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Let me preface this post with a little background, I will be as brief as possible to still get the point across.
I ordered a machined sheave kit from JBS last spring. I had problems after the initial installation with hitting the rev limiter from a dead stop if I mashed the go pedal, and also topping out at 48-50mph. James from JBS gave me progressively heavier sliding weights until the issue went away. The unfortunate problem was, he didn't, and still doesn't believe I should be using that heavy of a weight(18g), and said I have a bad fuel map. He is wrong, and won't admit it. My machine was professionally tuned by HMF Racing in Cleveland, Ohio. You know, one of the biggest names in aftermarket exhaust? There have been a lot of exchanges between James and I, but the end result is that he has proven to me he is not a businessman, he is a bully, and a child, and refuses to admit he is wrong. So, I ordered a Hunterworks Sheave Kit and installed it yesterday. If you want more details, PM me. That is not what the thread is supposed to cover.

Now, on to the meat and potatoes.

The existing setup consisted of the following:

Stock Secondary Spring w/plastic Anti-Friction washers
JBS Extreme Sheave
18g DR. Pulley OverDrive Sliding Weights
Yamaha Factory Stock Belt
Yamaha Factory Greases
No Shims

The new setup:
Gold Secondary Spring w/ "Slippery Washers"
Hunterworks Sheave
18g Greaseless Roller Weights
Yamaha Factory Stock Belt
.5mm Shim

My machine has 28"x10"x12" ITP Blackwater Evolutions on all 4 corners. I also have a full HMF exhaust from the head back, tuned with their Optimizer piggy back fuel controller made by Dobeck. I recently added a windshield and rear window, and a lift kit, which made a noticeable difference in attainable top speed. With the JBS setup, my top speed on flat ground with the only added weight being me, 205lbs, was 53mph. Previously, before the windshield, I was able to hit 55-56, but it took FOREVER to get there. With the windshield on, and the Hunterworks sheave, I was able to hit 55-56 AND hit the rev limiter, which means there is more power on the table if I were to raise the rev limiter.

I calculated the Primary to Secondary sheave ratio for both setups. The JBS setup was at exactly 2.79 to 1. The Hunterworks was 2.89 to 1. This was calculated based on actual physical movement, and measuring that movement. So the HW sheave has approximately a 3.5% lower starting gear ration than the JBS. Not significant, but still lower.

I measured the height which the belt rode up out of the Secondary Sheave with both as well. JBS was 2.9mm, HW was 3.8mm. This was measured with a set of dial calipers. The height difference confirms the lower gear ratio with the HW sheave.

I only had time to do a basic acceleration and top speed test with each sheave, but I will update this thread when I have more set time in the HW sheave, and compare it to my previous experience with the JBS sheave.

IMG_20160312_120225938.jpg IMG_20160312_142643803.jpg
 

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It seems to me a well thought out discussion on personal experiences with either/or with NO MUDSLINGING in either direction should be welcomed in any public forum.
 

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There have been a lot of exchanges between James and I, but the end result is that he has proven to me he is not a businessman, he is a bully, and a child, and refuses to admit he is wrong.
I'll be brief here. This is a common statement from many VS forum members. I am not going to discuss this here, but a few facts about sheaves.

Let me preface this post with a little background, I will be as brief as possible to still get the point across.
I ordered a machined sheave kit from JBS last spring. I had problems after the initial installation with hitting the rev limiter from a dead stop if I mashed the go pedal, and also topping out at 48-50mph. James from JBS gave me progressively heavier sliding weights until the issue went away. The unfortunate problem was, he didn't, and still doesn't believe I should be using that heavy of a weight(18g), and said I have a bad fuel map. He is wrong, and won't admit it. My machine was professionally tuned by HMF Racing in Cleveland, Ohio. You know, one of the biggest names in aftermarket exhaust? There have been a lot of exchanges between James and I, but the end result is that he has proven to me he is not a businessman, he is a bully, and a child, and refuses to admit he is wrong. So, I ordered a Hunterworks Sheave Kit and installed it yesterday. If you want more details, PM me. That is not what the thread is supposed to cover.
I own both Hunterworks and JBS clutches. I also understand the engineering behind both designs. I currently run my own "Tinken" brand clutch which is a radically advanced version of the Hunterworks clutch with a low ratio of 4:1 and a belt exposure of 6.6mm. (JBS was 2.9mm, HW was 3.8mm, more is better here).



