber hoses to a remote mounted carb are beneficial? Probably less chance of an in-flight fire too.
                                >
                                > Cheers
                                >
                                > Kev
                                >
                                > --- In Small4-strokeEngines@yahoogroups.com, woody king <woodyking2001@> wrote:
                                > >
                                > > Excellent thought, Charlie. I did look but didn't notice any collapse, and they were very stiff new thick hoses. BUT, you are so right. Except the major vaccum would be at idle, and my rpm/power loss was at full throttle. There the vaccum would be very low, but I did not consider the possibility you pointed out. Alot going on. Thanks for the input, I will add that to my "book" of things to remember.  Woody
                                > >
                                > > --- On Mon, 2/18/13, RV7Charlie <mcsophie@> wrote:
                                > >
                                > >
                                > > From: RV7Charlie <mcsophie@>
                                > > Subject: Re: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                                > > To: "Small4-strokeEngines@yahoogroups.com" <Small4-strokeEngines@yahoogroups.com>
                                > > Date: Monday, February 18, 2013, 11:40 AM
                                > >
                                > >
                                > >
                                > >  
                                > >
                                > >
                                > >
                                > >
                                > > Could you see the hoses while running? Manifold vacuum has the potential to collapse a rubber hose, if it isn't designed to handle vacuum (like the spring in a radiator hose).
                                > >
                                > > Sent from my iPhone
                                > >
                                > > On Feb 18, 2013, at 8:59 AM, woody king <woodyking2001@> wrote:
                                > >
                                > >
                                > >
                                > >  
                                > >
                                > >
                                > >
                                > >
                                > >
                                > > My experience, that I can't explain, was loss of power using hoses for intake runs. I was using straight 2.25 ID hose which was a great fit onto carb and intake, not restricting at all. Yet, I lost darn near 1000 rpm static. Hoses were about 14" long, with a long sweeping 20 degree overall turn. I went back and my power came back. I would not have thought this would make that much difference. I have used shorter similiar adapters on many things like motorcycles and hovercraft, and they seemed to work fine.     Woody
                                > >
                                > > --- On Mon, 2/18/13, Kev A <kevin@> wrote:
                                > >
                                > >
                                > > From: Kev A <kevin@>
                                > > Subject: [Small4-strokeEngines] Hoses for inlets on any V-Twin
                                > > To: Small4-strokeEngines@yahoogroups.com
                                > > Date: Monday, February 18, 2013, 9:29 AM
                                > >
                                > >
                                > >
                                > >  
                                > >
                                > > Juraj Tinka, a czech sport pilot was exchanging useful info with Arif, in Far East Asia, on his V-Twin mounted in a little sports fixed wing aircraft; Arif kindly copied me in.
                                > >
                                > > This was a Vanguard B&S but one idea he had that applies to any engine is in one of the emails:-
                                > >
                                > > "Carb is standard and mounted on the motor mount.
                                > > Float type carbs are sensitive for vibrations. This system reduces
                                > > vibrations from motor."
                                > >
                                > > What Juraj showed in the photos was two steel 'U' bend tubes on the heads, running back into long rubber auto hoses to a carburator fitted to the bulkhead.
                                > >
                                > > His rig was prop mounted flywheel side, I guess if prop mounted PTO side (on a redrive or taper shaft) on a tractor rig the inlet tubes would be easy, running straight back off the heads into a flange on a carb 12-18" behind the motor. Heat would need watching as the head heat might cook the rubber tubes.
                                > >
                                > > What do you guys think? Fairly easy to do by rigging a pair of adapter nbends off the top of the stock manifold, longer inlet tracts might give better power too?
                                > >
                                > > Kev
                                > >
                                >
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