*HELP* Left Cylinder wont fire.

[dstroy12]

Everything was fine with my Chopper XS650, then I sold it. Then 2 wks later the left cylinder will not fire.

Things Ive done and checked:
Switched Spark Plug cables, left side still wont fire. Right is strong.
Removed carb, checked and cleaned left side.
Checked voltage at the posts going into coil. 12.36 to 13

Ive noticed if I really give it throttle, the left side starts to fire. but as soon as I let it goto idle, it stops. Air is coming out of exhaust, but is not hot at all.

also, at one point the left side was poping, and misfiring/backfiring. I thought it was a vacuum leak or something... I tried the Carb cleaner trick but then realizied there isnt any ignition in the cylinder to tell if there is a leak.

Im totally lost

Help!

Thanks a ton guys!

 

[Paulrxs650]

Hi

If this was sudden and you are getting the required fuel spark combo check the rubber diaphragm in the top of the left hand carb really carefully it will no doubt have a small hole tear in it. Happened to mine.

These are particularly sensitive to being removed and always benefit from a periodic spray with silcone spray to prolong longevity.

Paul

 

[xs650tony]

Also mine was firing on one only and figured out that the points to one cyclinder were shorting out on the point cover. Lined the inside with electrical tape and pow! Both were firing. Figured it out when I actually touched a pipe and it was cold after riding. Try running engine with points cover off