Clutch tuning is an art and it isn't everyone's cup of tea. Everyone seems to think they are the master of it, but in my +33 years of clutch tuning experience, very few actually know what they are doing. Many tuners are confused about which component of the clutch should be used for what kind of tune you are trying to achieve.

First off, there are many more factors to look at here. Many people believe that the secondary spring controls your engine rpm during low end power delivery and in an attempt to provide more power off the bottom, continue to add larger and stronger springs. It does control this to a point, but that's not what it is there for. Engine rpm is controlled by a ratio of weight vs. spring pressure. The spring size is determined by the amount of torque your engine develops, too light of spring and you will slip your belt, too strong of spring and you will never reach your maximum speed potential while you chew up belts from over pinching. The correct setup will have a secondary spring with just the right amount of belt tension as to not slip the belt, then the weight of the rollers can be adjusted in order to achieve the correct ratio to produce maximum torque through engine rpm. This may very well of been one of the problems with FordTruckMan's cvt.

Another problem is what us engineers in the plastic industry call "Slip Stick". This refers to the ability of the sliding roller to move from a resting point. Even though some plastics are self lubricating, they also tend to stick in a resting position until enough force is applied to get them moving. Over drive weights (originally invented by Hunterworks, now abandoned and used in JBS sheaves), suffer from this problem. Combined with the large surface area at the top, OD weights tend to require large amounts of force to begin sliding. The problem which arises is that once there is enough centrifugal force applied to the OD weight to begin moving, the weights tend to slingshot to the outer edge of the clutch. This may produce a great acceleration effect, but will not yield a smooth performing clutch on technical trails and over obstacles. Round roller weights have very little surface area exposed to the clutch surfaces producing very smooth and controlled clutch performance.



Also, the overdrive weight is confined to one position, therefore will continue to wear and create an even larger high friction surface area. Here again the round roller is superior due to the fact that it is not limited to one position. The round roller will "Roll" to another area to slide from and some sliding rolls will actually roll while power is applied to the clutch (seen in the image below, there are no slide flats on that roller). When rolling, friction is reduced by the power of 10, producing even higher efficiency. Over drive weights sometimes roll on deceleration and at that point the clutch will no longer function correctly. The entire clutch must be disassembled in order to correct the weight positions. Round rollers never suffer from this issue and are still the most reliable form of weights.



To combat the friction and slip stick issues associated with OD weights, many installers choose to add a lightweight grease. Note that grease was originally added by Yamaha in order to quiet the all metal round rollers, not as a lubricant. There are issues with grease as it loves to collect dust and debris. It is a real mess when servicing the clutch as seen in the image below.



In addition, you must use a sealed clutch cover to keep the grease from oozing out from centrifugal force. This limits the outer sheaves through before the screws come in contact with the spider support cage. Greaseless systems have no mess, no outer cover and more room to move back and forth. Sure, you can purchase a slightly longer spider cage, but we are talking about millimeters here and without the grease cover, even more room to move into low gear position. No grease round roller weights means easy cleanup, no slip stick smooth clutch action, reliability and longer lasting. I wash out my sheaves with a garden hose, no hassle.



Centrifugal weights come in all kinds of shapes and sizes. For the Wolverine, the standard round roller weight is 30mm in height. The overdrive weight is 32mm in height. This means that when the weight is in its resting position, the sheave will be opened up 2mm further with the roller weight producing the lower take off ratio. When the weights are in their outer positions, the OD weights will push the sheave in 2mm further than the roller weights, theoretically producing higher top speeds. To date, there are no sheaves which contain re-machined valley ways in order to combat the 2mm taller over drive weight. For this reason, the OD weight is plagued with the inability to obtain the low end of what is possible with the round roller. In order to increase the top speed of a sheave with round weights, the outer half of the sheaves are machined in order to provide a slightly longer roller track for round rollers to achieve the ending height of OD weights.




