Nytro clutching.

[WFO or go home]

Few questions for the seasoned Yamaha guys.

I picked up a turbo Nytro and want to see how the clutching is set up before the first shakedown run.

Weights are 8BU with two steel slugs in them. I also got some aftermarket weights that have washers on either side held in with flathead allens.

I have only dealt with Yamaha weights that have three rivets in each. Are the 8Bu's a yamaha weight?

Secondary has shock wave and purple spring. Not sure if the spring is A/C or EPI.

19 tooth gear on top, can't remember bottom. Will check it again tonight.

I also have two different roller diameters, what is the benefit of the smaller/larger diameter?

TIA

 

[WFO or go home]

ttt

 

[Motleyone]

Few questions for the seasoned Yamaha guys.

I picked up a turbo Nytro and want to see how the clutching is set up before the first shakedown run.

Weights are 8BU with two steel slugs in them. I also got some aftermarket weights that have washers on either side held in with flathead allens.

I have only dealt with Yamaha weights that have three rivets in each. Are the 8Bu's a yamaha weight?

Secondary has shock wave and purple spring. Not sure if the spring is A/C or EPI.

19 tooth gear on top, can't remember bottom. Will check it again tonight.

I also have two different roller diameters, what is the benefit of the smaller/larger diameter?

TIA

Hey WFO,

I believe the 8BUs are Yammi weights, about 48 grams, used is higher HP apps (there are a couple 8Bus out there but the 8BU00 is the heavier). I believe the MCX kits are built using the Shockwave and stock Yammi arms and weights but it sounds like you have Supertips. Supertips are super adjustable and use 1 gram washers along with other weights like Tungsten Weights (7 grams I believe) and on your sled the 8BUs. I think the guy that had the sled took the 8BUs off his stock setup and put them on his new Supertips. I could be completely off there but that is what is sounds like. I believe the main reason Supertips are used with the Shockwave is for much more adjustability at lower elevation. The Purple is Cat and is about equal to winding the stock spring to 100 degrees to 120 degrees, the stock spring was Gr-Wh-Gr. Smaller roller diameters will lower the engagement point. The stock gears are 20/40 on the MTX but with that laggy MCX you will probably wanna stick with that 19T top gear to get the whole shot. lol, just kiddin man. That sled is so quick and powerful you will never open it up far enough to get the benifit of the 20T.

GL

Motleyone

 

[WFO or go home]

That sled is so quick and powerful you will never open it up far enough to get the benifit of the 20T.

I wouldn't put money on that if I were you...LOL.

Thanks for the info. I am thinking about putting a set of Polaris clutches on it and then I can have it dialed in 20 minutes.

If the smaller rollers bring down the engagement, I think I will put in the bigger ones, I prefer a little higher engagement. I may put the supertips back in it as well.

Hopefully we will get enough snow in early november for a shakedown run.

 

[MTN_VIPER]

Larger rollers will also raise your shift rpms slightly as well. May have to add a little more weight to bring the shift speed down. Smaller rollers increase primary weight force, while larger rollers decrease it. This due to the change in "working angle" of the weight to the spider.
Yammie clutches are pretty easy to tune, once you get familiar with the weights, etc.
8BU-00 where used in the old VMAX 800 4cylinder 2 strokes. They make a pretty good drag race weight, due to they're agressive shift profile.

 

[Motleyone]

I wouldn't put money on that if I were you...LOL.

Thanks for the info. I am thinking about putting a set of Polaris clutches on it and then I can have it dialed in 20 minutes.

If the smaller rollers bring down the engagement, I think I will put in the bigger ones, I prefer a little higher engagement. I may put the supertips back in it as well.

Hopefully we will get enough snow in early november for a shakedown run.

Early November snow would be unreal. This year is gonna be fun for sure.

 

[snowy1]

use the smaller rollers, you need all the belt pressure you can get with the turbo, abu-00 work very well the only benifit with supertips is adjustability. 19 tooth on top is lower and helps with clutching, you will have a huge performance benifit and belt life improvement with the smaller rollers, adjust ingagement with primary spring, some of the guys saying they are having belt problems is due to improper clutch set up, smaller rollers are a big improvement. polaris clutching will not out perform the yamaha, you have all the right parts just use them properly. run around 47 degrees on the helix. you will need to replace the epi purple about 300 to 500 miles, the stock as has been said will work at 100 degrees.

 

[WFO or go home]

Thanks Snowy1.

My polaris clutch reference was due to the fact that I have tuned those for years and it comes easy. I am planning to stick with the Yammie's for sure.

I need to find tuning instructions for the shockwave so I know all of the particulars on it's adjustability.