rm 80 coolant keeps fouling the plug

[plezebeleveit]

I have an 89 suzuki rm80 and i just got it back out of the shop because of the expenses but it needed a new cylinder head, 2 pin,crank..?? not sure what that is,a new crank, and a new piston.. so I bought a freshly bored cylinder, brand new piston and rings and gaskets, the crank had a little bit of play in it but it seemed fine..so I put it all back together and it fired up in two kicks, I rode it arond for about ten minutes and it cut off so i took off the top end and the spark plug was fouled out by antifreeze and inside the cylinder head smelled like antifreeze so i wiped it all out and got a fresh spark plug and it fired right up again, but the same thing happened..I need to know why and how the coolant is fouling the plug? some one please help its frustrating

 

[Chris Long]

On my 2000 RM80 I had the same problem and it was the head gasket o-ring. My o-ring was bad and letting coolant into the cylinder. At one point it was spitting coolant out of the silencer. I got new o-rings and torque the head bolts down to spec and that solved it. The only way coolant could get into your cylinder head is at the top end gasket/o-ring.

 

[2-strokes-4-life]

did you check the crank for both side clearance and up and down movement of the rod?the rod bearing is a needle bearing so some movement side to side is normal but there is a max spec for it in the service manual for your bike.the rod should have zero up and down play.if it has any,the crank needs a rebuild and if the bike is allowed to run with a bad lower rod bearing your risking serious trouble.also if coolant is getting into the cylinder your running the risk of destroying your new piston