Primary spring/engagement question?

[shredjim]

I just installed some clutching that included a 143/285 primary spring. I'm runing cat 73 gr weights, 48/36 P helix, shift assist, stock orange secondary spring, AMP deflection adjuster. My clutch engages at about 4100-4200 RPM which is supposedly correct for the kit, but I would rather lower it a bit. If I put the stock yellow/white spring back in which is a 122-285, it should lower my engagement - right?, with the same 285 finish. My question is - what are the drawbacks to a lower engagement and why would a performance clutch kit include a spring which only has a higher lower number - same finish - and therfore raises engagement? I top out at about 7800 RPM which numerous people say is what I should shoot for - 09 M8 SP, SW y-pipe & can, stock pipe. Others say 8000 RPM? I just bought Cutler 65-75 adjustable weights in preparation for my winter sleddig trip and want to take the primary apart one time only so I now need to determine the best spring. thanks

 

[White Rad]

lower engagement makes it a little easier to slowly walk the sled out of hole if your stuck and can keep the clutch engaged if your playing in the trees for smoother throttle. but to low and your clutches can run hot and some m8's bog on the low end if the clutch engages to low. mines an 07' w/ stock 44/40 helix but same spring in secondary and same weights in primary w/ the yellow white and it engages at 3800-3900 which i like for mountain riding. if you do pull the spring might want to put glide washers from high perf. engineering in there to keep primary spring from binding and hitting cup in the spider. you could try the yellow white and if its too low add these glide washers they act as shims to fine tune engagement as each washer increases rpm by 50rpms or so.

where is your trip? if its up north and you go through bellingham you should pick me up you know the trick w/ a 1/2in x 20 thread all-thread screwed into the crank with a washer and nut to compress the primary to easily change the spring right?