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Correct cam chain installation

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  • Samuel Crider
    Greeting, I just stripped the ol gal down and popped her covers to prep for replacing the cam chain, etc. Luckly, I remembered to check out the orientation of
    Message 1 of 16 , Dec 7, 2013
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      Greeting,

      I just stripped the ol gal down and popped her covers to prep for replacing the cam chain, etc. Luckly, I remembered to check out the orientation of the sprocket arrows and the lower 1/4 alignment  point. The sprocket arrows align properly but the 1/4 point is what looks to be one space advanced from exact centered alignment with the crank sensor. Well sob, this might explain the light to lately moderate popping since my ownership. So, the big question is, should the crank point align exactly with the sensor? Or should it align on the advanced side of the sensor? Does the brain trigger once the point passes the sensor or at some point before? My gut says it should be dead center. Which likely means the Colorado stealer who wrenched her last missed the lower alignment by a tooth. Go figure..... Does the dead center orientation sound correct to you guys?

      Enjoy the ride,

      Samuel
      96 BBBB PB
      30kmi
      New Orleans

    • djacarr@sky.com
      According to the GBoH, it should align with the centre of the sensor. David ________________________________ From: Samuel Crider To:
      Message 2 of 16 , Dec 8, 2013
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        According to the GBoH, it should align with the centre of the sensor.

        David



        From: Samuel Crider <dieseldude1@...>
        To: triumphtrophy@yahoogroups.com
        Sent: Saturday, 7 December 2013, 23:37
        Subject: [TriumphTrophy] Correct cam chain installation

         
        Greeting,
        I just stripped the ol gal down and popped her covers to prep for replacing the cam chain, etc. Luckly, I remembered to check out the orientation of the sprocket arrows and the lower 1/4 alignment  point. The sprocket arrows align properly but the 1/4 point is what looks to be one space advanced from exact centered alignment with the crank sensor. Well sob, this might explain the light to lately moderate popping since my ownership. So, the big question is, should the crank point align exactly with the sensor? Or should it align on the advanced side of the sensor? Does the brain trigger once the point passes the sensor or at some point before? My gut says it should be dead center. Which likely means the Colorado stealer who wrenched her last missed the lower alignment by a tooth. Go figure..... Does the dead center orientation sound correct to you guys?
        Enjoy the ride,
        Samuel
        96 BBBB PB
        30kmi
        New Orleans


      • 703926d4809b9b1124ca684d7c612d3d
        Dead center; rebuilt mine after guide failure, new guides, chain & valves!; 5000miles after sweet as a nut.
        Message 3 of 16 , Dec 8, 2013
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          Dead center; rebuilt mine after guide failure, new guides, chain & valves!; 5000miles after sweet as a nut.

        • adeux60@ymail.com
          It should align with the timing marks not the lobes
          Message 4 of 16 , Dec 8, 2013
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            It should align with the timing marks not the lobes 

          • miles.french61
            Hi Sam I noticed exactly the same when I took a look : with the cam markers aligned, the bottom (crank) sprocket looks like it is one tooth past the centre of
            Message 5 of 16 , Dec 9, 2013
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              Hi Sam

              I noticed exactly the same when I took a look : with the cam markers aligned, the bottom (crank) sprocket looks like it is one tooth past the centre of the pick-up. The last person who lined it up was me, a couple of years ago, and I was being really careful. I never noticed any power loss. In fact it was red lining really easily, partly because the PO changed the sprockets. I'm replacing the engine, because some idiot thrashed it and now I have rod knock and flakes of bearing in the oil.

              I took photos of where the timing sprockets were. Very weird !

              Miles

              SSS (900) 94

            • miles.french61
              Sam, I’ve been looking into this (because I’m supposed to be working). If our engines were both one tooth out, with the crank rotated one tooth clockwise,
              Message 6 of 16 , Dec 9, 2013
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                Sam, I’ve been looking into this (because I’m supposed to be working). If our engines were both one tooth out, with the crank rotated one tooth clockwise, then we have retarded valve timing, which should result in hard starting, spitting and backfiring, but runs OK with the power band shifted up the rev range, with overheating and possible dieseling on shut-down.

                It is possible I had all these symptoms to a slight extent, except the dieseling. I thought my issues with starting and a slight misfire, (only when I feathered the throttle open just a crack), were due to a dirty pilot jet.

                Could it be that our cam chains were a bit stretched or the tensioner a bit slack, allowing the crank to jump one tooth ahead at some point, probably high-revs acceleration? The resultant localised overheating could have degraded the oil, allowing my big end to suffer. We need a fly on the cylinder wall.

