yamadoo clutching questions

[Turbo11T]

Ok I have a yamaha vector motor in a rev chassis. I was having what I thought was problems with the motor or turbo setup. And Now I think I have found out that the clutching was not even close to making it work right.

Here is my current setup.

Primary spring blue/pink/blue
8bu-00's Fully loaded
14.5 rollers
engagement 3400-3600

Team Secondary
44 degree helix
180/300 spring Black/lime Green

Running the doo belt.

What can I do to increase the engagement rpm?

Questions on secondary

1. If i lower the spring rate what will the result be?
2. If I lower the helix degree what will the result be.

I am not a clutching guru. Last year I ran the same setup with the stock yamaha secondary with a Cat green spring and a shockwave helix and it worked perfect but this year I have the engine compression lowered and it is not quite as strong on the bottom end. And I can't run the yamaha secondary yet . . . . . I am working on building a new jackshaft to run the yamaha secondary on the ski doo.

 

[SylvanLaker]

If you want it to engage later you need a stiffer starting spring rate in the primary spring. Usually its better to engage earlier as it is smoother. Also it usually saves fuel on the trail.

If you go to a softer secondary spring i would suspect your belt will slip causing a lot of heat. We usually use the stiffest secondary springs and put at least 120 degrees of preload in them. mind you this is in a Yamaha secondary. but the principle is the same across brands.

What exactly is the issue anyway with your clutching? Was this the sled Jeff at Quantum Built?? JC..

 

[bdoe22]

SHIMS

YOU CAN ALSO SHIM THE SPRING IN THE PRIMARY TO RAISE ENGAGEMENT SLIGHTLY. UP TO THREE SHIMS. ~ 100 RPM PER SHIM.
YAMAHA PART #
90201-483P9-00 $6.35 EA.

THE SOFTER THE SECONDARY SPRING THE FASTER IT WILL SHIFT OUT, AND THE SLOWER IT WILL BACKSHIFT.

THINK OF THE HELIX ANGLE AS LOAD ON THE MOTOR. THE HIGHER THE ANGLE, THE MORE LOAD YOU PUT ON THE MOTOR.

 

[Turbo11T]

I talked with Allen Ulmer and he was very helpful to what I wanted to know. It sounds like for every 5 kg of preload I can expect to see aprox 300-400 increase in engagement rpm. I would like to increase 800-1000 rpm in the engagement I think. I would really like to see what that does. I have a green/white/green spring here I can try to see if I like the engagement rpm. I don't think I will care for the finish load that that spring has though. I will order a blue/white/blue if I like where I get my engagement to. That spring should be higher engagement but close to the same finish as the current spring I am using.

It also sounds like I may be able to get away with a little lower helix angle if I decrease the spring a little.

I am going to try to make the sled work with the team clutch for now and I will start working on a new jackshaft for the yamaha clutch again.

 

[BigFish BC]

i ran blue white blue primary spring with supertips at around 75gram 14.5 mm rollers & a purple cat spring wound 1-0 with a 47-49 degree helix in my vec worked perfect.

 

[Turbo11T]

i ran blue white blue primary spring with supertips at around 75gram 14.5 mm rollers & a purple cat spring wound 1-0 with a 47-49 degree helix in my vec worked perfect.

Yeah I am thinking that the blue/white/blue spring is the one I need. It will give me the higher engagement i am looking for and the the finish rate I need.

 

[Wheel House Motorsports]

thats almost the identical setup i run on mine, just i rock the gbg spring and loaded 8bu;s but identical secondary.. rollers. etc. works awsome and engages just over 4k.

 

[Turbo11T]

I have it figured out. It is all clutching related. I put a higher engagement spring in it and it is far better. The only spring I have right now is a green/white/green. So it has a kinda high finish. I am going to order a blue/white/blue and that should get me right where I want to be for the primary and then I will play with the secondary.

I never thought it could be the clutching. But I guess with the changes I made this year i really needed to make changes to the clutching.

 

[Wheel House Motorsports]

yeah, if the clutching is off, its definately gonna kinda suck.... get that dialed in and see where your at.

 

[BigFish BC]

i think you will find you will like a little steeper helix too later the steeper you go the harder it will pull off the line. i ran a 51 for a long time but liked the 49 better.

 

[Turbo11T]

As far as the helix goes i think that it being a team clutch It must not react the same for the helix number as the yamaha clutch. I had a 48 in it and it wouldn't pull the rpm and was sluggish. Now the 44 feels very good.

Stupid question. Is a 44 steeper than a 48? How does that work? I guess I have never understood where the angle is measured from. I actually was thinking of going to a 42 and a little lighter spring in the secondary.

 

[philsummers21]

Id stay with the 44 in the TEAM.

 

[Turbo11T]

Id stay with the 44 in the TEAM.

Do you have any real world knowledge running the team on a turbo yamaha? If so please share. If not can you tell me your logic with not going to a 42. There are not many running the team on turbo yamaha's and the ones who are haven't shared much. I am just trying to learn. I have ridden ski doo for years and I have learned more about yamaha clutching in the past two days then a ever new about the TRA. Yamaha primary is stupid easy to understand.

Thanks in advance.