Looking for answers to overdrive problem

[UPsledder]

In looking at my secondary it has become evident that I am not making full use of the overdrive. I took out the spring in the secondary and with it fully opened if I seat the belt between the sheaves it is about 3/8" from the bottom which seems to be way to much. Doing the same thing on the primary with it fully closed their seems to be room for improvement as well. A while back I thought someone addressed this issue. If someone has some helpful information I would appreciate it.

 

[vmaxjohn]

There's alot to getting full shift. You'll need perfectly groomed HARD snow to ever see it, and it'll take a mile or two for your sled to hit its mechanical limit.

Mark the sheaves with a broad stripe from a magic marker, starting from the edge and running to the center. Take it for a spin in your typical condition, and see how far you shifted out. If you're in loose snow, you'll probably never see full shift out, since the clutches are forced to run in a lower gear, or bog the motor.

Is this a trail sled, race sled...? What do you want it to do?

 

[UPsledder]

John I appreciate what you are saying but I opened the sheaves on the secondary as far as mechanically possible and with the belt seated as deeply in the sheaves as possible the bottom of the belt was 3/8" above how far it should go thus effectively eliminating the overdrive. I did however shim the helix about an 1/8" out with some washers and by doing this could effectively spread the sheaves enough to get the belt within about 1/8" from the bottom which I think would be a good position to be in when shifted out. I think Yamaha has left a lot on the table here but both the primary and secondary have to shift out together to attain this. In checking the primary I am convinced that it could shift out further if the secondary would mechanically allow it to. I am sure someone has a cure for this somewhere.

 

[Buckeye]

Secondary overdrive

Most of the aftermarket helixes come with the inner hub cut to allow the secondary to open further. This however will not make the belt rise higher in the primary. To do that you either need to machine your fixed sheave or buy an overdrive sheave which will allow the belt to ride to the top because the sheave tops come closer together.

 

[1xr]

Would spaceing out the helix with washers have an effect on the spring side force and twist?

 

[UPsledder]

Buckey. Would you happen to know who might have an overdrive sheave available? That sounds like a good approach. Thanks. 1xr I wondered about the spring pressure as well. Thanks you guys for your imput.

 

[Buckeye]

Over drive

The effect on the spring would be minimal, but you could increase the twist 1 position to offset any effect,

Here is a link to Hauck's overdrive sheave:

http://www.hauckpowersportsinc.com/Page18.htm