yz 125 won't start

[scha0786]

Got a 98 yz 125 and have rode it plenty this summer with now problems. Just this past weekend though was riding it like normal and it was running good, but when I shut it off for a second and tried to start it nothing. like it was flooded. got it going by popping the clutch and rode it back thinking nothing of it. tried to start it again and nothing. put new plug in and nothing. tried starting fluid and nothing. got plenty of spark and gas. then looked at the radiator and couldn't see any in there. so ok burned a ring thats fine. checked compression last night and it was 180 psi, so it most likely is not the piston and rings. By the way every time I took the plug out it looked like it had water on it. I am think blown base gasket am I close? or is there something else bigger i am missing here?

 

[rmc_olderthandirt]

If the head gasket was blown to the extent that water was leaking into the cylinder I would expect the compression test to indicate low.

I would certainly investigate where the water went. It is possible that it is the water pump seal allowing water to leak into the bottom end.

It would be a wise thing in general, however, to tear the cylinder off and do the top end. If you have ridden it "a bunch" and have no knowledge of when the top end was done last then I would say it is due.

Rod

 

[scha0786]

I have ridden it a bunch, plus when I bought it the owner stated it had a fresh rebuild on it. When I first changed the tranny oil it was milky white. since then I have changed it about 3 times and it hasn't been white at all, blaze red.
Is it hard to replace the water pump seal?

 

[scha0786]

ripped down the bike last night and the inner head gasket had two spots on it that were pretty black and pitted. I am hoping that it was leaking in that spot. also the pipe was full of coolant. tranny oil had no indications of coolant, but the crank has some coolant in it. Where could this leak be coming from, the head, water pump?

I am going to rebuild it with all new gaskets and put a pressure test on the radiator before I fill it with fluids, if it holds it was probably a head gasket, if not I'm pretty much stuck

any advice?

 

[AV8R]

Sounds like your on the right track. My guess would also be the head gasket.

 

[mxbrian199]

yea like people waterpump or head gasket