ok so I have a 1989? Yamaha moto 4, starts up and idles fine, but as soon as you try to rev it, it wil rev up a until about 1/2 throttle, any more it will bog and die. it has no power at all. the bike has great compression, (around 180 psi). it only started doing this after I slid into a snowbank. bad coil? please let me know!

 

sounds like you may have loosened up some debris. pull the carb apart, pull the jets and clean them. clean the needle valve/seat while you're in there. reassemble and ride. if you don't have a fuel filter on it, cut the hose from the tank in half and put an inline filter in there.

 

i have done that about 3 times now.. and it does the same thing. doesnt have a vaccum leak from what i can see. would this be a timing issue?

 

try running it with the headlights on for a little while ( it sounds stupid but trust me)

 

make sure to drive it with the lights on

 

What will it do? I dont understand, maybe more stress on the engine or something?

 

just try it and see what happens if it works i'll tell you what you need, just drive it with the headlights on!

 

Alrighty, thanks! Ill let ya know

 

ok, cool

 

so did it help?