                Miles

              • Samuel Crider
                Hi Miles, Sounds like a logical conclusion to me. That tensioner spring is of major importance. It s unbelievable that the spring alone is not sold on this
                Message 7 of 16 , Dec 9, 2013
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                  Hi Miles,

                  Sounds like a logical conclusion to me. That tensioner spring is of major importance. It's unbelievable that the spring alone is not sold on this side of the pond. Just replacing it made an alarming difference in engine noise levels. For the first time since I've owned her. She now sounds close to what I'd expect a new engine to at idle. Luckily, upon close inspection all of the internals look good. Can't see any difference in the new sprockets when compared to the used ones. Even the chain looks great. So, I think I'll just replace the chain and tensioner guide. And ebay the new sprockets. Went over all the valves and logged the readings. A few are pretty tight. One intake was under a .004. Which is the smallest feeler I currently own. I figure I'll go over them again just to be sure it's all straight. Also, unfortunately I borrowed a snap-on compression tester which promptly blew a hose. Bloody thing sounded like a pistol discharging right next to my ear. So, I just today gutted an old spark plug and silver soldered a diy compression tester. Now I can do a before and after just to be safe. Anyone know what would be considered the normal range for compression readings? She was up around 100psi when the hose cut loose. I just scanned over the good book of haynes and didn't notice any data.

                  Thanks to all the prompt replys. A2 I'm glad you pointed out the mark is separate from the lobe. Seems my brain wasn't keying in on this very  important fact.

                  This group is a wonderful, priceless resource. Many thanks to all for the help. I'm off to get back wrenching.

                  Samuel
                  96 BBBB PB
                  New Orleans

                  On Dec 9, 2013 5:33 AM, <miles.a.french@...> wrote:


                  Sam, I’ve been looking into this (because I’m supposed to be working). If our engines were both one tooth out, with the crank rotated one tooth clockwise, then we have retarded valve timing, which should result in hard starting, spitting and backfiring, but runs OK with the power band shifted up the rev range, with overheating and possible dieseling on shut-down.

                  It is possible I had all these symptoms to a slight extent, except the dieseling. I thought my issues with starting and a slight misfire, (only when I feathered the throttle open just a crack), were due to a dirty pilot jet.

                  Could it be that our cam chains were a bit stretched or the tensioner a bit slack, allowing the crank to jump one tooth ahead at some point, probably high-revs acceleration? The resultant localised overheating could have degraded the oil, allowing my big end to suffer. We need a fly on the cylinder wall.

                  Miles



                • adeux60@ymail.com
                  Cam tensioner spring is available from sprint manufacturing. Email me if you can t find it. Mine was 5mm short and would not stay to length when pulled out the
                  Message 8 of 16 , Dec 10, 2013
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                    Cam tensioner spring is available from sprint manufacturing. Email me if you can't find it. Mine was 5mm short and would not stay to length when pulled out the extra 5mm (just in case you are tempted) I bought the entire tensioner from triumph and then someone told me about Sprint. (they must have been listening)


                  • greg95ns
                    Hi Samuel, I ve done compression checks before, but not on my Triumphs. So I could be wrong here. Compression checks are done with a wide open throttle (WOT).
                    Message 9 of 16 , Dec 10, 2013
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                      Hi Samuel, I've done compression checks before, but not on my Triumphs. So I could be wrong here. Compression checks are done with a wide open throttle (WOT). We can turn the twist grip and open the throttle plates, but the vacuum slide will still be down and not letting the engine get a full breath of air on a compression check. I would think you will also need a way to open the vacuum slides while doing the test. I'm guessing the compression will be in the 125-140 lbs. psi area. What you are looking for is all the cylinders are close to showing the same psi.


                      You mentioned how important the cam chain adjustment spring is. I think of greater importance is the ratchet mechanism on the cam tensioner. Whenever the cam chain has a moment of slack the spring does its job and the ratchet holds it in place until the next time the chain gets slack.

                      The ratchet doesn't slacken in normal usage. It is the ratchet that keeps the cam chain tight not the spring.


                      Greg Andrews

                      '96BRG 

                      97,000 smiles

                    • adeux60@ymail.com
                      Miles have you picked up that you should be using the timing marks scratched on the plate and not the lobes sticking out of the side of the plate. I made the
                      Message 10 of 16 , Dec 10, 2013
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                        Miles 


                        have you picked up that you should be using the timing marks scratched on the plate and not the lobes sticking out of the side of the plate. 


                        I made the same mistake and everything looks half a tooth out  - it is exact when on the correct marks though...are they marked T1 from memory?