The Hunterworks sheave; grease free, fully machined and friction coated. Respectfully named the "Best" because it is.


As an engineer, I like products which work reliably and hassle free. Therefore I stand behind the Hunterworks clutch and products. Hunterworks customer service is top notch and their prices are some of the lowest in this industry. :cool:
 

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I will say one thing, I do not see a double standard at all.

The issue I have seen is, the no one has been able to come up with any technical comparison that is in JBS's favor without calling me an idiot, don't field test, use a marker etc

As the other half of this I welcome a technical discussion just leave the name calling out stick to the subject at hand

Also I find it very interesting that the biggest mouth against me has never had one of my sheaves on anything just name calls and that is why he gets time outs or whatever he calls it and I have nothing to do it with it. As a matter of fact, I recently read where he didn't even have a JBS one and said he could not wait to get one. So how do you stand on the stump all the time talking about someone or their product comparing it to another and don't have either.

I don't say much on here anymore, reason why is sheaves sell so fast I can't keep them in stock, this forum or any forum does not help nor hurt the sales of them. What sells them is word of mouth.

I also find it interesting that a guy comes on here tells a very technical explanation and accurate I might add comparison and people who have never tried ours jump on him and then just say this is one sided it is not.

So please someone give some technical comparison for the JBS sheave and leave the ugly and name calling out.

I also find it extremely interesting that anyone that actual has one of our sheaves never says anything bad about it.

Our sheaves changed about 6 months ago before that, in a area or two we needed to make a change we did, that is why I jokingly call it it the best now, it is.

The worst part is, someone on the other side just making things up saying our sheaves does, the latest and the absolutely most ridiculous is we don't cut a groove in the sheave where the seal goes after we machine it and it will let grease come out or the seal will come out. Guess what? neither have ever happened. Come on, I am not stupid, I know how people get on forums and say negative things, don't you think if that is the case I would just change it?



Todd
 

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Something I may not of made clear in my post above was that because of the slip-stick friction of OD weights, more weight is required if this weight style is used. This throws the ratio balance off and the highest performance available can never be achieved. Either too much spring is used causing top speed loss or too little spring is used causing belt slippage. This has nothing to do with high or low ratios, but the smooth power delivery as the weights travel along the sheave ramps.

Round weights also have some slip stick, but because the surface area which makes contact is similar to the top of a sphere, the contact is minimal and friction is reduced. Upon weight roll, the friction is further reduced changing from kinetic friction to rolling friction which is 10 times less. Less friction equals more precise power transfer.

So here is a quick comparison. The first image is OD weights after 700 miles greaseless. This resulted in a failure as the weights were crushed out of round and had a severely flat spotted bottom. They were done.






Here are Velocity weights at 1500 miles of testing in an open cvt. I drove them across the desert and up the mountains, sometimes in 120 degree heat, in mud, snow and submerged under water. Like my C12 belt, they don't even care. Self lubricating, they are amazing, and still running. My sheave will be long worn out before the weights. Hit them with the pressure washer, ready to go again.



Velocity Weights, thick, self lubricating, slip stick free. These never require greasing and will outlast all other weights which use plastic slip on covers.

 

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Thanks FordTruckMan, this is a post I've been asking to see for a long time and its very knowledgeable and helpful. I'm still up in the air on sheaves, If I want one, if I need one, who to buy off of and how it all works for me and my type of riding.
 

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I like your explanation.

Mine would be too simple, I created OD weights years ago and abandoned them and went back to round cause I thought they was better.

