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Discussion Starter · #1 ·
Started last season during my trip up to VT, and when I got my sled started a week or so ago it was still an issue. (Not that I thought sitting in a dusty barn for the Summer would magically cure the issue...)

My sled will get to about 7200-7500 rpm and it falls flat on its face. It pulls very strong in the low and mid-range, but it won't get over that final hump. On my previous trip to Tug Hill, it was pulling hard and 80+ on long straights wasn't uncommon. No issues.

I watched the clutches last week, and it seemed that the primary wasn't engaging fully. Would that limit revs?

I haven't checked compression yet, but I did a fresh top end only 500 miles ago, and have been breaking it in correctly. I'm thinking that's not the culprit.

I plan on tearing the clutches apart and reclutching for this season. I have seen Almond/Blue w/ 64g for the primary, and a silver/blue for the secondary. Are there any special tools I need to do this or can I tear them apart pretty easily without?


Any and all ideas appreciated. Will get a compression tester next week at some point and hopefully cancel out that possibility.
 

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Make sure the clutches are clean, dirty clutches can cause lots of problems.
 

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No real special tools needed, snap ring pliers and maybe an extra set of hands at times, but I would have to check my setup, but stock pipe, 64g weights, HSP yellow primary(lower engagement) HSP 50-36s helix and HSP orange secondary spring. Make sure your clutches are cleaned, the belt is adjusted correctly, and the weights are moving freely.
 

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Discussion Starter · #4 ·
Seems simple enough. I think I can find someone with a clutch puller and I'll get it worked out.

I'm guessing I should probably replace the buttons and stuff while I'm in the secondary as well.


This is a rookie question - what difference do the weights make? I see stock weights are 60g and you're suggesting 64g. What advantage does that give me over stock?
 

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The heavier weights will lower the engagement RPM. Less centrifugal force needed to compress the stock spring. But if you get a heavier spring, you need heavier weights to maintain the engadgement speed because it takes more force to compress a heavier spring. and vice-versa, lighter weights raise the engadgement speed and lighter springs will lower it.
 

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The difference in engagement rpms for me was hardly noticeable, what I went heavier for was top end rpms, I was overrevving so I went heavier, I could go just a tad heavier now even but I will wait on that.
 

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MasterSkitelz said:
The heavier weights will lower the engagement RPM. Less centrifugal force needed to compress the stock spring. But if you get a heavier spring, you need heavier weights to maintain the engadgement speed because it takes more force to compress a heavier spring. and vice-versa, lighter weights raise the engadgement speed and lighter springs will lower it.
SO would this be a good combo? 1988 indy trail 488 fan.
primary - red/w, 10-54's...secondary - red 36 deg. #2 location
 

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Discussion Starter · #8 ·
dtmmil said:
The difference in engagement rpms for me was hardly noticeable, what I went heavier for was top end rpms, I was overrevving so I went heavier, I could go just a tad heavier now even but I will wait on that.
What top-end RPM am I looking at for the sweet spot?

Jeez, I feel like I've never owned a sled before asking these questions... [confused]


I need to find my shop manual..... [baldy]
 

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KingPrat said:
dtmmil said:
The difference in engagement rpms for me was hardly noticeable, what I went heavier for was top end rpms, I was overrevving so I went heavier, I could go just a tad heavier now even but I will wait on that.
What top-end RPM am I looking at for the sweet spot?

Jeez, I feel like I've never owned a sled before asking these questions... [confused]


I need to find my shop manual..... [baldy]
I think it's 8000 - 8600.
 

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8000 rpms is what I have been told by several, including pockets on HCS.
 

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Discussion Starter · #12 ·
MuscleD said:
How old is your belt?
Belt was new at the beginning of last season.



dtmmil said:
8000 rpms is what I have been told by several, including pockets on HCS.
OK, hopefully that's all I need to know for now. Once I get the parts and the clutches off I'll probably be back.

Thanks guys.
 

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71rdrnr said:
MasterSkitelz said:
The heavier weights will lower the engagement RPM. Less centrifugal force needed to compress the stock spring. But if you get a heavier spring, you need heavier weights to maintain the engadgement speed because it takes more force to compress a heavier spring. and vice-versa, lighter weights raise the engadgement speed and lighter springs will lower it.
SO would this be a good combo? 1988 indy trail 488 fan.
primary - red/w, 10-54's...secondary - red 36 deg. #2 location

I don't know what a good set-up would be, I just know how the clutches work.
 

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Discussion Starter · #14 ·
New question: How do I identify what helix is in there? I can't find a PN anywhere.

It honestly looks like a stock helix, but would like to be 100% sure. Only identification I can see is a stamp inside that reads "T1"

Any help is appreciated.
 

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well i have mine apart on the bench right now, and the stock is an R-11 (atleast i have been told that on the rmks), and mine is stamped R11 and also has a 36 not sure what that is about
 

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7800-8000 rpm
any black spots on the primary clutch?
make sure motor mounts are broken.

i personally would remove primary clutch, inspect primary spring to make sure its not broken. and make sure movable sheave can move freely.

inspect buttons and helix in secondary clutch.
 

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T1 is your helix, there is a chart that tells the specs, same with your R-11, that is a 48-36 I believe, could be wrong, I have the chart somewhere I will see if I can find it.
 
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