                      • Samuel Crider
                        Well my luck has just run out. Seems Triumph has sent me the wrong cam chain. It s a full 4 longer than the one I m replacing. Oh well, looks like another
                        Message 11 of 16 , Dec 10, 2013
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                          Well my luck has just run out. Seems Triumph has sent me the wrong cam chain. It's a full 4" longer than the one I'm replacing. Oh well, looks like another week or longer delay. This is enough to cause me to buy another bike. Then at least I could keep one ready to roll at all times...

                          Good job A2 on pointing out that the 1/4 tdc mark is next to the lobe. Mine looks like it was one tooth off of tdc.

                          Samuel
                          96 BBBB PB
                          New Orleans

                          On Dec 10, 2013 1:35 PM, <adeux60@...> wrote:


                          Miles 


                          have you picked up that you should be using the timing marks scratched on the plate and not the lobes sticking out of the side of the plate. 


                          I made the same mistake and everything looks half a tooth out  - it is exact when on the correct marks though...are they marked T1 from memory?




                        • miles.french61
                          Hang on in there Sam, it will be worth it in the end. I m sharing your pain. My replacement engine which has done 40,000 miles and looks lovely on the outside,
                          Message 12 of 16 , Dec 11, 2013
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                            Hang on in there Sam, it will be worth it in the end. I'm sharing your pain. My replacement engine which has done 40,000 miles and looks lovely on the outside, seems to have never been serviced. One of the valve clearances has closed up entirely - the inlet one nearest the cam chain – the same one as on my old engine when I did the shims a couple of years ago ! I can see a faint contact scrape round the back of the cam lobe.  I hope I haven’t got a burnt seat. Also the cam chain tensioner is only about 5mm off being fully extended (the spring is OK at 70mm long), and the tensioner blade doesn’t look very worn, so I suppose I need a new chain dammit. Does anyone know if I can check its length?

                            Dan, yes I was looking at the T1 mark, and I have photos showing that on BOTH engines - the old one and the replacement I’m putting in - the crank is I guess about 5 degrees advanced compared to the camshafts. I don’t suppose chain stretch could account for it. But if it does, there is a new reason for keeping an eye on our cam-chains. If they stretch a lot, then the valve timing is retarded, resulting in a high-rev performance boost, which is tempting but will result in local overheating (valve clearances closing up?) oil degradation, big-end trouble and other serious bad news. Wouldn’t it be nice to drop gears in to replace the cam chain!

                            Miles 94 SSS

                          • adeux60@ymail.com
                            It s always easy to point out ones own mistakes....be nice to get something right for a change.....lol Can the chain be shortened? Dan
                            Message 13 of 16 , Dec 11, 2013
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                              It's always easy to point out ones own mistakes....be nice to get something right for a change.....lol



                              Can the chain be shortened?

                              Dan



                            • Samuel Crider
                              Hey Miles, Oddly, pretty much the same story here. The two intakes nearest the chain were also the tightest on my gal. The one next to the chain was .003, the
                              Message 14 of 16 , Dec 11, 2013
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                                Hey Miles,

                                Oddly, pretty much the same story here. The two intakes nearest the chain were also the tightest on my gal. The one next to the chain was .003, the second .004. The chain guide looks almost identical to the replacement. Only a faint imprint where it applies tension to the chain. Pulled the alternator and it looks great, the brushes are in good shape. The cush drive rubbers are about half shot. Which is about what I expected to find. Closely examined the dreaded alternator drive bolt. It's not broken, but unfortunately I'm not sure if it's been replaced. The bolt face has circular raised ridges on top of the bolt head. Which I'm  assuming is an English hardness id. I  have a replacement, so I guess I'll replace it. Question is does the entire clutch pack have to be removed to access the nut side? Also, is it necessary to insert a rod during bolt removal? To retain alignment of whatever it's passing through. This morning I ordered the hopefully correct chain from the local stealer. Naturally it's not in stock and won't arrive till next Wednesday. While I'm waiting I guess I'll also pull the starter to check the brushes etc. Would like to install this 19t front sprocket I have on hand. But, I figure the chain will then be short.  So I guess I'll stall that until the chain needs replacement. Gonna be a long week... At least I won't be getting any tickets.

                                Samuel

                                On Dec 11, 2013 5:13 AM, <miles.a.french@...> wrote:


                                Hang on in there Sam, it will be worth it in the end. I'm sharing your pain. My replacement engine which has done 40,000 miles and looks lovely on the outside, seems to have never been serviced. One of the valve clearances has closed up entirely - the inlet one nearest the cam chain – the same one as on my old engine when I did the shims a couple of years ago ! I can see a faint contact scrape round the back of the cam lobe.  I hope I haven’t got a burnt seat. Also the cam chain tensioner is only about 5mm off being fully extended (the spring is OK at 70mm long), and the tensioner blade doesn’t look very worn, so I suppose I need a new chain dammit. Does anyone know if I can check its length?

