Hi there,

I have been missing for a while. Sorry guys but i had a lot of things to think the last few months so i am back again. Lets talk about the problem I have!

3 months ago my bike started fouling the front spark plug. I thought carburators!!! So i pulled them out and i cleaned everything that had to do with the carburators, i set the float height and tested them. Everything ok. Placed them back, i changed the spark plugs and went for a ride. Same things again!!! I have checked my carbs 5 times. So I went for a crank rebuild.The mid bearing was at its last days!!! Rebuilt the crank and the engine and went for a ride. Same thing again. The front cylinder misfires at idle and a lot of fume comes out of the exhaust, this is unburned fuel. After 3 or 4k rpm the bike works good. Also when i try to hold the throttle between 2 to 4k rpm the right carb spills out fuel. Guys I've checked everything except the electrics and i have completely gone crazy. Please any advice would be welcomed.

Thanx in advance guys!!!

There's a common theme here I think!

Check the connectors to the coils. The can work loose and stop passing voltage properly, then the coil will not spark well at low revs. If the connectors are dirty, clean them well. Make sure they are a tight fit (squeeze gently with pliers)

Let us know if that helps.
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Dave

sorry to disappoint you but i have already checked this.I have also swapped the coils but same scenario.Don't know what else to check as I am completely disapointed.

Ok.

Can you explain what you mean by the right carb spills ot fuel?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

I think that I have used the wrong word!!I will try to find the correct word in a dictionary.Anyway, the carb shows me, the way it works, that the front cylinder has no compression or that i have used used big numbers in the idle and main jets but all the jets are normal!!I will try to play a little with the air screw and see what happens!!!!!!!

I ve played a little with the air screw.It is now set at 4 and half turns out.The bike runs better at low revs but at high revs it is lean.I can play with main jets but the bike runned really good with the stock setup before the problem and there is no temperature changes here in Greece.I will continue scratching my head until i find what causes the problem.

Try the next size smaller pilot jets.

Remember, carb tuning relates the jets to the throttle position, not the engine RPM. The pilot jets are for the lower throttle position, needle adjusts the mid throttle setting, and the mains are for wide-open throttle.

9 times out of 10, the plug fouling problems are due to the lower throttle position settings being too rich. Especially on the MC28. I am not that far above sea level, in a very dry area, and my bike runs too rich on the 38 pilot jets. I cant imagine the problems others are having at higher altitude and/or more humidity.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS