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Lightweight clutching questions

RanOutofTalent

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Got my first 850 this year after being on the 800 for many seasons.
I have a buddy who convinced me to get the
ZRP lightweight kit and send in my rotor and flywheel. I am also going to have the clutches balanced by Patrick’s.
I ride in western Montana 7-9k, 10 on occasion.


My questions would be:
1. Anyone have suggestions on changing out the primary spring to say a blue/pink and the secondary to a team black? Or is stock a team black?
Add a Derlin washer or is the the same a the hardened clutch shim??


Coming off the 800 this what I used to do.

2. Where does the hardened clutch shim in the kit below go?

3. Anyone lighten and balance their 850 clutches through Patrick’s last year and have any feedback?

I was going to just send for balancing and was curious if the very small 567g on the primary and 370g on the secondary is worth the extra money.

Any advice is appreciated.
Let it snow!!!



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revrider07

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For all out performance looks to be a good mod. Life of crankshaft I would think not so good
 

goridedoo

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I know very little about it, and not here to argue.

They say the lighter your primary the more harmonics/vibration you will have. How much will it actually effect crank life? No idea. I would THINK a good balance will make up for most of what you “lose”.
 

RanOutofTalent

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I know very little about it, and not here to argue.

They say the lighter your primary the more harmonics/vibration you will have. How much will it actually effect crank life? No idea. I would THINK a good balance will make up for most of what you “lose”.

I didn’t think ya were. I appreciate the response. I was more curious is all.



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LPIdaho

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Got my first 850 this year after being on the 800 for many seasons.
I have a buddy who convinced me to get the
ZRP lightweight kit and send in my rotor and flywheel. I am also going to have the clutches balanced by Patrick’s.
I ride in western Montana 7-9k, 10 on occasion.


My questions would be:
1. Anyone have suggestions on changing out the primary spring to say a blue/pink and the secondary to a team black? Or is stock a team black?
Add a Derlin washer or is the the same a the hardened clutch shim??


Coming off the 800 this what I used to do.

2. Where does the hardened clutch shim in the kit below go?

3. Anyone lighten and balance their 850 clutches through Patrick’s last year and have any feedback?

I was going to just send for balancing and was curious if the very small 567g on the primary and 370g on the secondary is worth the extra money.

Any advice is appreciated.
Let it snow!!!



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1. SLP's spring recommendations have been spot on lately, recommend the change. Stock is the black spring in the secondary.
2. Between the spring and the clutch cover.
 

LPIdaho

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Can you explain how you believe this lightening the clutch and balancing would affect the life of a crankshaft? This does not make sense to me.
It could be getting better or it could be getting worse. There is no way to know without having the spring constant of the crakshaft and the unbalance of the mating components. Without that information, they are just making a coin-flip guess at best.
 

Reg2view

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Harmonic impacts are unpredictable on a specific motor without blueprinting the entire motor. Individual motor and model specific. OEMs have been providing hand machined lightened, balanced primaries, e.g., for many decades via the race shops. Works of art. Ran them myself back in the day. Side-by-side they are more responsive. These motors are blueprinted and routinely torn down. If your crank is out of phase, and most OEM mass produced cranks are, or bent at all, the harmonic impact can be significant. Doo 800 HOs were notorious for being out of phase 1-3 degrees. They didn't care, just make it through warranty with a heavy primary. We've all seen the hot stocker, that just repeatedly beats identical motors, pipe, and clutching with no blueprinting of the chassis or motor - in phase and straight crank are often the reason. Shouldn't stop anyone from doing it, just recognize the bill could be higher than buying and bolting. Great to have choices, and nothing wrong with seeking marginal gains. JMPE.
 

revrider07

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Reg has a good explanation of it. I've been very careful about taking weight off end of cranks on something I'm depending on getting me home. At the racetrack it only has to last a small amount of time tear it down and start over. I have broke several lightweight cranks for Polaris 800 trying to squeeze every oz of performance out. Just my observation your miles may vary.
 

