Anybody ever messed with a p-85 primary?

Backwoods M Max

Backwoods M Max

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I know tom Hartman sells and recommends the p-85 on Yamaha motors for tuning ease but if you ask me its inferior to the yvx primary design. Anyways. The p-85 in my 99 indy needs a rebuild. It was rebuilt by the previous owner about 3000 miles ago but the lazy shop didn't tear it down to change the rollers. It had a borderline roller that is completely failed now and it wiped out the weight bushing.

Anywho has anybody done a complete tear down on a p85 themselves? The holding plate and all wrenches runs a few $$$ before even adding parts. Anybody have a ballpark idea what a tear down to do rollers and sliding pads runs? Weighing the tools for a 1 time job vs having a shop do it.
 
This was one of the best clutches in the industry. There is a reason it is so popular for racing. However, they do have a few downsides. Once they are allowed to wear too much due to lack of service (which is what yours sounds like) it is time for new sheaves as they usually incur damage. Generally better to just find a good used one. If you do rebuild make sure the towers haven't suffered any damage. Once the bushing, etc. wear the sheaves make contact at the towers.

If yours is okay and you buy the parts to rebuild, you should find someone to rebuild it (and do a good job) for under $100. If you do it yourself, just build what you need unless you are going to do a number of them.

If you do look for a used one, make sure you get the P85 and not the P90 (different angle and much lighter duty).
 
^^x2 just build your own tools much cheaper. Price of rebuild kit depends on what brand you use. We the EPI kit on my dads ultra a few years ago and it was almost $200. I would use it again if I had to do another p85.
 
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This is what we're up against. It's just one roller out of 3. The guy I had in mind is an independent and has a stellar reputation. It's from a 99 700, which from what I found out has its own crank taper for the 97-99 domestic big block twins. I'll let him tear it down an make sure nothing is fatal inside. Buttons look good, it's just the damn roller that's messing everything up. The engine was rebuilt around 3000 miles ago and had the crank bearings upgraded and supposedly the clutch was balanced so I would like to keep it on the motor if I can. I'm definitely disappointed that you can't change rollers like the yvx but for a couple hundred I'll let Harry's keen eye look it over as the is quite the possibility of me missing something from lack of experience with them.
 
Im going to bet the weight and roller gouged the heck out of the spider by the looks of it. If so, if it was balanced, its not anymore. It may still be useable though depending how bad it is.
As far as oem clutches go, Polaris are probably the best out there especially when it comes to tuning. Parts are plentiful and inexpensive vs Yami clutches which are good, durable, clutches, however tuning parts are limited and expensive. Also they dont interchange with any other parts like Cat, comet, and polaris clutches do.
 
Yah, that looks like it likely damaged the spider. Yes, I meant to mention about the taper. I would start looking for a used replacement.
 
I have a p85 that was on my mm if you need one for parts or something. Likely the weights or whatever are different than what you'd need for that sled tho.

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The first time the weight jammed was on the stand after cleaning the secondary so I'm hoping nothing bad has come of it yet. I'll let Harry get into it and let me know what he thinks. Not super psyched when I found out about the 97-99 domestic twins being different it really limits what I can look for.
 
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