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Let's talk primary clutch rollers


I wonder if something has changed with Yamaha roller material that is used on newer sleds. I have just over 5K miles on stock 15.6mm rollers on MCX Nytro 270 with 86 grams weights and just went through my clutches. Without a question they are in perfect shape with minimal if any wear on the bushings. Looking at other posts Tarzan is successfully running a Nytro primary on his 375Hp Sidewinder and has not mentioned of any issues.
 
BADSLED said:
I wonder if something has changed with Yamaha roller material that is used on newer sleds. I have just over 5K miles on stock 15.6mm rollers on MCX Nytro 270 with 86 grams weights and just went through my clutches. Without a question they are in perfect shape with minimal if any wear on the bushings. Looking at other posts Tarzan is successfully running a Nytro primary on his 375Hp Sidewinder and has not mentioned of any issues.
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Yes, the Sidewinder clutch has changed. The SW clutch has a larger diameter for the weight hole and roller location. This was done by Yamaha to put more force to grab the belt....hence why it is on the Sidewinders and not the Vipers.

The rollers are getting pounded now with more force put to them. The previous Yamaha primary clutch (Viper, Apex, RX1, Nytro) on the Sidewinders running huge hpr does not smash the roller bushing like the Sidewinder clutch does. And having large, heavy and flat profile weights make it more common for the roller to go out than the more aggressive, curved weights that use less weight to achieve the same goal which is performance, belt grab and longevity. This is why we have changed back to the previous style primary and also a billet aftermarket primary on our own sleds.
 
Thunder Products said:
Yes, the Sidewinder clutch has changed. The SW clutch has a larger diameter for the weight hole and roller location. This was done by Yamaha to put more force to grab the belt....hence why it is on the Sidewinders and not the Vipers.

The rollers are getting pounded now with more force put to them. The previous Yamaha primary clutch (Viper, Apex, RX1, Nytro) on the Sidewinders running huge hpr does not smash the roller bushing like the Sidewinder clutch does. And having large, heavy and flat profile weights make it more common for the roller to go out than the more aggressive, curved weights that use less weight to achieve the same goal which is performance, belt grab and longevity. This is why we have changed back to the previous style primary and also a billet aftermarket primary on our own sleds.
Click to expand...
Terry.....What is the difference from Apex primary to Winder as far as Overdrive. How much do we lose? Also, do you feel the belt is grabbed hard enough with the Apex primary with 270+HP?

I will add, that my Winder primary with your TP rollers is doing well now with over 4000miles on them and 2700miles now on same belt. I feel like I don't want to sell her!!!

Dan
 
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Ran these duralon bushings in my 14.5 rollers with cat green set at 9-1 for 700 miles at 290hp in upper Michigan this weekend no problems . Stock bushings in sidewinder wouldn’t have made it 200 miles before . Would recommend it to anyone having bushing movement problems.
 
ROCKERDAN said:
Terry.....What is the difference from Apex primary to Winder as far as Overdrive. How much do we lose? Also, do you feel the belt is grabbed hard enough with the Apex primary with 270+HP?

I will add, that my Winder primary with your TP rollers is doing well now with over 4000miles on them and 2700miles now on same belt. I feel like I don't want to sell her!!!

Dan
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Dan, Great to hear our rollers are doing well :)

The Apex primary is losing a little overdrive compared to the SW primary. It's not a whole lot. How much? Depends on the power of the sled and snow conditions.

The question is....do you machine the Apex primary clutch or not? For those who want all the mph, I would say definitely machine for overdrive. The sleds we have machined for overdrive are seeing awesome mph, even with stock gearing.

Example, 290 hpr BTX SW running the Viper/Apex primary (Not Machined) with 24/50 gearing was 110mph no problem on trail. 141 XTX running 270 hpr with 21/41 gearing with Viper/Apex primary (which is machined) for overdrive was 128mph where 119mph would have probably been the limit if not machined.
 
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I took a couple pics to compare the fixed sheave diameter between the Apex and Sidewinder primarys...they are the same diameter. The second pictures shows the Apex fixed sheave overlaying the sidewinder fixed sheave.
As stated by the experts the diameter increase is only on the moveable sheave.
 
Thunder Products said:
Dan, Great to hear our rollers are doing well :)

The Apex primary is losing a little overdrive compared to the SW primary. It's not a whole lot. How much? Depends on the power of the sled and snow conditions.

The question is....do you machine the Apex primary clutch or not? For those who want all the mph, I would say definitely machine for overdrive. The sleds we have machined for overdrive are seeing awesome mph, even with stock gearing.

Example, 290 hpr BTX SW running the Viper/Apex primary (Not Machined) with 24/50 gearing was 110mph no problem on trail. 141 XTX running 270 hpr with 21/41 gearing with Viper/Apex primary (which is machined) for overdrive was 128mph where 119mph would have probably been the limit if not machined.
Click to expand...

How much material are you removing from the Apex sheaves for overdrive?
 
ROCKERDAN said:
For me, I simply used to idle my apex, and take a file to bottom of sheaves...did not have to remove much at the bottom at all to get belt to come to top.

Dan
Click to expand...

Years ago I removed .020" from both sheaves of a VMAX4 clutch by using varying grades of wet/dry emery paper on a flat surface, then I narrowed the lock collars on a belt sander...lol...bush league but it it seem to work well and had no failure issues.
:)
 
sideshowBob said:
View attachment 147691 View attachment 147692

I took a couple pics to compare the fixed sheave diameter between the Apex and Sidewinder primarys...they are the same diameter. The second pictures shows the Apex fixed sheave overlaying the sidewinder fixed sheave.
As stated by the experts the diameter increase is only on the moveable sheave.
Click to expand...

The difference in diameter is another reason why we have switched back to the previous style Yamaha primary.
 
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