Question on decompressor cams on camshaft

1 reply to this topic
  • michaelschorpp

Posted April 29, 2005 - 09:27 AM


I've disassembled the decompressor assembly on the camshaft of my 92 XR600R. The shop manual doesn't make sense when it describes how the one way clutch outer rotates in one direction only. As far as I can see, the one way clutch outer is locked to the reverse decompressor cam and the whole thing is free to rotate either way. There doesn't appear to be any mechanism that would make it one-way. Any explanations?


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  • qadsan

Posted April 29, 2005 - 10:30 AM


It's been a good while since I've seen one, but there should be a one way roller bearing that only works when the engine kicks back during start up. Under normal operation the one way bearing has a tang on it that sits against a pin to prevent its outside from turning while its inside bearing is free-wheeling under normal operation and the right exhaust rocker arm rests in the down position. When the engine spins backwards from kicking back, the one way bearing catches and spins the outer camed body backwards, which raises the right exhaust rocker arm and relieves compression.

I think I recall that assembly spins in both directions while just playing with it in hand and there's some springs + weighted rollers that come into play through centrifical force which locks things down so that bearing only spins in one direction, but I'm not 100% certain on this. Like I said, it's been a good while since I've seen one of these, so perhaps somebody with more recent experience can better shed some light on this.

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