03 660 Sudden Engine Noise
#1
05-24-2017, 07:23 AM
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03 660 Sudden Engine Noise
New to the forum!
I bought a 2003 660 Raptor late last year. It is in VERY VERY nice condition, very low hours. The only issue it had was some minor blue smoke on start up, which I diagnosed as valve seals. I tore the engine down (I am very meticulous) and replaced the valve seals and 3 valves (the valves seemed a little worn, lapped new ones in). While I was in their I measured the stock piston and cylinder.. both were well within spec. So for good measures I just installed some new rings. I put everything back together and also installed a Stage I hotcam. The smoke disappeared (like I expected) and the motor purred like a kitten (and ran like a raped ape).
Other mods include full exhaust (new) and dynojet kit with airbox mod.
Fast forward about 30-45 mins of riding (gentle riding) and all of a sudden I get motor noise. It went from dead quiet to a knocking sound in 2 seconds. The sound goes up/down with revs. It's hard to pinpoint the source.. sometimes it sounds like top end (valves) and other times it sounds like mid/bottom end. It's not too deep, not to high pitched either. The cam chain and tensioner were well within spec and it great shape (less than 1/2 out).
Bike runs great but is now noisy. Again, it went from quiet.. to instant and constant noise. I'm a little puzzled on what could of happened so quickly and under such gentle riding that now makes it knock. One a scale of 1-10, 10 being about to explode and 1 being slight valve noise.. I'd say it's about a 5. Certainly doesn't sound great.
Thoughts?
Thanks
I bought a 2003 660 Raptor late last year. It is in VERY VERY nice condition, very low hours. The only issue it had was some minor blue smoke on start up, which I diagnosed as valve seals. I tore the engine down (I am very meticulous) and replaced the valve seals and 3 valves (the valves seemed a little worn, lapped new ones in). While I was in their I measured the stock piston and cylinder.. both were well within spec. So for good measures I just installed some new rings. I put everything back together and also installed a Stage I hotcam. The smoke disappeared (like I expected) and the motor purred like a kitten (and ran like a raped ape).
Other mods include full exhaust (new) and dynojet kit with airbox mod.
Fast forward about 30-45 mins of riding (gentle riding) and all of a sudden I get motor noise. It went from dead quiet to a knocking sound in 2 seconds. The sound goes up/down with revs. It's hard to pinpoint the source.. sometimes it sounds like top end (valves) and other times it sounds like mid/bottom end. It's not too deep, not to high pitched either. The cam chain and tensioner were well within spec and it great shape (less than 1/2 out).
Bike runs great but is now noisy. Again, it went from quiet.. to instant and constant noise. I'm a little puzzled on what could of happened so quickly and under such gentle riding that now makes it knock. One a scale of 1-10, 10 being about to explode and 1 being slight valve noise.. I'd say it's about a 5. Certainly doesn't sound great.
Thoughts?
Thanks
#2
05-24-2017, 06:49 PM
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Join Date: Jan 2016
Location: Penobscot, Maine
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It's pretty easy to check the valve gear. If that's not it, then it could be more serious, like oil pump failure, or a piece of crap plugged up an oil journal, etc. Sounds like you are able to tear into it and get to the bottom of it. Don't know how easy to check oil pressure in that model. I put an oil pressure gauge in my old Arctic Cat 500 , made me nervous enough to replace oil pump. It had about 8,000 miles. I sold it with 9,000 miles, the new oil pump saved it. It would drop almost to 0 at hot idle before, new pump more like 20-25 psi at idle. Here's a picture of the gauge after new pump.