3C engine build

martymoose

martymoose

Hero member
Location
Sydney, Australia
Finally have some time to spend on the 3C. First problem I've come across, the nylon wheel on the cam chain tensioner has seized and worn a flat spot. I have a new one, but it involves making up a new rivet to hold it on the pivot. What is the preferred pin material, cut down a bolt? Heat the pin to mushroom the head may effect the nylon wheel, did the factory just bash the snot out of the ends of the pin?
 

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Marty,

It really isn't so important to have that wheel rotate freely, it simply pushes the tensioner blade. The flat has been caused by a too loose chain flapping and hammering on the blade for too long. In service, the wheel doesn't rotate!

Spin the wheel so an un-damaged part rests on the blade and you're good to go. All the radiused part of the wheel is intended to do is provide a linear movement when tensioning the chain. The 500 has a pretty similar set-up, but the wheel is replaced by a swivelling shoe that pushes the tensioner blade.

Don't over-think it!

Just my $0.02, from an engineers POV.

piet
 
martymoose said:
Thanks Piet. I was thinking 750, wheel in contact with the chain. Doh! It's been a while since I pulled it apart.
Click to expand...
That little wheel wouldn't last 10 minutes if it were driven by the timing chain!

Any old mild steel would be ok for a rivet should you decide to replace it.

piet
 
on my race bikes, I changed the tensioner wheel set up on the triples to a foot set up as used on the 500's as my first attempt to try and stop the tensioner blades from breaking
I thought the point contact of the wheel was an issue, turned out I had more issues then that
Hence finally going to Slipper clutches which has solved fairly well every issue I have with my race engines
 
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