Primary clutch

[raptordan]

has any body machined out the pocket that the primary spring sits in.By opening up this pocket it reduces coil bind and helps the clutches to shift out further which should help in gaining top speed.I have done this on another brand of sled and the top end improvement was well worth it.I disassembled my primary today to install my clutch kit and noticed a lot of wear on the spring with only 400 miles.Any feed back would be great.Thanks

 

[Topgun]

I know I've thought about it. Also machine the inner id to fit tra springs so a guy could have a better selection of springs.

 

[grader]

the spring does not coil bind. the cap is app. 13mm from the spider when re-assembling the clutch. the movable sheave moves in app. 33mm. the heaviest yamaha spring fully compressed is 29mm. total compression of spring is about 46mm. most yamaha springs free length is app. 85mm. this means at full shift there is still room to compress the spring another 11mm. this is on stock clutches with no mods. the secondary clutch is a different story and can be modded to open farther.

 

[dirtmodified32]

grader:
what are the mods for the secondary and what would it gain?

 

[grader]

the mods for the secondary allow it to open wider to increase shift ratio, but are only helpful if primary is machined for overdrive.with secondary removed, assemble it with spring removed and open it fully with buttons touching the helix. the first thing to make contact is the bushing area inside the helix. this can be removed down to the bushing. most aftermarket helixes are already machined in that area. the easiest simple mod is placing 3 washers on the studs under the helix. i run a ring that fits over the 3 studs that is 4mm thick, origionally came from duane watt at hi-teck with an overdrive sheave for the primary. had the sheave re-machined to match stock angles, as his was multi angled and hard on belts.