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Author Topic: 500 to 650 CAM swap - Tolerance between lobes and case?  (Read 993 times)

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Offline Puffin

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500 to 650 CAM swap - Tolerance between lobes and case?
« on: May 31, 2015, 04:29:13 PM »
Whilst rebuilding my CB500 engine I took the opportunity to swap the stock CAM for a 650 CAM.

Although all the lobes clear the engine case the tolerance by the #4 cylinder is very small however I can't make it physically touch by manually manipulating the cam and it spins freely.

At the time I left it but going back and looking at the pictures I'm not so sure?  That is one small gap..!

I've buttoned it all up now but if I need to go back and grind away some of the case then so be it.

I assume there is not a recommended set distance between the lobes and the case?  Is there likely to be any lateral movement of the CAM as the engine is running?

Any thoughts would be welcome.


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Offline Scott S

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Re: 500 to 650 CAM swap - Tolerance between lobes and case?
« Reply #1 on: May 31, 2015, 05:36:32 PM »
 I clearance that with a Dremel tool.
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Offline faux fiddy

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Re: 500 to 650 CAM swap - Tolerance between lobes and case?
« Reply #2 on: May 31, 2015, 11:38:07 PM »
Quote from: Scott S on May 31, 2015, 05:36:32 PM
I clearance that with a Dremel tool.

Not a bad idea. Grind some away, that's what it's there for.
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Offline SOHC4 Cafe Racer Fan

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Re: 500 to 650 CAM swap - Tolerance between lobes and case?
« Reply #3 on: June 01, 2015, 07:54:11 AM »
Quote from: Scott S on May 31, 2015, 05:36:32 PM
I clearance that with a Dremel tool.

It's a good idea to get some clearance Clarence.
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Offline Dunk

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Re: 500 to 650 CAM swap - Tolerance between lobes and case?
« Reply #4 on: June 01, 2015, 12:07:24 PM »
Definitely clearance it, with heat and speed things can grow and move a bit.
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Offline Puffin

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Re: 500 to 650 CAM swap - Tolerance between lobes and case?
« Reply #5 on: June 01, 2015, 09:31:12 PM »
Balls....!  You are all correct of course.

I'm kicking myself because I was meaning to clearance test the new CAM in the head before I installed.... but I totally forgot.

Guess I'll be undoing a few things tonight..  Gonna be fun doing it with the engine on the bike but I have one of those flexible dremel extensions somewhere.

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