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Gear Driven -- cams, primary

CYP77 - Police | Race Bikes | Choppers, Bobbers and Mods
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real_psyence
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Joined: Tue Aug 03, 2010 8:18 pm
Location: Baltimore, MD

Gear Driven -- cams, primary

Post by real_psyence » Tue Aug 10, 2010 7:54 pm

Just doing some thinking here while my engine sits in evapo-rust.

I see on the 500cc CB77 thread Jerry in Australia uses a gear-driven primary. Is this a one-off or does someone make a kit? I suppose custom would work well, as it's probably a custom dry clutch as well.

Also, replacing the cam-chain with gear driven cams. I know this is done on harleys and some automobiles. Is the sprocket a press-fit on the camshaft and crank?
Thinking of something like this: http://www.edelbrock.com/automotive_new ... ives.shtml

Ideas? Input? Thanks!

teazer
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Post by teazer » Tue Aug 10, 2010 10:40 pm

Anything is possible with enough ability, time, and other resources.

AFAIK, Jerry uses a different crank and a different transmission, then he cuts out some of the old crankcase material and welds in a ton of new material before he machines that to suit the primary drive and other changes.

Cam gear drive was done by Honda on CR72 &CR77 which are superficially similar to CB models. You would have to machine a new center crank pin, and find a suitable gear train. The cam sprocket is a hole other issue, but changing it to a gear would be the easiest part of that conversion.

You could look at a VFR gear drive. It won't fit, but it's a good place to start the exercise. Maybe there's a suitable NC30 part?

real_psyence
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Posts: 10
Joined: Tue Aug 03, 2010 8:18 pm
Location: Baltimore, MD

Post by real_psyence » Tue Aug 10, 2010 11:29 pm

Thanks for the pointers to the NC30. In fact, there's a gear assembly for one on UK eBay right now:
http://cgi.ebay.co.uk/HONDA-VFR-400-NC3 ... 0502269541

The interesting part would be finding a way to hold the idler in place while (hopefully) allowing for a little eccentricity from the crank. The chain roller mount looks like a start.

Thanks!

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