Using a polaris primary on a doo

[glassman]

I am getting mixed reviews from guys regarding using the p85 on a rev. Has anyone been running a polaris primary on their rev's with what kind of results? I hear stories of crank failure and inefficiency, could this be true? Someone please enlighten me.

 

[Tackbtch]

Short of haveing to relace my TRA I wouldnt doo it. I get great shifts and long belt life, 5000 miles on my02 and no problems. Fairly simply to work on, keep em clean and they have a great service life. I dont know of any Pol clutchs on a Doo but both my boys run them on there 900 Cats with good success. Dino

 

[Bigdog Racing]

I run an P85 on my Pro Stock 800 Mach Z drag sled....This is a very common swap with race sleds.
You will need top have the taper recut on the I.D of the primary for the proper crank stub size.
Depending on which P85 you use, you may be able to use your stock primary bolt from the Rev.
And also you will need to have a puller machined for clutch removal.

P85 are far easier and cheaper to tune....they are bulletproof...and make great efficiency.....A MicroBelmont is very similiar to a P85 in design....Adjustable sheave cover and extra posts.

Call Gary at Micro-Belmont...He was extremely helpful....He sells the pullers and can recut the taper....He can help you with a belt, and let you know about adjusting your offset.


Bigdog Racinng

 

[revrider]

The thing I have heard is they are harder on cranks because the Doo clutch has a rubber hub to suck up the vibes. I agree with keeping them blown out and they relly last.

 

[glassman]

Does Anyone have any first hand knowledge of someone actually breaking a crank or causing any dammage, or are we relying on hearsay?

 

[Bigdog Racing]

Personally....I have never heard that....
It is a very common swap we do with race sleds that generate well over 200hp.
Call Gary at Micro-Belmont....He is a wealth of knowledge and he machines the tapers as well as makes the proper puller.

Bigdog Racing

 

[winter brew]

I have known of several guys to lose cranks with a P-85 on a Doo, but this was "back in the day" when we ran 670's and the TRA was a bigger diameter and alot heavier. Now the TRA is similar in mass to a P-85 so I would think the effect on harmonic changes would be less.

 

[towny]

I have known of several guys to lose cranks with a P-85 on a Doo, but this was "back in the day" when we ran 670's and the TRA was a bigger diameter and alot heavier. Now the TRA is similar in mass to a P-85 so I would think the effect on harmonic changes would be less.

TRA 7 with e-start ring gear weights 12lbs on cheep (bathroom scales)
P85 with no ring gear weighs 7lbs! Not near the same mass!

Mine vibrates real bad at 5600-6500 rpms.
Gona build a disk and bolt it to the back side of the P85 so I can add the Ski-doo ring gear. (Miss my e-start!)
Should add aprox 5lbs to the P85 when done. Then re-balance.
Hope it works cause the P85 works real good!

 

[winter brew]

TRA 7 with e-start ring gear weights 12lbs on cheep (bathroom scales)
P85 with no ring gear weighs 7lbs! Not near the same mass!

Mine vibrates real bad at 5600-6500 rpms.
Gona build a disk and bolt it to the back side of the P85 so I can add the Ski-doo ring gear. (Miss my e-start!)
Should add aprox 5lbs to the P85 when done. Then re-balance.
Hope it works cause the P85 works real good!

I havn't weighed them, most guys using the P-85 on a Doo run a ring gear. Bad choice of words maybe....they are not "similar" in mass, but they are closer in mass than the heavier/larger diameter TRA of old.

 

[glassman]

So no one has heard of a p 85 on a rev? Mountain magic says they sell loads of them yet I havent seen one!

 

[Summit8]

Mech working on one of my sleds said the same, of p-85's being hard on crank bearings.

P-85 easier to work on than a TRA?? WTF with that?? LOL

 

[TVC 15]

Not a good choice for a trail sled. Like others have said the p85 is to light and it will vibrate like a mofo. But hey opinions very.

 

[towny]

500+ miles on my P85 after re- balancing on my 07 800r 151 and So far so good!! In fact really good!! Very impressed!! Vibes are no more than stock with the TRA7. Unbelievably cool clutches! Wished I'd have done this years ago!!

 

[TVC 15]

With reguards to towny your p85 has a starter ring on it. That would add mass and should help tame down the vibration.

 

[towny]

The brass ring (Actually it's bronze) not only acts as an adapter for the Ski-doo starter ring, but I also machined it large enough to add mass so the total weight is about the same as the TRA.
It vibrated fairly bad before I added the starter and adapter ring but it also vibrated just about as bad after it was installed. I had the whole assembly re-balanced and it took care of the problem.

I don’t know for sure, but if I would have had the P85 re-balanced before I added the adapter/starter ring, that it would have made much difference in vibration??? I wanted to use my e-start that’s the main reason the adapter rings there.
A friend has a 06 900 Poo and you know how bad they vibrate!! The end of the crank broke off right where it goes into the case. They started it at the dealer when he took it in to get fixed and “He Said” it ran really smooth??? Sooo maybe the P85’s aren’t balanced very good from the factory??

 

[glassman]

towny, did you buy a p85 and have it machined, or was it built for a doo before you bought it? I have one sitting here in a box but I am hesitant to use it. Especially since i dont have a ring gear on it.

 

[BIG JOHN]

P-85 for a DOO

I have 1 brand new big bushing P-85 cut for a DOO taper for sale...$395 shipped-BJ

 

[rockymking]

You got PM BJ

I have 1 brand new big bushing P-85 cut for a DOO taper for sale...$395 shipped-BJ

Interested......PM'ed ya.

 

[prototype69]

Towny, i am curoius who balanced the clutch for you and what spring and weights are you running?