My Clutch Setup So Far

[wavemaster]

With info from the clutching on the cheap thread here,
http://www.ty4stroke.com/threads/clutching-on-the-cheap.129971

2014 SR Viper XTX SE

We have such a short season here and I had the sled early so I will be starting the season with these mods done.

I did my normal hot supper beat in for 2 miles on the stock setup prior to changing the oils and beginning the mods.

This is all bench testing with only the track for resistance, so the actual top end and rev-limiter will be different on the snow.

Shop temp was 65deg and the sled temp at start of each 10 pull test was 150deg

I did 10 full throttle cycles and was going for a full three second count on each of them.

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Prior to any mods full three count on each full throttle hit

On the 10 first runs I saw 108-109 on most and 112 on one that hit the rev limiter and a couple low 103 and 104, with an average of 107.

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Mods so far,

New 8DN Belt

Primary Clutch,
Green/White/Green spring
5mm shim on spring.
8fp weights with 3gr rivets in the end holes

Secondary,
Removed the three screws from the back
Dalton 46/40 Helix (from Ulmer)
Changed to Red spring (From Ulmer) to eliminate the spring bind issue. Set on 6/3 helix/sheave. You will need two guys to get the twist on this, it is a stout spring.
OSP belt adjuster to set belt deflection

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Results,

First thing to note is I hit the rev limiter at the top on EVERY test in about 2 1/2 seconds. I am not going to worry about it right now because in the snow it will be under a real load not just track load.

10 runs up to the limiter 2 1/2 to 3 seconds each

Very consistent 117-118 on every pull. Average 117.5

Not a real test being on the bench but real in the sense that it consistently went faster in less time. Not sure exactly how it will translate in the snow but it will be better for sure.

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The only other mod prior to the season will be the MBRP trail can if it ships in time. I ordered it two weeks ago.

Very happy with the results so far and very thankful for the information provided from members here - you guys all rock!

 

[stingray719]

Did you use 8FP weights or 8JP (8jp are stock)?

 

[wavemaster]

Nice catch - The 8FP I will edit the above - thanks.

 

[stingray719]

With the flat profile 8FP weights you may have the secondary wound too tight. You may want to back that down to 6/1 or even 3/3, back it down until you don't dig a trench taking off. Winding the secondary tight helps takeoff but hurts top speed.

 

[wavemaster]

Great feedback.

Clutching is voodoo black magic in my head, so I can stand on the shoulders of you guys knowledge and look good, but really still don't understand any of it beyond the fundamentals.

 

[stingray719]

Great feedback.

Clutching is voodoo black magic in my head, so I can stand on the shoulders of you guys knowledge and look good, but really still don't understand any of it beyond the fundamentals.

What you have looks great, just might have secondary wound a little tight. Remember, these sleds gain a bit of RPM as they break in, Girlfriends I had to add weight (at 500 miles now) to get it off the rev limiter (8FS weights added additional weight up to 4 grams). Just note if you are ok now and hit rev limiter at around 200 to 300 miles that is normal just add more weight preferably on the tip.

 

[Reaper]

Gents, why a 5mm spacer on G-W-G spring? I have been hearing 1-2mm?

 

[stingray719]

Gents, why a 5mm spacer on G-W-G spring? I have been hearing 1-2mm?

2mm to 4mm for most. I like to run 6 mm kind of a preference. Try 4 mm and then 6 mm see which you like.

 

[Reaper]

Does adding the spacers just increase spring pressure? What is the effect when increasing thickness of spacers?

 

[wavemaster]

It would just add more pre-load to the spring.

 

[stingray719]

Does adding the spacers just increase spring pressure? What is the effect when increasing thickness of spacers?

On every other Yamaha I have owned putting a shim in just increases take off RPM, but on the Viper due to reasons too lengthy to post here it will wake your Viper up. Check "Clutching on the cheap" thread in FAQ above for full details.

 

[NOS-PRO]

Does adding the spacers just increase spring pressure? What is the effect when increasing thickness of spacers?

Reaper - The spacers (shims) move the entire rpm range, bottom and top to desired feel and performance. Also makes the primary work the way it should.

Thanks wavemaster great post

 

[NOS-PRO]

A little tidbit....if you want more low to mid range, (especially for mountain, powder riding and off trail) i would go with the 4mm or 5mm and wrap the secondary tighter. This will concentrate more power down low as top mph isn't really important. Plus, it raises the engagement.

For trail and us flatlanders who want great performance through the entire range, use 1mm or 2mm (2mm seems to work the best for me) for great pull corner to corner and top end mph, plus a lower engagement that is smooth and increasing mpg because it's pulling more with less throttle.

The shims will raise or lower the rpms on top and bottom.. depending on thick or thin total spacing.

 

[sxr70001]

Thanks again NOS, can't wait to try mine out. Since, I'm not a drag racer I am most interested in the smoother take off and lower cruising RPM, but would also like a little better top end. We will see soon.