1999 yamaha 100 four won't idle?

[zoomzoom1970]

Cleaned all 4 carbs still running the same. Top 2 spark plugs look really gas fouled, could it be the coil for the top 2 cylinders?

 

[zoomzoom1970]

Re: 1999 yamaha 100 four won't idle?

Hello,is anybody out there!!!

 

[timster]

Re: 1999 yamaha 100 four won't idle?

have you checked for spark on those two cylinders?

 

[rodbolt]

Re: 1999 yamaha 100 four won't idle?

cylinders 1 and 4 fire from the top coil and 2 and 3 from the bottom.
rules out a coil.
did you drill out and remove the brass plugs that cover the air fuel screws and clean that passage?
did you reset all shutters with a 4 channel manometer?

 

[bud63]

Re: 1999 yamaha 100 four won't idle?

Did you check your timing?

 

[rodbolt]

Re: 1999 yamaha 100 four won't idle?

why check timing, its not adjustable.
its either where it supposed to be or broke.
no moving parts,other than a flywheel and the TPS really involved in timing once the engine is warmed up.
I would test leakdown then go fix the carb issue.