Skipping, backfire, missing...just wont run right

[redhatman]

Hey guys ive got a freshly rebuilt blaster on my hands I bought used. wiseco big bore kit is in it, and a 38mm carb I believe. Oil block off, and tors out.

Either way, when I test drove it he put in a new plug because he was running a 16:1 for break in. I ran that plug for maybe 30 minutes, and it went out yesterday. The atv was skipping and backfiring a lot, and was just not really responding to the throttle. So I loaded the atv up and took it home.

I replaced the plug last night and fired it up this morning. Same thing. I have tried two different brand new plugs and it hasnt got any better. I emptied the gas and restarted with a mix of 32:1 It starts up fine if I have enough strength to kick it over enough but dies after a couple seconds, but will keep running if i give it constant throttle. it backfires a lot while misfiring. It ran fine yesterday!

92 octane, and valvoline 2 cycle.

What else could it be?

Thanks guys...
-Pat

[brianposs]

Check your flywheel. You may have sheared your flywheel key.

[redhatman]

Originally Posted by brianposs

Check your flywheel. You may have sheared your flywheel key.

How do I go about that? Where is it?

[Mert]

pop off your stator cover, on the left side of the engine, its somewhere in there, i never checkd it out though so i dont know specificaly where to look

[redhatman]

When you say left side of the engine, is that the side without the kickstart?

Where would I find the "flywheel key"

[FPMXer]

Yes the left side is opposite of the kicker. Remove the cover and the FW is the round object attached to the crankshaft. Grab it and see if it moves real easy or does it try to rotate the crankshaft. The plate screws might have rattled loose and the bike won't stay timed.

[johnmumie]

Try cleaning the carb....That's usually the cause of the back firing,missing,etc.First check the flywheel.I usually keep a few blaster carbs,cleaned,and jetted for each blaster,and soon as it starts acting up,I replace the carb,and it's good as new.