Radiator problems 89 cr 250

[Mike Nester]

Recently aquired 89 cr 250 from friend for cheap. Reason being it was generating alot of white smoke and the spark plug kept fouling out from coolant. After tearing down the head and cylinder I find no cracks so I replace the head gasket(which was the problem!) and put it back together. Start it up and waalaa no white smoke, but the overflow on the radiator is pumping out all of the coolant. In the past, I remember the guy complaining about it leaking fluid while we were out riding. I checked all hoses and connections, flushed out the radiator they all look good. I guess my question is what could be causing the problem? :(

 

[MikeT]

I wouldn't say that bike is "Vintage" because I used to own one. ;) Anyway, I think your head is warped..... Well, not your head, the bikes head. I think if you had the head and top of the cylinder matched by a machinist that would solve your problem. The reason you had white smoke is because coolant was getting in the combustion chamber. The reason you now have coolant leaking out is because the engines compression and the pressure from the exploded fuel/air mixture is pushing it out. Get it matched and the problem will be gone. If the head isn't warped, the sorce of the problem might then be old gasket material not cleaned properly from the head or top of cylinder. The head and top of cylinder junction is where the problem is.

 

[Oregon Trail]

Is it leaking from the radiator or head area? Do you have flow? How are the coolant passages? Could the radiator be clogged? Did you flush the system out? Just thinking of reasons that the head gasket blew.

 

[Ol'89r]

Mike.

You may also want to check the water pump, impeller, shaft, etc., and the area around the water pump in the side case. If the previous owner did not use distilled water in the system, there is a possibility that there are holes eaten through the water passages in the case.

I have seen this happen in several CR engines where distilled water was not used.