Thread: have a yamaha xt 250 with a knocking noise from engine?

i have a yamaha xt 250 with a nocking noise from the engine.its pretty loud like knocking on metal but other than that and occasionally dying at stops it runs good.any answers on it.and if its what ive been told it might be how long does it have before it stops running

Generally knocking noises from the engine only last a few minutes. then with a really loud knocking noise parts fly out the crankcase. Do not be in the way or you will be at least bruised.

try using pure gasoline, find a gas station where the gas doesn't have Ethanol in it (hey, it might work haha). If that doesn't work, look down the spark plug hole with a bright light, if the piston looks damaged on top, you could be in trouble. I wouldn't think a knocking noise would be easily anything else.

Did you change the spark plug(s) lately? if so, the spark plug may be too "Hot". Which can cause pre-ignition/detonation.

well you and i have the same prob. some guys told me that it can be the exhaust pipe can be loose it can be that its the engine rod is loose if that is the case your screwed but thats all they told me good luck bud

Sounds like a bearing in the crank, I'd fix it while it's cheap, if you run it until it stops it will probably cost more.

Sounds like a bearing in the crank, I'd fix it while it's cheap, if you run it until it stops it will probably cost more.