Yamaha Extra Ratio Clutch

N

NorthofSixty

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Nov 22, 2011
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355
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Yellowknife, NWT
The 92 Venture VT480 LT I picked up last weekend has an Extra Ratio Clutch. Never saw one before and not much info on line. Is this just a larger diameter secondary and does it require a longer or wider belt than the Phazer or regular Venture?

I assume with only 485cc they needed to improve the low end torque to drive the 136" track without burning up belts? If anyone has any in the on this clutching system it would be appreciated.

Thanks
 
Bigger diameter primary and secondary which gives a lower starting gear so to speak and an overdrive vs. the YPZ. Runs a 1-3/8" belt. Current OEM part number 89L-17641-01-00
 
Any idea of how well it performed as compared to the standard clutching used on the earlier models. I am thinking about swapping out the standard clutches on the 91 Phazer ST with the over ratio system from the 92 Venture. Both are 136" tracks.
 
What you will find is more tuning components and much easier calibrations along with better belt life and a few more belt options, but no real noticable gains in performance.

The biggest issue you will find swapping ypz with yxr is that the 91 and earlier have a different oil pump drive housing than the 92 and later. So, the 91 clutching will leave an air gap(oil/grease leak spewing on the clutch) at the pump drive and the 92 and later clutches wont fit a 91 or earlier due to the diameter of the hub on the backside of the yxr clutch unless you swap the pump drive housings.

The pre 92 use the 8VO housing and the 92 and later use the 89F housing. All the guts are the same, its just a different housing and seal to run the updated clutch. With the 89F housing, you can also run the modern clutches giving you even more tuning options.
 
Thanks, Good to know before I got too deep into swapping parts. Fortunately I can swap the entire pump housing and clutch from the 92 Venture over to the 91 Phazer and retune it if necessary. I am running a stock pipe and carbs and gearing for now so it may not need much tuning.
 
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