Anyone interested?.....

[Srxspec]

Guys, I'm currently looking into having a billet aluminum over-sized secondary made that will utilize a stock Yamaha style helix, but will be 13" in diameter. What this would allow you to do is leave your sled geared for higher top end, but it would give you the bottom end of lower gearing. The kit would consist of a secondary and belt as a package. This is something that could become a reality with some interest. I'm looking to keep it roughly the same rotating weight as the stock secondary and making the adjusting for the belt width on the outside of the secondary so it's easily accessible. Pricing would be in the $400 range for everything needed! Let me know if this is something that interests anyone. Would be trail, mountain, or race ridable.

Allen

 

[LazyBastard]

Wouldnt you also need a bigger primary for that? I assume that the belt that would come with the package would be a longer one that would be able to make it to the outside of the new secondary. That being the case, in order to shift out to stock final ratio, you would have to take up the belt slack with a bigger primary.

???

 

[Srxspec]

No need for a bigger primary, the stock primary ratio will still allow it to shift out fully. It's a different length & width belt. It will come with different split collars for behind the stationary primary sheave.

Allen

 

[LazyBastard]

Ok, you mean using the extra 1/4" on the outside by using a wider belt?

 

[Srxspec]

The belt is a Polaris belt which is longer and has a different width as well which makes up for the added diameter of the secondary and allows full shift yet.

 

[black john]

bigger

thats an exelent mod ive done this before on my older sleds and it works very well. the trick is finding the right belt. by doing this you get an under drive at its lowest ratio and an over drive in high bouth do the increse in belt width

 

[JDKRXW]

Re: bigger

by doing this you get an under drive at its lowest ratio and an over drive in high bouth do the increse in belt width

It seems to me that you are half right. Wouldn't you only get increased underdrive (due to the larger diameter)..... and the overdrive ratio (shift out) would stay the same?
And wouldn't the additional belt width be needed to make up for the increased circumference change in the larger secondary?

 

[grader]

the overdrive comes from the wider belt riding higher in the primary, which is why it has to be set up with different shims.

 

[LazyBastard]

Except that it doesn't net to an overdrive since the belt will be further from the center of the secondary. It nets to original full-shift ratio (approximately), so it drops the engagement ratio without dropping the final shift ratio. You can change it to a pure overdrive by raising the gear ratio in the gearbox, then it could start in original overall ratio and shift to a higher ratio.