Your explanation is why but I am not smart enough to explain it like that!!! LOL

Todd
 

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Thanks FordTruckMan, this is a post I've been asking to see for a long time and its very knowledgeable and helpful. I'm still up in the air on sheaves, If I want one, if I need one, who to buy off of and how it all works for me and my type of riding.
I agree with you, Yamaha did a pretty good job on the wolverine sheave and cut the top side out for us aftermarket people, they in a sense gave us a machined sheave already and also why we sell probably 3 to 1 rhino sheaves over wolverine

What you gain is take off, the coating and greaseless and tad bit more top speed

If that is a plus for you then do it, if not then leave it stock but I would do the wet clutch slug kit to make it last much longer.

Todd
 

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Max, I don't see anyone saying anything about JBS negative at all, I see someone pointing out some technical differences

If you anyone wants to do that then please do

So Hunterworks gets a fair shake on the hotrod forum? Do you want any of us to believe that?

I have had multiple customers call, email etc about saying anything good our us on that forum and get blasted.

Max, you know that is true so if you don't like what goes on here, don't come. Pretty simple, I don't go there.

And there is a positive write up on this forum about a JBS sheave and it stays on here, no one removed it.

Here is you a link to the positive one

http://www.wolverineforums.com/foru...new-sheave-28-blackwater-evo-s-installed.html

Todd
 

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I've seen plenty positive about JBS here. The only times I've seen it shut down was when things started getting personal or when someone else starts talking smack on a thread that doesn't have anything to do with JBS.
 

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I don't know nothing about sheaves but I do know my son gets on here and he don't need to be reading language like that, if you cannot be no cleaner I urge the moderaters to ban you.
I agree and that is why Max and I have came to an agreement that he should be out riding rather than visiting our forums. Sorry for the interruption. :)
 

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I calculated the Primary to Secondary sheave ration for both setups. The JBS setup was at exactly 2.79 to 1. The Hunterworks was 2.89 to 1. This was calculated based on actual physical movement, and measuring that movement. So the HW sheave has approximately a 3.5% lower starting gear ration than the JBS. Not significant, but still lower.

I measured the height which the belt rode up out of the Secondary Sheave with both as well. JBS was 2.9mm, HW was 3.8mm. This was measured with a set of dial calipers. The height difference confirms the lower gear ratio with the HW sheave.

I only had time to do a basic acceleration and top speed test with each sheave, but I will update this thread when I have more set time in the HW sheave, and compare it to my previous experience with the JBS sheave.

View attachment 13361 View attachment 13369
I found a good reference video on the Stock sheave ratio -> 2.5:1. The Hunterworks clutch is 2.9:1 and is a pretty good jump over stock, even closer to the Rhino clutch than I previously expected. :cool:

 

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Tinken- I have read many of your sheave mod articles across multiple different forums. Is it possible to modify my sheave further for even more power and still keep my cvt covers on? Can you explain some disadvantages of doing so as well?
-Thanks
 

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It's possible to add shims to your primary sheave which will lower your starting gear ratio, but the belt rising out of your secondary may hit your cvt cover. I suppose you could grind a little material away from the inside of your cvt cover around the outside of your secondary with a flap wheel. I am not sure how much you have to file off, although, it could be done. You will loose some top speed from the modification because your sheave will no longer be able to squeeze together the amount you have now separated the clutch. I'm not sure that is a real issue with the Wolverine because for one, it's not that much you are loosing and two, I think it lacks the power needed to achieve maximum geared speed anyway. Personally, I would rather have as low of a geared clutch as possible, especially when running larger diameter tires.

I would check with Hunterworks before making any modifications. The "Shim Mod" link is located in my signature below, along with other mods.


Here are examples of what the secondary belt will look like with various shimming. Here with no shims:



Here is with some shims:






Here is with maximum shims: That's about 3.1mm.

It's a really inexpensive mod, but it will take a little bit of Tinkering with to get the most out of it. Your belt moves lower in the primary and higher in your secondary clutch, therefor yielding lower take off torque. But you have to be careful how much you expose your belt out of your secondary sheave so that it doesn't rub against your cvt debris covers.
 
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