Re: [TriumphTrophy] Mikuni question
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- Sounds like your screws may not be closing. Are the -o- rings on them of the wrong thickness?
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From: "Greg" <gandrews@...>
Subject: [TriumphTrophy] Mikuni question
Date: Sun, Feb 17, 2013 6:49 pm
Hi All, The original Mikuni's from my '96 900 are living happily on my '98 Sprint Executive. For two years I've been using Keihin's on the Trophy. I miss the punch the Mikuni's give. So I bought a set of Mikuni's from eBay. I've been trying to adjust the air screws and have a question. Usually I set the screws at 1&3/4 turns out and leave it there.
Mikuni web site say that when the air screws are turned in (leaned out) the idle will drop and kill the engine. I can turn the air screws in all the way and nothing happens, turn them out 4 turns and nothing happens.
I've sprayed oil and air through the pilot circuit and it checked out fine. Float levels are good. What's going on? I'd appreciate any thoughts, thanks.
Carefully clean out all the micro passages with a small copper wire. It has to be able to conform to the odd angle turns inside the carb body. The only thing that I know that works is soft copper wire. Compressed air, super soaks, seafoam, whatever, won't dislodge the scale. I'd assume at least at first that the jets are hopefully unmolested.
96 BBBB PB
- Hi Guys, Thanks for the replies. The pilot jet is very small so I think it hasn't been drilled. The air screw looks good and the little bitty o-ring is in good shape.
Oh, by the way. TriumphWorld has good parts schematics, but one of them is wrong. Two of the pictures show no o-ring on the air screw, and the third one shows the o-ring in the wrong place. The o-ring goes down in the air screw hole first, then the washer, then the spring and then the air screw. My brother thinks of it in another way. He takes the air screw and first puts on the spring, the then washer, and then the o-ring. Same thing, the o-ring should be tight enough that the washer and spring won't slide off when putting in the air screw.
I'll take a pass on using a small copper wire. I don't want to make scratches in the aluminum passages. The local auto parts sells a can of carb soak that is big enough to dip a single carb. I think Bob had good luck when he did this. Air will blow thru the necessary passages, and Samuel has a good point about scale build up. I hope the soak will knock off the any scale.
While I was looking for a good diagram of the air passages I found that Mikuni has two different styles of pilot jets. I'll have to check that out. There is a nearby shop named Cafe Racer. They carry lots of carb jets and parts. Good folks. Lucky me, the local Triumph dealer, Engle Motors, are also good folks.
Thanks again for the replies,
Samuel Crider wrote:
Carefully clean out all the micro passages with a small copper wire. Compressed air, super soaks, seafoam, whatever, won't dislodge the scale. I'd assume at least at first that the jets are hopefully unmolested.