Sounds like you need a carb clean and/or carb kit. New jet and needle perhaps.

 

Thank you

 

Does it miss and backfire under load or when you let off?

 

When you let off of it

 

It could be a dirty carb as stated above or it could be a lose exhaust. Mine was loose and backfired when you let off. The pipes had a lot of soot around the joints. How often does it backfire?

 

What speed does the missing start at does it have the stock CDI and is hitting the rev limiter

 

I would guess at top speed this is the first time I have ever been on one. I would say it has a stock CDI so is that normal when you hit the limiter. Does the backfire sound like a dirty carb?

 

Ya when you hit the rev limiter is will back fire and miss. It should be around 41 if it is stock

 

It backfires every time you let off of it at high rpm

 

Odds are the carb has been mal-adjusted in the past...could be an exhaust leak also but 99% of the time it is lean at idle...that can be dirt but not likely...if your idle circuit/pilot jet were plugged it would not want to take off well and would back fire and die when you try to take off...

If you don't have an exhaust leak...take the carb out and look to see if it has ever been opened...open it...clean it...inspect it...find the a/f screw...if it is capped that is actually good thing...if no one has ever opened that is even better...in any event...your idle a/f screw should be at least 2.5 turns out from fully seated with the stock pilot jet (40)...

 

Do the valve adj it worked on mine . My carb was in good shape just vavles were out of adjustment

 

Looks like the has been apart

 

I had several things going at once earlier so I didn't mean to make it sound like checking your valve clearances was a bad idea...gets a little confusing to me sometimes helping four people at once with similar problems...lol..

But if you carb has been opened you should remove it...clean it...inspect it...document the jets that are in it...needle type...needle position...and the idle a/f screw setting...

 

Thanks I will do that