I see on snowest that quite a few guys use the polaris P-85 primary on their Yamaha's. Does anyone know why?
Madmatt
Madmatt
B2SO
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Bender And Hartman Inc. Do The Same Thing ..
yamaholic22
Active member
i did it for the ease of set up, the great bottom end belt force, the efficiency in the last 15% of the shift curve (p-85 is the most efficient of the oem clutches through the upper range), the more completele shift-out, and the ability to run adjustable weights without clutch machining. The last one doesn't really apply anymore, because they now make adjustable weights especially for yamaha clutches. I had good luck with the p-85, but they need to be rebuilt more often than the yamahas.
Efficiency
Yamaholic, that is interesting about the efficiency in the last 15% of the shift range. I am having trouble with my clutch in my 780 Viper. Sometimes the thing just will not shift out all the way. It's like it gets to a certain point and just quits shifting. I think I have tried everything. Do you think it would be worth it to try a P-85? I have the 14.5 rollers in it and I have heard that they loose top end. Thinking about going to 15 or 15.6 but not sure if I will have enought belt squeeze then at the beginning of the shift curve. Any thoughts?
Madmatt
Yamaholic, that is interesting about the efficiency in the last 15% of the shift range. I am having trouble with my clutch in my 780 Viper. Sometimes the thing just will not shift out all the way. It's like it gets to a certain point and just quits shifting. I think I have tried everything. Do you think it would be worth it to try a P-85? I have the 14.5 rollers in it and I have heard that they loose top end. Thinking about going to 15 or 15.6 but not sure if I will have enought belt squeeze then at the beginning of the shift curve. Any thoughts?
Madmatt
yamaholic22
Active member
Madmatt said:
I ran into the same types of problems trying to select roller size as well. I ended up going with 15-15.6 mm rollers and just running a lot more weight in the first hole, and that gave decent belt squeeze at the bottom but still kept the awesome top end. In my piped sx 700r i actually ran the 16mm rollers to keep the engagement nice and high with a lower rate spring, and that thing shocked me with top end, especially with a lot of tip weight and a shallower finish angle. If you run the 8CA's you need 14.5's pretty much no matter what, or it will engage so high and just smoke the belt on the top end. Even with the 14.5's you have to load the tips on those pretty heavily. Not sure if you have ever run those, but they are a great drag weight.
monker
New member
Is there anything special that has to be done to put a P-85 on? How about different belts, or is the yammi belt still what is used?
thanks.
thanks.
yamaholic22
Active member
no nothing special has to be done, the taper's are identical, even the alignment comes almost perfectly. I used both, the 8DN as well as Ultimax 2's. Both performed well, but i ended up using the ultimax because even though they wear out much quicker due to their softer compound, they really grab hard and transfer the power outstandingly. I would still get around 2,000 miles to a belt before it started getting too narrow. Never blew one.