Low compression???

[400ex18]

Can low compression cause my 250r to over heat? It has not loss any power but when i ride for like 30 min or less it has antifrezz commin out of the over flow!! So i was thinkin it might be low compession, last time i ran a compression test it was at 120!! so if anyone has any ideas please let me know!

[xlr810]

check your head gasket, the head itself, and top of cylinder surfaces.

An internal leak (between the cylinder and water jacket) can build up a lot of pressure in the cooling system.

A head gasket leak could also have something to do with your low compression reading. 120 is way low, so you likely need to rebuild anyway.

[400ex18]

ok thanks i will check that!! i was riding it a lil today and it seem to do fine and did not really get that hot!! So im gonna try to get my first race in with it the way it is before i rebuild it!! so hopully it will last!!

[Aceman]

Originally posted by 400ex18
ok thanks i will check that!! i was riding it a lil today and it seem to do fine and did not really get that hot!! So im gonna try to get my first race in with it the way it is before i rebuild it!! so hopully it will last!!

You most likely have a head gasket leak causing the low compression and overheating problems just like the guy above said. A little time and a new head gasket and it would probably be fixed easily before your next race. But if you think it's okay to run it, go right ahead:rolleyes: Must be nice having money to burn......

[86 Quad R]

i agree with what was previously mentioned. sounds as tho you may have a slight leak in the head gasket. after you run it a bit, things expand and is causing pressure to build in the cooling system. its not necceserily running hot on you.

i'd remove the head and inspect things. chances are you are getting coolant into the piston area aswell.

if the cylinder is in good shape, see what size piston is in it and hone it and install fresh rings and new gasket.