Primary Clutch heat

[yukon yamaha]

I have been fighting an up and down battle with my primary clutch heat. I know my belt mus tbe slipping to get heat like this from my clutches. I just cant seem to get it dialed in enough to get the temps down. After a good solid 20-30 min rip my primary is almost too hot to touch. I never had this issue with my 240 nytro or my custom mod nytro. I have put a black line up my primary to see how high my rides up the primary and I have just under half an inch of marker left.
Top rpm from a dead stop 8900-9000 under load it pulls down to 8600 and comes up to 8900 in deep snow on on a long pull.
I have installed vents on the machine and drilled extra holes for heat to escape under the dash and clutch cover.
Clutching in the machine:
secondary
39 degree helix @ 3-3

primary
Dalton 58g weights with .85 x2 in each
total 59.7g
14.5 rollers
spring yl/pk/yl
8JP belt
All help is welcome at this point
Thanks again everyone

 

[sk-rx1]

Obviously you are trying all the right things and I'm certainly no expert but have you tried different belts, 8DN or aftermarket. My 8JP was always leaving black marks on the primary.

 

[yukon yamaha]

I have not run an 8dn belt with the set up I have in it right now
This morning I took the one spacer washer out of the secondary three bolts to allow for some more belt deflection, the belt was on the tight side. Might be a start but don't think it will be the solution.

 

[stingray719]

http://www.ty4stroke.com/threads/clutching-on-the-cheap.129971/

 

[yukon yamaha]

You figure the shim is the ticket for the heat reduction? With a 4mm shim I should expect a higher total rpm by 300-400?

 

[stingray719]

You figure the shim is the ticket for the heat reduction? With a 4mm shim I should expect a higher total rpm by 300-400?

I believe the 8JP is slipping. I just posted the link in case you do not have time enough to mess with it and just want a tried and proven setup. Other option I would do if you need to keep this setup is 8DN belt and try the primary shims.

 

[yukon yamaha]

The three 1mm shims on the back of the secondary clutch bolts to open the sheaves up more?

 

[buddah]

The three 1mm shims on the back of the secondary clutch bolts to open the sheaves up more?

I would think (with my limited knowledge of clutching) that they actually cause the sheeves to close tighter.......i.e. you add washers as the belt wears and gets narrower in order to make belt ride higher in the secondary...........

 

[stingray719]

The three 1mm shims on the back of the secondary clutch bolts to open the sheaves up more?

Primary shims I meant, pull primary cover and put the washers/shim in and button up. http://www.ty4stroke.com/threads/primary-shims-made-easy-with-pics.130248/

 

[stingray719]

For 8DN belt specs look here please. - http://www.ty4stroke.com/threads/losing-rpm-and-not-holding-normal-top-speed.126678/

 

[yukon yamaha]

Sounds good I will try 4mm shim in the primary and see how hot the clutch gets after a ride.
Thanks

 

[NOS-PRO]

If you have a lot of belt dust, your probably slipping the belt.

My clutch temps are right around 104°

Here are 2 pics I took of my bellypan clutch area....this was 3 weekends of testing and riding after I changed my track out and cleaned everything. Roughly 600 miles

 

[yukon yamaha]

I do have a fair bit of dust on my clutches, With the shim it should increase my belt pressure and help the slipping?

 

[NOS-PRO]

I do have a fair bit of dust on my clutches, With the shim it should increase my belt pressure and help the slipping?

Hard to say....so many varibles with clutching. I would think the more shims, the less belt pressure, but in some cases Stingray's theory worked and put more pressure on the belt.

It's all trial and error with these sleds.... something will work good in one Viper and not good in another.

 

[yukon yamaha]

I figure if I go up to a pk/pk/pk primary spring I will get more total force while keeping my engagement the same, however my max rpm will be quite a bit higher, so dropping back to a lighter weight to adjust for the higher spring rate should account for the rpm increase and hopefully prevent as much belt slippage