carbontj

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We have been doing light weight clutches for 7 years. my very first carbon fiber cover, and balanced was sent to Polaris in 2011 to be run on their drive line endurance dyno..Engineers thought it would last 20 hours..After 100 hours straight they pulled it off and found very little if any wear on the bushings, rollers, and weights...did the balance do it? or was it the softer material of carbon fiber absorb the harmonics? or was it going through the harmonics faster?? The engineers all where very pleased..the biggest issue with cranks is inertia..what kills a crank is reving the motor and stopping instantly!! Lighter weight helps inertia as well..
 

madmax

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Everyone is doing it, so it must be good, right!?!? I know a lot of guys who run the crank light weight ZRP stuff, never heard of anyone having a crank problem. Ive heard it argued both ways, that a lighter crank will cause future problems secondary to harmonics and Ive heard the race guys who swear the light weight crank is beneficial in the butt seat dyno. It would take a lot of time and money to prove one theory is right. If anyone has some real world proof one way or another I hope you share it.
 

RanOutofTalent

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I appreciate all the feedback as this is a learning experience for me.

What got me to spend the time and money on this was a buddy that had the lightweight kit, machining and balancing, new springs and performance clutch weights completed last season. It was hands down the best mod to a sled for the money. It was night and day difference to a stock sled. It woke the sled up on a whole new level.

So for the $800 I am happy to spend it as I won’t need a gear down kit. I am hoping it ends up being worthwhile.


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b-litt

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I put 2,400 miles on my 800 axys three years ago running Patrick’s package. The motor went down at 2,700. Slp pipe and can were the only other performance mods. I have about 4,000 combined miles on two other sleds since then that both have the Patrick’s primary and secondary done. They still run great. One 850 and one 800.
It doesn’t look to shorten the life of the motor in my experience with my sleds. And the throttle response is improved significantly. The light clutches with a gear down will make for a snappy sled.
I’ve never tried the zrp rotational items. I’d like to, just never take the time before snow flies to send them in.
 
S
Dec 16, 2011
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I don’t know about the crank life but I run an Indy Dan heavy clutch cover and it sure smooths out the motor I tried a lightweight cover for a few rides not carbon fiber and couldn’t believe how much more the motor shook especially at idle.
I am curious about the carbon fiber cover though and wonder if it doesn’t absorb the vibration unlike aluminum?
 

carbontj

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I don’t know about the crank life but I run an Indy Dan heavy clutch cover and it sure smooths out the motor I tried a lightweight cover for a few rides not carbon fiber and couldn’t believe how much more the motor shook especially at idle.
I am curious about the carbon fiber cover though and wonder if it doesn’t absorb the vibration unlike aluminum?
We believe it does..it is softer material and will stop vibration for returning....I know for fact and Polaris does to, that our carbon fiber covers and balancing will help the life of the clutch..If it does that it will help the life of the motor.
 
K

klarkkentster

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Apr 22, 2020
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I appreciate all the feedback as this is a learning experience for me.

What got me to spend the time and money on this was a buddy that had the lightweight kit, machining and balancing, new springs and performance clutch weights completed last season. It was hands down the best mod to a sled for the money. It was night and day difference to a stock sled. It woke the sled up on a whole new level.

So for the $800 I am happy to spend it as I won’t need a gear down kit. I am hoping it ends up being worthwhile.


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Well - how much did you like it? I just sent my to Patricks as well and UPS says it will arrive Saturday. Can't wait. I also did the ZRP stuff and had TJ add a couple of other lightweight mods as well.
 

indydan

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The crankshaft in all 800 2016 thru 2021 are to light so no lite-weight clutch parts should be used( adding weight will making clutch and crankshaft life longer ( Ask TRSTony )

850 same deal, crank is to lite..... lite-weight clutch componets are a bad idea

adding weight is much better plan.

Thats why our clutch covers are so heavy duty, long life and dependable.


Dan
 
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