01 XCSP Backfire/Miss issues

[snowkoch]

Went thru carburetors and needle/seat twice, no blockages,etc. Will run top end fine, when let off gas it backfires, seems to skip a beat and occasionally won't idle correct. Anybody have any experience with this? I've had 3 people look it over and no clues yet.

 

[lewisb13]

Backfiring is caused when unburnt fuel hits the hot exhaust manifold and explodes there instead of inside the cylinder. This tells me that you're not igniting ALL the fuel INSIDE the cylinder head. Check plugs, timing, coils, etc...

 

[indy_500]

might wanna test the stator.

 

[xcsp]

May be a longshot, but could it be the throttle override and throttle cable adjustment?

 

[North of 2]

Check the manifold gasket. If it is burnt out there isn't enough back pressure.

North of 2

 

[artic570]

X2 The throttle overide cable adjustment.
A friend of mine is having similar problem and he has no play in throttle lever.
I had a similar idle problem on another friends 550 classic. I adjusted throttle free play and all was good.

 

[snowkoch]

Thanks for the great suggestions. Exhaust gasket seems to be fine, will work on the throttle cable adjustment next. Tried to pull the fly wheel off (someone thought the key might be broken inside causing it to skip a cycle) but can't peel off yet. Might have plenty of time until next ride....

 

[harvest1121]

Look in the tank my friend had the problem of the gas line falling off. It will run great then miss.