                                Dan, yes I was looking at the T1 mark, and I have photos showing that on BOTH engines - the old one and the replacement I’m putting in - the crank is I guess about 5 degrees advanced compared to the camshafts. I don’t suppose chain stretch could account for it. But if it does, there is a new reason for keeping an eye on our cam-chains. If they stretch a lot, then the valve timing is retarded, resulting in a high-rev performance boost, which is tempting but will result in local overheating (valve clearances closing up?) oil degradation, big-end trouble and other serious bad news. Wouldn’t it be nice to drop gears in to replace the cam chain!

                                Miles 94 SSS



                              • miles.french61
                                Although there were still a few clicks left on my cam-chain adjuster, I bought a new cam chain and compared the length with the old one, using a huge Vernier
                                Message 15 of 16 , Jan 16, 2014
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                                  Although there were still a few clicks left on my cam-chain adjuster, I bought a new cam chain and compared the length with the old one, using a huge Vernier we have at work. And I did some Maths:

                                  With the old chain, the caliper jaws were 4mm wider

                                  So, the overall length of old chain (if cut and opened to one length) is stretched by 8mm

                                  Free length between nearest teeth on exhaust cam and drive sprocket is, say, a quarter of the total length so this has stretched by a quarter of the overall stretch, which makes 2mm

                                  Drive sprocket teeth are advanced by 2mm. The pcd is about 40mm (I guess), so its circumference is about 120mm. So a 2mm advance equates to 2/120 x 360 = 6 degrees !!

                                  Or, put the other way, the valves are retarded by 6 degrees.

                                  This explains my misaligned valve timing - see above, and possibly all the consequences, finally leading to a knackered engine. Our cam chains aren't jumping teeth, they are stretching. OK, they're not stretching, the pins are getting worn. I can see why Triumph gives them a relatively short life-span.

                                  Miles BBBS 94

                                • Samuel Crider
                                  Hey Miles, Great info! Here s the latest. I just got the old gal back in action. She s sounds better than ever. No more bucket of bolts symphony here. Just the
                                  Message 16 of 16 , Jan 16, 2014
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                                    Hey Miles,

                                    Great info! Here's the latest. I just got the old gal back in action. She's sounds better than ever. No more bucket of bolts symphony here. Just the slightest occasional pop at idle remains. Not sure if it's carb or valve seat related. As my compression tester failed and I never obtained any useable readings. Whatever the cause it seems to be slowly improving. Fwiw, beware of ordering the cam gears, timing chain kit from bike bandit. It arrived with a chain four inches to long. Plus slightly wider. Oddly, this kit is not currently offered by Triumph. Nevertheless, I had to return the kit and order from the local stealer. The bandit is researching the issue and may have already removed the kit listing. Went ahead and swapped the d&d's for the oem pipes. She's back to stealth mode. The d&d's sure are lighter which I'm sure equates to much less stuffing. Once spring spring's upon my hood. I'll crack them open and try to figure out the required stuffing volume to mimic the staintunes tone. Sure is nice to be back in the saddle again!

                                    Enjoy the ride,

                                    Samuel
                                    96 BBBB PB
                                    New Orleans

                                    On Jan 16, 2014 10:06 AM, <miles.a.french@...> wrote:


                                    Although there were still a few clicks left on my cam-chain adjuster, I bought a new cam chain and compared the length with the old one, using a huge Vernier we have at work. And I did some Maths:

                                    With the old chain, the caliper jaws were 4mm wider

                                    So, the overall length of old chain (if cut and opened to one length) is stretched by 8mm

                                    Free length between nearest teeth on exhaust cam and drive sprocket is, say, a quarter of the total length so this has stretched by a quarter of the overall stretch, which makes 2mm

                                    Drive sprocket teeth are advanced by 2mm. The pcd is about 40mm (I guess), so its circumference is about 120mm. So a 2mm advance equates to 2/120 x 360 = 6 degrees !!

                                    Or, put the other way, the valves are retarded by 6 degrees.

                                    This explains my misaligned valve timing - see above, and possibly all the consequences, finally leading to a knackered engine. Our cam chains aren't jumping teeth, they are stretching. OK, they're not stretching, the pins are getting worn. I can see why Triumph gives them a relatively short life-span.

                                    Miles BBBS 94



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