1981 RM 125 Radiator problem

Old School RM
Edited Date/Time 4/5/2012 2:18pm
Hello, I have a restored 1981 RM125 thats raceable and has been raced before. I have a problem with my radiator. I will fill the radiator with coolant, then crank the bike, but when I do, it gushes out the hose near the cap. So I replaced the cap and now I have a nee problem, it will start up, but only when I twist the throttle, the coolant gushes out again. Im thinkin it may be the gaskets so im gonna replace them, but if thats not the problem, theni have no clue what the problem could be. Any thoughts would be much appreciated. I would like to race it early next month. Help please!!!
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utzracing
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utzracing 4/5/2012 12:07pm
4/5/2012 12:07pm
Old School RM wrote:
Hello, I have a restored 1981 RM125 thats raceable and has been raced before. I have a problem with my radiator. I will fill the radiator...
Hello, I have a restored 1981 RM125 thats raceable and has been raced before. I have a problem with my radiator. I will fill the radiator with coolant, then crank the bike, but when I do, it gushes out the hose near the cap. So I replaced the cap and now I have a nee problem, it will start up, but only when I twist the throttle, the coolant gushes out again. Im thinkin it may be the gaskets so im gonna replace them, but if thats not the problem, theni have no clue what the problem could be. Any thoughts would be much appreciated. I would like to race it early next month. Help please!!!
You have a blown head gasket. or the radiator cap is bad. Check for erosion on the head surface also. Octane of gas could be too low. Had this problem in 1981.
Old School RM 4/5/2012 12:20pm
4/5/2012 12:20pm
Already replaced the cap so thats not the issue. Brand new cap from suzuki. Thats kinda what I was thinkin about the gasket, but I think we are gonna replace all of them now cause I have them. Hopefully this corrects the problem.
MXVet261
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MXVet261 4/5/2012 2:18pm
4/5/2012 2:18pm
Yes it sounds like the compression of the motor is going into the cooling system, popping the cap and spewing out the overflow.

Blown head gasket as was already stated.

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