Clutching on the cheap

[Alsim]

Add 3.2g to middle hole. Then you will be at the same point I was at the end of last year. The rev limiter is killing your top speed if you hit it you lose speed quick.

Thanks shagman
+ 3.2 gr in the middle wow! Whit how many shims and wrap. ?

 

[shagman]

That is the only change. One change at a time. Make a couple runs and adjust again if needed. Putting weight in the middle doesn't change top rpm as much as tip but will affect it some and help overall. Watch your rpm's, the goal is to get them to come in at about 8650-8700 and climb to 8950-9050 and hold there, but first we need to have enough weight to get it off the limiter then remove some if we have to. this should be real close.

 

[Alsim]

Make sens ! Thanks a lot .
I will try . Actually the rpm goes right to 8600 at lunching and push hard. I hope the additional weight in the middle will not decrease rpm too low at lunching.

 

[stingray719]

Thanks shagman
+ 3.2 gr in the middle wow! Whit how many shims and wrap. ?

Adding 3.2 grams should drop RPM by about 600 rpm...if you need to drop that much. Roughly figure 200 rpm for each gram.

 

[shagman]

Doesn't drop that much at lower elevation in middle hole. That is where I was at last year.

 

[Alsim]

I have in my box 3x3.6 gr and 3x2.4 gr ....hummmm
More weight and more shims or less weight and less shims. At the end the rpm at wot will be probably the same depends how many shims ..but what is the best for acceleration and hole shot ? I have trouble to understanding the difference of both ??

 

[stingray719]

I have in my box 3x3.6 gr and 3x2.4 gr ....hummmm
More weight and more shims or less weight and less shims. At the end the rpm at wot will be probably the same depends how many shims ..but what is the best for acceleration and hole shot ? I have trouble to understanding the difference of both ??

More shims better low and mid, less shims for more top end. I would suggest 4mm or 6mm.

 

[NOS-PRO]

I have in my box 3x3.6 gr and 3x2.4 gr ....hummmm
More weight and more shims or less weight and less shims. At the end the rpm at wot will be probably the same depends how many shims ..but what is the best for acceleration and hole shot ? I have trouble to understanding the difference of both ??

Alsim - What wrap are you at right now? Just want to make sure you aren't slipping the belt.

I would try Shagman's idea....but put the 3.6 gram rivots in that you have. If you like, you can always take a small drill later on and drill a very tiny hole thru the 3.6 gram rivot if needed. Thing is to get it off of the rev limiter

 

[Alsim]

Hi Terry

My wrap is 3-3. I didn't notice black strip on the clutch or belt dust. The belt goes up between 3/8 and 1/4 inch of the top. I think is because I hit the limiter.
I will try Shagman's idea for +3.6 in middle hole and Stingray's recommandation to go with 4 shims. May be return to 6-1 wrap to make sure that I have enough rpm for hole shot and mid ??

 

[stingray719]

Hi Terry

My wrap is 3-3. I didn't notice black strip on the clutch or belt dust. The belt goes up between 3/8 and 1/4 inch of the top. I think is because I hit the limiter.
I will try Shagman's idea for +3.6 in middle hole and Stingray's recommandation to go with 4 shims. May be return to 6-1 wrap to make sure that I have enough rpm for hole shot and mid ??

I have had the best luck at 3-3 on the secondary. 6-1 I get too much track spin.

 

[Alsim]

I confirmed I have good luck with 3-3 wrap. I tested with my bud 1200 doo ( Had 3.6 gr and 2 shims ,9-1 wrap) My Bud had 2 lenghts on hole shot and I didn't cach him . Hit the limiter near 90 mph.
Yesterday with 4.5 gr and 4 shims..3-3 wrap, I had 2-3 lenghts on hole shot and he went to me only when I hit the limiter. I removed 2 shims and the result was the same.

 

[NOS-PRO]

Hi Terry

My wrap is 3-3. I didn't notice black strip on the clutch or belt dust. The belt goes up between 3/8 and 1/4 inch of the top. I think is because I hit the limiter.
I will try Shagman's idea for +3.6 in middle hole and Stingray's recommandation to go with 4 shims. May be return to 6-1 wrap to make sure that I have enough rpm for hole shot and mid ??

Yes, try the 3.6 and go to 4 shims. This will get you real close to what your looking for.

Try the 6-1 first....you can always soften up a little

 

[Alsim]

Thanks all for the advises....I will post my observations and result ! I start to love my viper !!!

 

[stingray719]

On the COTC To clarify,
Set shims to your preference for your riding style:
More primary clutch shims = better low and mid range (more yank your arms on acceleration) - 4mm to 6mm
Less primary clutch shims = better top end speed and upper range - 2mm to 4mm

Start adding weight to the tip of the 8FP weight until you are off of the rev limiter:
Some have ran the weight empty, low miles or that odd machine may use this (not common)
Most run 3.6 gram rivet in tip for sea level, but your machine may vary (most common)
If you need more weight after a 4.5 in the tip add weight to the second hole (not common)

Above 10k altitude (not common) cut 8FP down to 58 grams evenly on the underside of the weight (at your own risk)

 

[Blue Dave]

Well guys I have to say that I am very happy with the COTC set-up on my 2015 RTX DX! I have the GWG primary spring with three 1 mm shims, the 8FP weights with 3.6 G rivets in the tips, a Black Diamond Xtreme 46/40 helix with the stock secondary spring wrapped at 70 degrees. I had BDX cut the spring pocket 0.080" deeper to eliminate coil binding.

The only other mods to my sled are a MBRP race can and 135 studs down the middle. I was only able to test the COTC set-up on the lake last weekend since there is no snow around here for trail riding. It engages very smoothly at around 2800 rpm. When racing from a dead stop it launches hard at around 8700 RPM and climbs steadily to around 9,000 rpm topping out at around 100 mph.

I only had a 600 doo and a 700 poo to race against which was not much of a race. Both had studs and said that they launched with minimal spin (just like me) but I got them both out of the hole and just continued to walk away from them every time we raced. We tried rolling starts but the result was the same.

I have two buds with 800 doo's that will be much better competition. However now even the lakes around here have no snow so I will have to wait for that test. Thanks again for all of the help guys. This is what makes TY such an awesome site!