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I don't recall saying what I wanted to do?? I love the way these ways drive around (very low rpms so we can hear each other talk while riding), I just want to get rid of the snap into engagement. I guess my next question is how I should modify these to alleviate that problem... like, how much of that "hump should I grind down"? Maybe just blend the roller resting position into the profile about midway down or so?
I had a guy bring me an ATV that was experiencing the very behavior you're describing. I installed a washer under the clutch retaining bolt that closed the belt gap up by about 1/16". This fixed it. You can purchase special adjustable pieces that do the same thing.
 

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Discussion Starter · #22 ·
I had a guy bring me an ATV that was experiencing the very behavior you're describing. I installed a washer under the clutch retaining bolt that closed the belt gap up by about 1/16". This fixed it. You can purchase special adjustable pieces that do the same thing.
Yeah, I'd rather just grind the hump oout of the weights since it doesn't act this way with the stock setup.
 

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Discussion Starter · #23 ·
I don't think that "hump" is big enough to make much difference. Not knowing how the rest of the clutch looks, (geometry), i.e what angle it sits at and where on the ramp the roller is at idle it's hard to give much advise.
I attached a pic of how it hangs from the pin, if that's what you mean? The roller is behind the hump at idle... right near the beginning of ramp.
 

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Side clearance is the same with both weights, since there is a gap between them and the rollers. About 0.030"
Okay.
Next question: Do these weights swing right out to touch the rollers as soon as engine is started? If so, then then it shouldn't be a big problem. If not, then the location of the COM on the diesel weights may be more toward the outside. That may be contributing to the harsh engagement. The smoothing of that flat area may not help much as you apparently found earlier.
 

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Discussion Starter · #27 ·
Okay.
Next question: Do these weights swing right out to touch the rollers as soon as engine is started? If so, then then it shouldn't be a big problem. If not, then the location of the COM on the diesel weights may be more toward the outside. That may be contributing to the harsh engagement. The smoothing of that flat area may not help much as you apparently found earlier.
They undoubtedly do. I only know this because with the softer stock spring installed, the sheave immediately shifts over and grabs the belt on a cold startup idle. Making it impossible to select gears. It will eventually snap back into the disengaged position when the engine warms up and the RPMs fall a couple hundred.

With the stiffer diesel spring, it does not grab the belt at an idle. And it's the same weights, so they will of course also be up against the rollers. And that spring is the one where it engages so hard we're scared it might break something in the drivetrain over time.

If I take the belt off and monitor movement of the primary, it behaves in exactly the same snapping manner when increasing/decreasing RPMs with each spring installed. Just at slightly different RPMs, of course. Which leads me to believe it's solely the weights that are causing this. (the stock weights move the sheave into and out of engagement as smooth as butter)
 

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Since your goal appears to be a gearing issue, would it be better to keep the stock clutching and change the gear ratio in the chain case?
 

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They undoubtedly do. I only know this because with the softer stock spring installed, the sheave immediately shifts over and grabs the belt on a cold startup idle. Making it impossible to select gears. It will eventually snap back into the disengaged position when the engine warms up and the RPMs fall a couple hundred.

With the stiffer diesel spring, it does not grab the belt at an idle. And it's the same weights, so they will of course also be up against the rollers. And that spring is the one where it engages so hard we're scared it might break something in the drivetrain over time.

If I take the belt off and monitor movement of the primary, it behaves in exactly the same snapping manner when increasing/decreasing RPMs with each spring installed. Just at slightly different RPMs, of course. Which leads me to believe it's solely the weights that are causing this. (the stock weights move the sheave into and out of engagement as smooth as butter)
This clears some things up. If that flat spot transition is located at the point of where the belt engages, then it probably is causing the harsh engagement.

I build turbocharged 2-stroke snowmobiles. I've done lots of experimentation with notched/flattened weights in an effort to delay upshifting until the turbo has a chance to build boost under light load.
 

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Discussion Starter · #30 ·
Since your goal appears to be a gearing issue, would it be better to keep the stock clutching and change the gear ratio in the chain case?
My goal isn't so much a gearing issue. It is an RPM issue. I'm fine with the gearing of the machine.
 

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Have you looked into spring options? Possible using a higher final and same engagement lb’s you might achieve a lower “wanted” rpm.
Not knowing what year,model etc kind of puts me and possibly others at a complete loss for the most part. Their are a few companies out there with jd kits for certain models. Epi is one and might be worth a call if you feel the time is warranted
 

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Discussion Starter · #33 ·
This clears some things up. If that flat spot transition is located at the point of where the belt engages, then it probably is causing the harsh engagement.

I build turbocharged 2-stroke snowmobiles. I've done lots of experimentation with notched/flattened weights in an effort to delay upshifting until the turbo has a chance to build boost under light load.
Yeah, it's the point I've been trying to get across to everyone... I guess I'm not doing a good job of it. haha
 

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The spring affects the engagement rpm a lot more than at top end. The weights have the biggest effect there.
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A higher finish means higher RPM up high, though, right? I would need to use a lower rate at both ends to lower my RPMs through the entire range.
Trying to throw what a person can with little to no info on the machine.
Your looking for a actual person that’s done the same thing for your perfect results.
I’m out. Good luck to you
 

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Discussion Starter · #37 ·
mark32786 said:
Trying to throw what a person can with little to no info on the machine.
Your looking for a actual person that’s done the same thing for your perfect results.
I’m out. Good luck to you
No, not really. A notched weight is a notched weight. Probably doesn't vary per machine
 

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No, not really. A notched weight is a notched weight. Probably doesn't vary per machine
Yes,yes it does actually but I’m getting trying to help you like others have will lead to no where.
Plenty of good advice for a person to try and reach a goal in past post. You seem to have a question looking for help but seem to be to knowledgeable to try/take it
Reason I’m asking for said model is some of those engines are used across a line of different manufacturers machines. A bobcat x machine could be the same set up as your jd. no way to know though, and not really helpful when trying to help someone. Your asking what oil should I use but don’t want to tell the machine your using. Ie no really way to help you solve your question.
 

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Discussion Starter · #39 ·
Yes,yes it does actually but I’m getting trying to help you like others have will lead to no where.
Plenty of good advice for a person to try and reach a goal in past post. You seem to have a question looking for help but seem to be to knowledgeable to try/take it
Reason I’m asking for said model is some of those engines are used across a line of different manufacturers machines. A bobcat x machine could be the same set up as your jd. no way to know though, and not really helpful when trying to help someone. Your asking what oil should I use but don’t want to tell the machine your using. Ie no really way to help you solve your question.
Sorry, didn't see anyone ask for which machine I have. It's an XUV 825i
 
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