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<  Performance issues  ~  DOHC crank in SOHC engine?!

lordmoonpie
Posted: Fri Aug 04, 2006 6:04 pm Reply with quote
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I've got a DOHC crank going into an SOHC engine for a CB750. I've sorted the primary drive, chain and tensioner but don't know what to do about the camchain sprocket or camchain tensioner. Presumably I have to use a DOHC camchain tensioner on the hy-vo camchain, but how do I fix it up in the SOHC engine?
Also, what donor bike can I get the correctly geared camshaft sprocket from?

Any ideas gratefully received - in fact the first detailed solution for both I'm prepared to send the poster a pair of screen sticker for their bike of their name or nickname!
Cheers
Simon Shocked
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Satanic Mechanic
Posted: Sun Aug 06, 2006 8:24 pm Reply with quote
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The DOHC cam sprocket will at least have the correct number of teeth, but I have no idea how it will fit the SOHC cam.
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Satanic Mechanic
Posted: Sun Aug 13, 2006 5:05 pm Reply with quote
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The CB 400 N cam sprocket is supposed to fit the DOHC cam chain and the SOHC cam.
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lordmoonpie
Posted: Mon Jan 07, 2008 9:50 pm Reply with quote
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Satanic Mechanic wrote:
The CB 400 N cam sprocket is supposed to fit the DOHC cam chain and the SOHC cam.


Well it's the right profile at the teeth end of things but doesn't have the right cutouts for the megacycle or the right thickness to clear the cam tunnel....but what it did do was allow me to take that plus a good SOHC cam sprocket and get one made that was the hybrid son of the two!

So - just the cambox cover to fit now which doesn't fit on a hy-vo camchain in a SOHC head...otherwise I'm there, DOHC crank in an SOHC engine....on the bench Very Happy
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Satanic Mechanic
Posted: Tue Jan 08, 2008 9:06 am Reply with quote
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Good to hear you are making good progress!

What are you using for a primary chain tensioner? I am somewhat stuck there with my turbo / auto crank project, and suggestions?

Cheers,
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lordmoonpie
Posted: Tue Jan 08, 2008 7:58 pm Reply with quote
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Ah, tensioner is not so easy I'm afraid. Front tensioner is a CB200N which is obsolete so you'll have to search for that. For the back tensioner I followed what I've done previously in my CB350 race bike and made a slipper tensioner. Basically you get two pieces of 2mm stainless steel and a block of 16mm thick teflon. Shape them so you sandwich the teflon in the steel and shape to the same bow type profile as the original tensioner. Cut a hole through the base to take the pin that goes into the crankcase mouth and you have a slipper tensioner.
The only issue I can see is that with the hy-vo chain it doesn't fit as well lengthways between crank and cam so you either have it way too tight or too slack so the tensioner is doing a lot of work. Worth a try though Smile
When I get it all finished and write the build up I'll post a link to it all so you can see for yourself.
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