Getting to the top of the Primary

[wavemaster]

2015 Viper XTX SE (625mi) - COTC (4 shims) - MBR Trail Can - 94 picks

How high should your belt climb up the primary clutch?

I can hit 90 now at will and it is about 9000RPM when it does. I have marked my primary clutch with a sharpie and it stops .425 from the top. Should it get to the top for max speed? Or how far should it get?

 

[Yamadog]

I have not measured mine since Allen Ulmer re-did it but before with Haucks clutch kit and 210 hp and overdrive on one sheave I was showing less than 1/4" to top of primary using an 8jp belt.

 

[wavemaster]

I am running the 8DN right now. It seems like getting to the top would produce more speed and I am close to 1/2" away.

 

[Yamadog]

It will I am not sure you have the HP to do it though. Hopefully someone like Nos-pro or cannondale can chime in on what they are seeing in thier clutching shift out.

 

[shagman]

It should get to the top. That sounds like coil bind in the secondary to me. Is your secondary stock other than helix for COTC? Who's helix do you have?

 

[wavemaster]

Ulmers RED secondary spring.
46/40 Dalton helix

 

[shagman]

Put your pink stock spring in and check results. Wrap at 6-1.

 

[shagman]

If your rpm's are high at 6-1, try 3-3.

 

[wavemaster]

Sounds good, I can change it now and test it tomorrow.

 

[shagman]

Great. Keep us posted.

 

[Studroes144]

Quick test, pull your primary spring out, put the primary cover back on and snug up a couple of the 10mm bolts, push the primary all the way closed to represent full shift and then put your belt in the primary, I'd bet your primary is fully shifted. With mine, (stock primary, no machining) it'll put the belt at around 1/4"-3/8" from the top of the primary. The primary just stops shifting.