Pitbike Racing Engine Problem

[marksl]

Hi,
My nephews both race pitbikes at a country track in South Australia, one of the bikes has an Intermittent problem where the bike dies in power and will either stop or the rider can use the choke and rev hard to keep it going. If it stalls the rider can re-start after a few kicks, then the bike runs fine for another 3 races, then the problem will re-occur. We have replaced the following so far coil, cdi unit, carby, checked wires valves adjusted correct, replaced plug.

Have run out of ideas, can anyone help. Engine is a Lifan 140cc

Thanks in advance

 

[pitmaster]

Are you running a fuel filter?

Maybe theres crap in the tank, and floating around the fuel system, that would explain why using the choke can keep it running,

(reduced fuel flow = lean condition = using choke = richens mixture back up again)

Just a thought, seeing youve already checked all the main areas already,

Goodluck

 

[orion125proseries06]

what about a new fiklter, i knw those crappy papery ones clog up and dont work properly, a guy at fort lytton had one of those, kept stalling on him, but this would not cover thechoke problem

 

[marksl]

found a link to a video on youtube in the forum about cleaning the carby there was some dirt in the carby so hopefully that was the problem, will find out during next weeks racing !