Hi All,
Bought a 250 Kazuma falcon that I have no history on and it wont rev up under load. Its an 06 auto.
Basically it starts and idles fine but when I accelerate it dies down.
It will gradually move off (faster if I get off and push) and then once it gets to jogging speed or more it accellerates fine.
I have pulled the carby apart(twice now) and cleaned it all out.(wasn't too bad). Plug is new.
Was thinking maybe the manifold had a hole in it so i drowned that in carby cleaner(thinking it may have had an airleak) and it made no difference
If I put it up on blocks ie take the load off, it revs up better.
Anyone got any clues.

 

I had the same issue with the Dinli 90cc I purchased for my son and found out it had the wrong spark plug in it. I did some research and purchased the correct spark plug and that was my fix.

 

Still sounds like you have carb issues had similar issues but mine was really gummed up after sitting 2 years.. I pulled the carb apart 4 times to clean. the last time i got some spray carb cleaner and sprayed every hole and passage.. Had some crud lodged in one i could not see. Dumped some carb cleaner in the tank as i noticed it was not feeding fuel fast enough... Took it out for a good hard run and everything cleared out.

You could have the start jet tuned way to high as well causing it to somewhat flood out and does not clear out until it builds up speed and power