At a loss

[motorbikemikey]

I've looked for an answer, apologies if I didn't see it.

I have a Chinese 100cc but I've heard it is more like 80cc. It's actually my second one from the same company. Motor is broken in and was running pretty decent.

My most recent problem seems like a carburetor issue but I've tried 3 carbs all with the same result as well as 2 cdi's. I've tried all positions on the needle.. raising it up one was the best location. Now I have the "racing carb with the slide installed.

My magneto is good.

I have to peddle my butt off just to get it to fire halfway and then at full throttle it will run.. kind of peddling helps. A few days ago it would run great right off the bat for about a mile or two then it would backfire and die.
any ideas?

 

[ismellnownlatters]

Gas bad? Check compression ?

 

[motorbikemikey]

I've looked for an answer apologies if I didn't see it. I have a Chinese 100cc but I've heard more like 80cc. It's actually my second from the same company. Motor is broke in and was running pretty decent.
my most recent problem seems like a carburetor issue but I've tried 3 carbs all with the same result as well as 2 cdi's. I've tried all positions on the needle.. raising it up one was the best location. Now I have the "racing carb with the slide installed. My magnet is good.
I have to peddle my butt off just to get it to fire halfway and then at full throttle it will run.. kind of peddling helps. A few days ago it would run great right off the bat for about a mile or two then it would backfire and die.
any ideas?

Also have an upgraded NGK plug everything else is stock

 

[motorbikemikey]

Gas bad? Check compression ?

Gas is good I was thinking the compression but I checked the rings the rings are good I have ordered a new jug and piston and ring kit but it won't be here for 2 weeks

 

[weefek]

did you even bother to take the current jug off and inspect it before ordering new parts?

 

[motorbikemikey]

did you even bother to take the current jug off and inspect it before ordering new parts?

I did. It is scored with groves on one side. The jug I got on the replacement motor has a crack on one of the bottom fins that sits in the bottom end

 

[Nickt919]

Could be a timing issue with the backfires. Are you sure the magnets on correct … key in place … tight?

…And there’s different cdi’s and magnets. A mismatched CDI and magnet causes problems.

Great Magneto Mystery

 

[motorbikemikey]

Could be a timing issue with the backfires. Are you sure the magnets on correct … key in place … tight?

…And there’s different cdi’s and magnets. A mismatched CDI and magnet causes problems.

Great Magneto Mystery

The magnet gap is a bit off but it was working fine originally and I put back on the original CDI

 

[Nickt919]

That Grubee link is a good webpage on magnetos and CDI’s
Cannonball put me on it.

 

[motorbikemikey]

That Grubee link is a good webpage on magnetos and CDI’s
Cannonball put me on it.

Just noticed the link lol
Thanks