Clutch Selection - Cadet Junior Sportsman Yamaha

by **David Young** » Sun Mar 02, 2008 7:14 am

What's the best or most popular clutch for use in the Cadet Junior 1 Sportsman class? NTK has a good turnout in this class and I'd appreciate information as to what brand, 1 or 2 disk, and what rpm engagement speed seems to be best for the WA55B carbed Yamaha using the 4-hole can.

I purchased a used engine package that came with a 2 disk Tomar. Before I go through rebuilding it, should I switch to something else?

In advance, Thanks!
David

by **Dan Taylor** » Mon Mar 03, 2008 6:49 am

David,

We used the Horstman HDC5 single disc. They are very tough, parts are not that expencive, and there is usually a vendor at every track we go to that has parts.

Dan Taylor

by **Yaani-Mai Gaddy** » Mon Mar 03, 2008 1:00 pm

David,

Both the Tomar & Horstman are excellent clutches for the Yamaha motor. We prefer the Tomar as it is less expensive to rebuild and we prefer the design of the Tomar clutch.

by **Jerry Iseli** » Tue Mar 04, 2008 8:24 am

David;

One more vote for the Horstman HDC5A - single disk. Typically a 2 disk clutch is heavier than you'll need for Junior 1. You'll also want to run a larger rather than smaller drive sprocket, 11 or 12 tooth is preferred. The 10 tooth sprockets are a smaller diameter and don't hold up as well. 12 tooth will work at NTK but 11 tooth will be more universal.

7600 to 7800 rpm is usually a good engagement speed.

by **David Young** » Fri Mar 07, 2008 2:10 pm

To All,
Thanks for the replies and information.
Looking forward to coming to NTK sometime soon.
David