Posts
34
Joined
7/10/2017
Location
Miami, FL
US
Why does my rm85 keep blowing the inner head o ring it has blown it 2 times I bought a Chinese carb a pwk28 replica and after that it keeps blowing the inner o ring and the cylinder gets flooded with coolant I put a bigger inner o ring that I cut to fit and used some gasket maker to keep it in place and I also put a new keihin pwk28 I need to wait till the gasket maker dries but I doubt it’ll work can someone help me please
The Shop
Is there a kinked radiator hose or any blockage in the hoses? Blockage in the radiator? (You should be able to pour water right through these.)
When you have a completely cool engine, try running the engine and remove the radiator cap. You should see the water moving through. DO NOT OPEN THE CAP WHEN IT IS HOT!
How about other things to overheat the engine? Is your rider more than 120 pounds or so? riding in severely hot weather? Deep mud or sand? All of the above?
Is your jetting too lean? (White spark plug?)
X2 on making sure the head is flat. You may also want to remove the studs from your cylinder and check to see that the top is flat also, using the same method Lumpy outlined.
Make sure you are using the correct o-ring. You didn't mention your model year, but all models back to 1991 use 11147-03B00 (inner) and 11148-03B00 (outer). I always put a thin slime of grease on them to keep 'em pliable. Make sure you torque the head nuts in a star pattern and keep them at the same torque.
Try running richer jetting and/or race gas to keep the temps cooler. It may help. You might also check to see that the timing has not been advanced.
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