02 viper ER


Dealer, advertiser here on this site, post up a wanted ad in the classifieds here...

That said, you may be out of luck with 24/37 for an ER. The top gears are interchangeable with 00-02 SRX and likely a couple other models, and the only ones I've seen listed are 23 teeth and lower. The bottom gears are unique for reverse, and listed for 38, 39, and 40 teeth. Whatever you end up with, make sure you have the correct length chain, 68 or 70 link.

Why do you want a 1.54 gear ratio?
 
I have 8 tooth drivers, my calculations tell me 24/37 would get me back to stock. I could be wrong though, if so someone please correct me.
 
Call Tom Hartman, he is the guru of Yamaha sleds and will be able to tell you what's available and what you need to get where you want to be. Why did you change driver size? Did you put on a taller lug/longer track? You will probably want to look into gearing/clutching down a little bit if that's the case.
 
A friend of mine gave me a almost new 1.25 ripsaw already studded with 144 1.375 studs. Where is Tom Hartman located?
 
We are running 8 tooth drivers with stock gearing. The perfomance for two tracks is awsome. We are very satisfied with the performance. The milage stayed nearly the same. The Viper always gets the best milage out of all of our sleds.
 
Tom is very free with information. There is a whole page write up on clutch tuning and gearing. A stock sled is over geared by 10% to prevent over-revving at WOT when your running at full speed, but most sleds will never shift out far enough to use it all. Run it with the stock gearing and the 12% loss for a little while and see how it is, then call him if you want to make changes. There is lots of knowledge to be gained there. He is a little old school, you have to call him and most likely he will have to call you back. There is no cookie cutter solution for clutching, he will want to talk with you about your sled and how you ride it before he comes up with a parts kit for it.
 
what do you mean about "wound tight" did you tighten the secondary? With the 8 tooth drivers, the clutches easily shift into overdrive at WOT. We may have lost 5 mph at WOT. Still well over the tripple digits. Now, the Viper and 121 SXR are close to the same max speed, but the Viper will get there sooooooo much quicker.
 
alswagg said:
what do you mean about "wound tight" did you tighten the secondary? With the 8 tooth drivers, the clutches easily shift into overdrive at WOT. We may have lost 5 mph at WOT. Still well over the tripple digits. Now, the Viper and 121 SXR are close to the same max speed, but the Viper will get there sooooooo much quicker.
Click to expand...

Sorry, what I meant was way to many rpm's. I talked to Tom Hartman today and he has me convinced to work the clutches and leave the gearing. What did you do with your clutching?
 
On our Viper, the primary clutch is OEM set up. The seconday has the 41/53 helix. Same as comes from a RX1. The spring wrap is the same as in the OEM position. I can't remember exactly what the rpm's are, but nearly the same, only slightly higher than original.
 
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