I have been battle a problem with my sons ETON 70 CC Two-Stroke for quite some time.

The problem is little to no power off the line when the unit use to pull wheels.

I was told that I needed a new spring in the clutch and maybe new rollers so I replaced both.
X-Power Clutch Roller Set 5.5G
Rear Clutch Compression Spring 1000RPM

I also added the following to give the ATV a little more power because they want more then original CDI could give.
DC Hi-Performance CDI Box with Digital Advance.

I cleaned the carborator, put in all of the new parts, and her comes my new problem. Power off the line is better, not great but better, but once you get in the power band, wow the ATV flies like never before.

I test ran it for about 10 minutes in the backyard determined it was good to go and that I would start putting all of the hardware, body panels, etc back on the bike. I put it all in take care to also clean the air intake and then ran it and the problems started.

It will not run wide open with the air filter in place. It runs full rev on/off almost like it has a restrictor CDI in it which it does not. (Yean, stop, Yean, stop, Yean, stop). Take the air box off if runs scary quick. But it back on serious problems running. I did not try running with the air filter box attached (without a filter), I will try that and report back.

Does anyone have any suggestions as to what the problem my problem may be?

Thanks in advance......

 

Don't know what the problem could be except with the high revs its choking out. You should pick up a cheap slip on filter and try that. It may be able to breath better

 

if it runs better with the air box off that means it is rich with the box on. try going down on the main jet size.

Mark