Aftermarket clutch cover reviews

Scott

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Are these both for Polaris or is one for Cat?

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Both are for Polaris P-85 primary.

I didn't ever get around to putting the ER 911 on my primary when I bought it. I did use the happy face on my old primary until It was plum wore out and needed to be replaced. I didn't get around to transferring it to the new clutch.
 

summ8rmk

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Both are for Polaris P-85 primary.

I didn't ever get around to putting the ER 911 on my primary when I bought it. I did use the happy face on my old primary until It was plum wore out and needed to be replaced. I didn't get around to transferring it to the new clutch.
I figured they were for Polaris but this is the Cat forum so, i thought maybe u had Cat parts....

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ullose272

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I was watching you tube and I seen a team clutch come apart with a custom cover on it . I’m not so sure that is the answer.
Why i think it would be important to balance the clutch. Couple grams becomes alot at 8000 rpm

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Scott

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I figured they were for Polaris but this is the Cat forum so, i thought maybe u had Cat parts....

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HAHA, sorry, i didn't even catch what form this was in. Sorry!!!!
 

johnsonracing

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I'm not a fan of the factory bushings like ZRP and Bikeman use. I would look at the 911 or another brand that have a bronze or sintered metal bushing. I know Indy Specialties make a good cover for the Polaris P-85 but not sure about what they offer for cat. Just my .02$.
 

summ8rmk

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I really like the look of the ZRP...
What type of bushing is in there?

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kanedog

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Since the Bikeman cover is built to be a direct replacement the Bikeman Cyclone cover is built to the exact same spec as the original cover as far as stops, spring pocket and tower clearance. The factory stop has an important function to limit up shift. The reason clutches limit upshift is to prevent over shift and over tension of the belt at full shift. Any modifications to the stop would require secondary stop and travel to be verified ok.
Joey, you know better. In no way should the cover EVER be preventing full shift out. If it’s to prevent too much tension on the belt at full shift out, the belt is too short or the clutches are incorrectly designed.

If you are building covers that hit the spider nut before full shift out, you are opening up yourself for liability. I have seen a pic of a BMP cover that has come apart.
The Cat cover/bushing contacting the spider nut to prevent full shift out design is both incorrect and dangerous. Clutches use sheave to sheave contact to adjust for full shift out width, not the cover. If Team is using the cover to prevent full shift, they should have manufactured the clutch different.

Under normal circumstances, your cover may be just fine. When you factor in the Team built in cover interference, mix in a little harmonics and very few covers stand a chance. If it were me, I wouldn’t supply any roller bearing type Alpha Cat primary clutch parts for a 2017, 18 or 19. Maybe the 2020’s after the clutches are proven to last.

I’m shocked that you are not aware of this issue. I’d more expect a convicted criminal the likes of E.L. of old Bikeman to deny an issue to make sales, not you.
I have no affiliation with Thunder clutching but I did install the 911 cover on my Alpha. There is no interference and the clutch will hit full shift out.

The pics are the end result of using a cover to prevent full shift out. It flexes on each full shift attempt and will eventually spit out fatigued pieces if not fully fail. A clutch exploding at 8000rpm is the same as Russian Roulette. I’ve had a clutch explode and I honestly felt like I cheated death. I love Cat but this is some serious chit.

Don’t shoot the messenger. I’m simply demonstrating common sense and real life pictures. The above are my beliefs.

I love your vids and contribution to the site. Please keep up the good work. Cheers

53101CA8-DCB4-4094-85FB-993541774342.png
 

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CO 2.0

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So where do you balance when running the zrp or bmp clutch covers? There is no meat to drill balance holes like the stock cover.
 

ak

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So where do you balance when running the zrp or bmp clutch covers? There is no meat to drill balance holes like the stock cover.
I’m thinking the fixed sheave would get small drill holes.

When I had my Patrick custom carbon Polaris clutch balanced at Carl’s cycle, they added washers to the clutch cover bolts to balance the clutch as well as drilled holes in the fixed halve.
 

ZRP Engineering

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Comparison

Let me know any questions you guys have. We designed this cover to be stronger as our top priority. The towers and spyder in this clutch are not as stiff as they should be so we are trying to help them the best we can.
The stock curved shape is the strongest vs a circle or straight line from tower to tower, we have the analysis to prove that. Also in our experience, these style of billet clutch covers need to be 7075. 6061 does not hold up. We scrapped and warrantied $40,000 in covers back in 2014 learning that lesson so unfortunately we know from experience.
Our second priority was reduced rotation inertia, i.e. takes less energy to spin, which we were able to do by 11% vs stock. This is what you feel in throttle response vs how much lighter it is in grams.

Our cover provides .050 more clearance to the spyder nut. We split the difference vs stock to try to limit this interaction occurring but did not go all the way as we did not want the primary to over shift vs the secondary.
 

ullose272

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Let me know any questions you guys have. We designed this cover to be stronger as our top priority. The towers and spyder in this clutch are not as stiff as they should be so we are trying to help them the best we can.
The stock curved shape is the strongest vs a circle or straight line from tower to tower, we have the analysis to prove that. Also in our experience, these style of billet clutch covers need to be 7075. 6061 does not hold up. We scrapped and warrantied $40,000 in covers back in 2014 learning that lesson so unfortunately we know from experience.
Our second priority was reduced rotation inertia, i.e. takes less energy to spin, which we were able to do by 11% vs stock. This is what you feel in throttle response vs how much lighter it is in grams.

Our cover provides .050 more clearance to the spyder nut. We split the difference vs stock to try to limit this interaction occurring but did not go all the way as we did not want the primary to over shift vs the secondary.
Thoughts on balancing?

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Let me know any questions you guys have. We designed this cover to be stronger as our top priority. The towers and spyder in this clutch are not as stiff as they should be so we are trying to help them the best we can.
The stock curved shape is the strongest vs a circle or straight line from tower to tower, we have the analysis to prove that. Also in our experience, these style of billet clutch covers need to be 7075. 6061 does not hold up. We scrapped and warrantied $40,000 in covers back in 2014 learning that lesson so unfortunately we know from experience.
Our second priority was reduced rotation inertia, i.e. takes less energy to spin, which we were able to do by 11% vs stock. This is what you feel in throttle response vs how much lighter it is in grams.

Our cover provides .050 more clearance to the spyder nut. We split the difference vs stock to try to limit this interaction occurring but did not go all the way as we did not want the primary to over shift vs the secondary.
Speaking of sprung weight reduction of the clutch have you got any experience with removing the big weight ring on the primary?
 

ZRP Engineering

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By "where" do you mean what shops are doing it? Or where on the clutch?
We leave that up to the balance shops. They know what they are doing and can easily handle an aftermarket cover. If they cannot or use gimmicks like washers under the bolts, find a better balance shop.
 
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