Motorcycle Repair: 2000 Yamaha PW50 engine cutting out, intake manifold, low speed

Question
Hey Falcon,
The engine is cutting out at mid to high speed.  Low speed it runs great, but as soon as my 5 yr old speeds up or starts to go up a hill, it acts like its starving for fuel and quits running. Once he backs off the throttle, it will continue to run. Plug is new, fresh fuel, and all restrictors have been taken off. Trottle twist govenor, exhaust spacer, airbox stuffing has been removed.  What are your thoughts?
erik

Answer
Hi Erik.

Start by returning the bike to factory standard.  Then check the intake manifold and see if it is tight to the carb as well as to the head.  Also make sure that the manifold is free of cracks.

What you may have is a problem running the bike super lean.

Start with that and see what you find.
Good luck and ride safe.
FALCON