Dear MXA,
I live in mortal fear of my CRF450 blowing up. I came from a two-stroke background and never gave a second thought to the health of my engine, but now I have an hour meter and listen to every creak and groan. I have 40 hours on my CRF450. When should I rebuild it?
Assuming that the compression is good, there are no strange noises and the bikes starts easily, we don’t think that 40 hours is long enough to worry about. As a rule of thumb you should check the valve clearance at closer and closer intervals as the bikes get older. Any change in valve clearance is a sign of danger. In the next 40 hours you will need to change the cam chain and piston, but 80 hours is a good ballpark for a well cared for four-stroke. All that said, we've blown up engines in 22 minutes.
|
|