Clutching help

[skidooslayer687]

Sorry for all the questions just trying to understand these weights a bit better

 

[kviper]

It generates more centrifugal force as soon as the clutch engages, squeezing the primary closed faster, shifting up faster and pulling the motor harder.

 

[kviper]

Sorry for all the questions just trying to understand these weights a bit better

No problem!

 

[newtron]

Yes 46 to 48 is more cam, shift harder, lower RPM.

Do you find with a big split on a multi angle helix (say 50/40) that your rpms start at your target rpm, drop down and then climb back up to target rpm?? This is what I have found but maybe just require more secondary tuning

 

[newtron]

Or probably just a traction issue!!

 

[kviper]

Do you find with a big split on a multi angle helix (say 50/40) that your rpms start at your target rpm, drop down and then climb back up to target rpm?? This is what I have found but maybe just require more secondary tuning

No I can't say that I have. The angles change progressively for the most part so if theres a change due to cam it should be progressive.

 

[kviper]

No I can't say that I have. The angles change progressively for the most part so if theres a change due to cam it should be progressive.

Are you sure you're not seeing over shift?

 

[newtron]

Are you sure you're not seeing over shift?

Ya probably spinning.

Thanks for the info. Clutching can drive you crazy sometimes

 

[kviper]

LOL, over shift from traction issue!

 

[skidooslayer687]

So is it as simple as just loading the heel until the over rev is gone? That seems a little to simple lol

 

[newtron]

yes I think its best to control rpm at the primary first

 

[kviper]

So is it as simple as just loading the heel until the over rev is gone? That seems a little to simple lol

Yes but it will also effect your shift RPM some all the way through. You may need to pull some from the tip. It's not a one to one relation ship though. It takes more weight to drop 100 RPM on the heel than 100 RPM on the tip. It's always multi faceted with snowmobile clutching.

 

[stingray719]

Funny to see guys that don't own a Viper trying to set them up, because we all know the Viper sets up different. Weight profile has everything to do with your RPM on takeoff. The original weights in your Vipers (non MTX) had a hump in the base to deliberately cause an overrev....yeah I know why do that? Now, I do not know what profile weight Ullmer is running nor do I know what Dave is running....I can only tell you to ask the guy you got the kit from as all the parts are designed to work together. I.E. Running our GWG spring from our "clutching on the cheap" thread isn't going to work for your weights as it does for the 8FP we set it up with. NOS-PRO Viper that in the real world turned 11.2 at 109mph in the 1/4 mile on asphalt with only a can and my air box mod...and my clutch mod, most of it in the clutching. Our Red Viper with air box mod and clutch mod runs even up with our friends 800 Ski Doo. I have never seen a Yamaha that you can get so much out of in the clutching.

And changing the secondary spring effects your setup also as far as upshift and backshift and even a little RPM. What I am saying is don't go crazy trying to reset a kit you bought, call the guy you got it from.

 

[STAIN]

Also be careful trying to set up your clutches in low/no snow conditions. If you are spinning the track out on hard dirt or short bursts on your lawn you are going to get over rev and hit the limiter. It will act different on snow and trail conditions. Traction will pull the RPM's down.

 

[Stubbs]

Funny to see guys that don't own a Viper trying to set them up, because we all know the Viper sets up different. Weight profile has everything to do with your RPM on takeoff. The original weights in your Vipers (non MTX) had a hump in the base to deliberately cause an overrev....yeah I know why do that? Now, I do not know what profile weight Ullmer is running nor do I know what Dave is running....I can only tell you to ask the guy you got the kit from as all the parts are designed to work together. I.E. Running our GWG spring from our "clutching on the cheap" thread isn't going to work for your weights as it does for the 8FP we set it up with. NOS-PRO Viper that in the real world turned 11.2 at 109mph in the 1/4 mile on asphalt with only a can and my air box mod...and my clutch mod, most of it in the clutching. Our Red Viper with air box mod and clutch mod runs even up with our friends 800 Ski Doo. I have never seen a Yamaha that you can get so much out of in the clutching.

And changing the secondary spring effects your setup also as far as upshift and backshift and even a little RPM. What I am saying is don't go crazy trying to reset a kit you bought, call the guy you got it from.


Good call. Definitely give the guy that built the kit a call for the most accurate assistance.
BTW, not trying to set up anybody's sled for them over the Internet. Just sharing advice I've either been given, or seen given out, by great clutch tuners, in regards to every other Yamaha 4 stroke built to date.