Runs On One Cyl

[banshee40001]

anyone have info on why only one cyl . operating on idle but rev it up and runs good has 3 hours on new top end new plugs carbs clean and delivering fuel , switched plug wires and still rh cyl runs off and on also pops loudly whenever????????????????????????????????????

[KRMit]

Only one cylinder is firing at idle, but they both fire at higher RPMs?

 

Sounds like your idle is out of sync. Take your airbox off and look in the carbs at idle. You may even want to stick something in there to gauge how much of a gap both slides have. Both slides should be the same height from the bottom and raise at the same time when you press the throttle. If you still have the TORS, there are two big knobs facing the seat. Those are what you use to adjust idle. Good luck, and let me know what you find out.

 

My carbs are in sync as close as I can get them and the cylinders still don't fire the same. I've given up on perfect synchronization and am saving for the Trinity CV kit.

[banshee40001]

if throttle is held 15% open it idles boggy , also what should my idle air circuit screws be set at i tried 1/2 to3/4 and ran ok but started this all of a sudden

[SDD]

Pull your pilot jet on the side that isn't firing. It's most likely plugged up with something like a piece of sand. You will need something like a needle to dislodge it.

[KRMit]

Pull your pilot jet on the side that isn't firing. It's most likely plugged up with something like a piece of sand. You will need something like a needle to dislodge it.

Then wouldn't it run lean?

 

Did you make sure to put the choke tube and crossover tube back on? Could it be something in the cylinders since they were just rebuilt? Have you checked compression? I don't know if this could cause it, but are you sure the float bowls are on the right carbs?

[SDD]

Pull your pilot jet on the side that isn't firing. It's most likely plugged up with something like a piece of sand. You will need something like a needle to dislodge it.

Then wouldn't it run lean?

 

Did you make sure to put the choke tube and crossover tube back on? Could it be something in the cylinders since they were just rebuilt? Have you checked compression? I don't know if this could cause it, but are you sure the float bowls are on the right carbs?

Yes it would run lean to the point where the cylinder would not fire with every revolution. This fuel mixture will build up inside the pipe until that cylinder fires and the flame front moves out the exhaust port and ignites the gas left over in the pipe. The "back fire" noise is the rapid expansion of this burning mixture. After time this condition will cause problems with reeds.

[wansomordis]

Wouldn't the first thing to check is to make sure the slides are in the correct carbs ???

[boonman]

Wouldn't the first thing to check is to make sure the slides are in the correct carbs ???

Why yes. You could check this on your way to pulling off the carbs to clean them.

[KRMit]

Yes it would run lean to the point where the cylinder would not fire with every revolution. This fuel mixture will build up inside the pipe until that cylinder fires and the flame front moves out the exhaust port and ignites the gas left over in the pipe. The "back fire" noise is the rapid expansion of this burning mixture. After time this condition will cause problems with reeds.

Yeah, sorry, got this post confused with another one. I was thinking this was the one where dude has oil coming out one of his pipes.

 

I really need to reread posts before replying.

[banshee40001]

thanks for all your help , checked compression and found left bank 130 and right 30 removed head and cyl on the right side and found something ripped two lines down the side of the piston causing the rings to stick hmmm no compression replaced piston and rings on that cyl now runs fine again , never found little bastard piece same thing happened to piston before rebuild

 

thanks again for everyones help-

[boonman]

c-clip perhaps? Is the cylinder gouged up at all?

[350duner]

That sucks. Hopefully whatever it was went out your exhaust and not down into the cases!