My 70cc 2-stroke was running great. I started to notice a little bit being taken off the top end recently. It smoothed way out but got slower and slower. The other day I was cruising back from the store at like 18 mph (usualy in-town cruising speed for me) and I decided to open up a bit and check my top end. I got to about 25 and it started to back off. Then it jerked back a few times and then it sounded like it was getting mad at me so I slowed down. It ran alright at the lower speed. I though maybe I was running too lean, so I choked it a bit. Then my top end dropped to like 20. I took my carb apart, the jet is clean and there are no chuncks anywhere. The float had filled with a little fuel somehow. I got the fuel out of it and ran it down the street. Did not solve the problem. Then I took my needle down a notch to richen the fuel. Same problem and a really low top end. So I got brave and took the clip up to the leanest setting. Got up to 25 and was I surprised to hear... A BACKFIRE! Startled me more than a little. It was bogging in and out and lurching. I checked the exaust and it was clear all the way through. The only system I haven't check is the ignition system. Has anyone had any problems like this with the magneto or CDI? I don't want to just start buying stuff. That kind of defeats the purpose of these things you know. Any help would be appreciated.