CRF's Only Forums

Can anyone suggest a reason please.
Had a 4hour cross country race today in about 80 deg F and the coolant level has really dropped (below the fins), using engine ice. This is the second time it has happened but not as bad as today.
The bike is a crf450R


Also had oil blow out of the rocker cover vent.

Any ideas?
Thanks

Have you checked the seal on your water pump. 450r is notorious for water pump seal leak . Especially pre 06 models. In 06, Honda drilled a whole in the impeller to help reduce unneccessary pressure on the seal.

The second issue could be coolant escaping into the trans through oil seal on water pump. Check trans fluid for traces of coolant and radiator/water pump for traces of oil. You can rebuild the entire water pump for around $100.00 (Gaskets, oil seal, pump seal, impellar, shaft).

Last but not least, check head gasket. If this one is it, your coolant could be blowing out the exhaust.