03 CRF450R Noise

Just bought a 03 CRF450R & at low rpm's it sounds like there is something smacking twards the back left of the bike. Could this be REALLY loud chain slap when the motor is at low rpm's? If i'm gassing it the noise goes away. I checked the chain tension & it seems pretty good. Also the chain is a DID O-Ring chain & the sprockets arent worn at all so were not looking at stretched out junk here.

Just wondering if anyone else has heard this?


when checking the chain tension did you have it on a stand with the wheel hanging free? The chain needs to be near the tight end of the manual spec (about 1-1/8" at mid point). My stock chain got loose fast and slapped a lot. Switched to a DID X-ring and almost never adjust the chain anymore.

had the same problem on my 04 450 and it was the chain rubbing on the little white plastic mud gaurd. tightened the chain and modified the gaurd and havent had a problem since.

its the chain. watch the stocker ... it will hit the frame. I made a little nylon piece to protect mine. I bought new steel sprockets and a cheap x ring chain from parts unlimited about a year and a half ago and i only adjusted the chain 2 times since.

Adjusted the chain... No more slapping :naughty:

But now the waterpump is leaking from the weep hole. When I first start it it dumps a 3" puddle, seems to get better as it warms up but does not go away.

I was told the seal is ceramic & if the bike sits for long periods of time this will happen & it just needs to be ridden to correct the problem.. :naughty:

Ive also read the shaft bearing goes bad & the little bit of play wont let the seal do its job. What do you guys think??? How hard is it to change the bearing & the seals? Have any of you done it or know what the parts cost?


I wouldn't just ride it and hope it goes away. If the bearing lets go it will be very expensive. Replacing everything is not difficult but does require a special Honda tool. If the counterbalance shaft is not bad it won't be very expensive - around $40. If the shaft is worn it will have to be replaced and that costs about $110. Service Honda is the cheapest I have found. PM me if you need detailed instructions.



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