MOPED ARMY

Sounds like your experiencing a soft seize. The motor will turn over. It just won't start. I had the same problem on one of my Puchs. I knew the motor was running a little lean. But I just didn't have the jet I needed. My nephew was down here so I let him ride it anyway. Ran great for a couple miles and then just bogged to a stop. Seemed to turn over fine, but wouldn't start. Let it cool down for a while. And it was good to go. Took the motor apart because I needed the head for my Polini motor. You could see the scuff marks on the piston. Even though it still ran good when disassembled.

Try to go up 2 jet sizes and see what that gets you.

is your carb getting enough gas? doesnt sound like a soft seize, how long do you ride at full throttle before it does this?

I had the same problem and for me it was because i had drilled holes in the airbox i covered them up and it solved it , but then mystersly the problem has returned to my bike , id also check your spark plug i found mine was f*****

...if that's the problem, alex gets an assist!

LMAO!!

It does not sound like a soft sieze to me as it idles fine.

It sounds like you are not getting enough fuel flow to the float bowl to keep up with your high speed running.

Have you checked your fuel filters and the filter screen on the fuel tap up inside the fuel tank?

And adjusting the fuel mixture screw only effects idle. Does not do anything at fuel throttle.