primary clutch rollers

yamiman

yamiman

New member
Joined
Dec 22, 2003
Messages
130
Age
45
Location
grand forks north dakota
how do i measure the rollers on my viper? i bought the sled used and had problems with my sled pulling rpm and ive done everything possible. on hardpack it will pull 8500 but in deeper but lighter powder it will only pull 7800-8100 rmp. i bought this sled used with a 141" kit on it since then i made it into a 136 with a 1.25" track. all the clutching is stock, now i have my doubts with the rollers. this is all at sea level
 
The rollers are marked or unmarked. Yours should be 14.5 mm which is the smallest roller Yamaha makes. It has a groove on one side & slightly machined edge on the other side. The problem you are experiencing is lack of backshift cus your sled is clutched on the edge. Lightening up the primary by a gram or 2 in the inner hole should fix ya right up.You could also go to a stiffer primary spring but lightening up the weights would be the proper way to get some backshift.You also might have a wicked steep helix also which can do the same thing.
 
A helix about a 48/40 ish would help a lot if you are using a 45.
 
You need a helix with a lower finish. If you have a straight 47 now try a 51/43. RX-1 helix works great & used ones are cheap.
 
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