Hey to all, last weekend me and my good friend were riding in the dunes. We were drag racing, i was on my z440 and he was on his yz 250 1997 dirtbike, I tried to find a dirtbike forum to ask this in but i couldnt find one that i liked and i figured an engine is an engine so you guys could probably help me.

My friend was driving along when all of sudden his engine lost all power and steam started blowing out of the radiator overflow tube and oil blew out of the exhaust

Then when he tried to kick start it it wouldnt do anything. It still has a tiny bit of back pressure but barely any, he can kick through it relatively easy.

So my question is, what is the list of possible problems, and....... how much can he expect to pay to get it fixed

Thanks for your help guys

 

Probably blew the topend. Needs new piston, rings, gaskets and a bore. It's been a while since I priced dirtbike 2 stroke stuff, but I would guess $200 for parts and $ 50 for the bore at a machine shop. And labor would be probably $ 175 or free if you do it your self. Hopefully thats all that is wrong. I have seen bits of the piston melt to the head, and I've seen a piston blow apart and get all down in the crankcase, so the only way to know what is messed up for sure is to take it apart.

 

My bet would be he blew his headgasket. This would allow coolant into the combustion chamber and the lost compression would enter the cooling sytem.