Triumphrat

ckassen

What are the signs of throttle bodies being out of sync(worst case scenario), and say they were out of sync, what kind of difference does syncronizing them make?

The reason I ask is because my bike doesnt idle real well, sounds like there is a slight misfire...It will also die if I really get on the throttle then pull in the clutch....

bradtx

ckassen, TB sync is most important for a decent idle. The procedure ensures that all three cylinders (for a triple) have the same vacuum, thus sharing the load equally. Out of sync enough can cause stalling when going back to the idle circuit from a higher RPM.

First ensure that the fuel isn't the problem by running gas from another source and general engine condition is good as sync'g the TBs is done after any other engine maintenance.

Brad

ckassen

I drive my bike every day and get gas from different places(2 for the most part). I just dont understand why it runs like it does, a fuel injected engine should run almost perfect. There also is not many other things that it could be....

fivehundo

That's the once piece of "required maintenance" that I frequently ignore.

I'm glad this came up, actually. Is it hard to do?

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rpwnyc

Hey all,

I have the same issue - if I rev the throttle and just let go of my right hand once the engine is warm, it'll stall out. Beyond irritating in traffic etc. I've had all fuel supply lines replaced, but my dealer said a mis-seated TB was probably the culprit.

What's involved in fixing this problem? Is this something you can do yourself, or a tricky engine tune that's best left to a dealer?

ckassen

Dont tell me that I have to go post this on the S3 section of the forum....

meanchuck

Have you checked your valves lately?

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ckassen

Checked them 5K miles ago, perfectly within spec. (that was at 18K miles)... Do throttle bodies have to be tuned for each particular motor?

staticman4414

I don't claim to have much if any knowledge about Triumphs, as i am a new owner myself. I am also fairly new to Fuel Injected bikes. However I have been around some other bikes with carbs. I know syncing the carbs can make a huge difference in a bike, especially at idle, and just in the smoothness of the engine. Just 2 weeks ago I took my wife's Suzuki RF600 apart thinking that the carbs might be out of sync. I don't have the proper guages, but i used some clear tubing and filled it about half way up with heavy weight gear oil. I taped the tubing to a yard stick to use as a gauge. I then attached the ends of the tubing to the vacume intake ports on the carbs. Basically connected one end to the vacume on carb 1 and the other end of the tubing to carb 2. I did this with the engine already warmed up. Then once the tubes were connected I started the engine again. Then i watched the oil. It would start being pulled toward 1 carb and away from the other. This meant one carb had more vacuume than the other. So i adjusted the throttle plate closed slightly on the carb that was pulling more. This brought down the idle a little and then I would adjust the idle back up across all carbs. Once i got carb 1 balanced to carb 2, I would then balance carb 1 to carb 3, and then carb 1 to carb 4. Once these were all done, I just checked across other carbs. For example Carb 2 to Carb 4, and Carb 3 to Carb 4 etc... And they all looked good. through the whole proccess i had to keep adjusting the idle to keep it in tune. When i was done with this proccess, the bike idled better than it ever has since I have owned it. (bought used) The throttle responce at slower speeds is much smoother and more responsive and the engine just sounds better.

Now how this translates to FI and throttle bodies, I am not totally sure. Maybe someone else will have more input. I would assume the theory is the same. Your throttle body is your throttle valve and if one is open more than another then I would assume that the air to fuel mixture on that piston will be different causing a rough running engine. I would imagine that adjusting them would be the same. The part I am not sure about is if the throttle bodies have have vacume port like the suzuki carbs did. I have also seen a cheap carb sync tool that would work on most anything I would guess. It basically covers the intake on the carb and messures the vaccume coming in. I have used that on VW engines that had 2 carbs fitted to them.

So please take this for what it is. It is a little bit of what I know. Not sure how much of it applies, but i would think the theory's might help a little at least.

Static

ckassen

Yes, the FI bikes(at least triumph) has these vacume lines(so it would be the same principle...What is this cheap carb sync. tool?