[korsonky]

Hey guys, I don't post here often but this site has been a godsend since I bought a used 04 F6 efi sno pro last year.

I am having problems in my clutching where after engaging around 4400rpm, the sled will accelerate up to around 5000-5300. Once it hits that range it feels like it is "down shifting" like when you go from 2nd to 3rd in a manual car; the rpms continue to climb but it bogs out just a little before it climbs. Sled seems to be smooth throughout the powerband and tops around 7900.

I marked the inner surface of both clutches and there is about a half inch line left on each one after WOT. I have 671/70g cat weights and what looks to be a very worn out black primary sprin, but the clutch is out of the box new. Also there are wear marks on the primary spring OD near the cover side possibly indicating a binding spring, is this most likely my problem?

Also I have a black secondary spring but an aftermarket BM40 helix. I know black magic is out of business but I cannot find the ramp angle info for that helix ANYWHERE, any ideas??

Sorry for the long post and thanks for any help you can give!

 

[acemaster101]

Could be a few things..

:Weak secondary spring
: Or engine movement

Sounds to me like the secondary is opening up too fast. Try more spring tension. If that doesnt do anything. It could be from engine movment. YOu may need a solid torque arm, engaging at 4400+ could be a bit much for a stock rubber torque arm, and it may be forcing the secondary open pre maturally. That happened to me. I now have a aluminum torque arm to stop engine movement.

If your helix is 40* thats pretty mild for a F7.... That shouldn t be a problem.

I have my sled engaging at 4850rpm now and have a much steeper angle then you

 

[hell cat]

cupple things to check make sure your weight are not turning on the pins the little set crew will back out some times 70 grams in a 600 sounds very heavy did the sled work good before or did this problem just happen.?

 

[korsonky]

Initially I thought the same thing, that BM40 was the ramp angle and that it seemed really shallow. However, I think that that is just the black magic part number because the have a bunch of different numbers like BM10 or 30 and the numbers do not generally correspond to the ramp angle. That is my frustrating because I can't find a chart or anything that give the angles for those helixs?

And the torque arm is a good idea too, although I'm actually running an F6 and not an F7 which is why I'm having such a hard time finding clutch info, everyone has 700's haha

 

[korsonky]

Hellcat, I've actually pulled the set screws a week ago to put new orings (or nylon washers ) on the weight pins, and I bottomed the set screw all the way in the groove on the pin and red locktight too. I don't think that's it. And I didn't really notice it running much different before but I do not remember it doing the downshift thing before. However this is the first time i've checked the shift engagement with a marker so who knows? The weights do seem heavy because stock calls for 65g??

And correction on the secondary spring, its actually black with red