Friction Zone Enhancement

webbmeister25d · 07-25-2012, 05:47 PM

It seems that there is a device manufactured for Yamaha cruisers that consists of an OEM clutch lever drilled in such a way that the geometry of the pull is changed. Two things are claimed to result: First, the pressure needed to pull the lever in is diminished by about 1/3 (good for arthritic hands etc.?) and second, the friction zone starts with the lever much closer to the handle and is somewhat wider (leading to greater comfort and better low speed control?)

There is also discussion about how this is an old moto-cross trick for getting better control of the friction zone for competitive riding. It is described as something that has been a diy-type project since "forever." I've never heard of it - but I'm new and haven't heard of much. Here's the address of the commercial product: http://www.theclevver.com. Thoughts? Helpful for a GZ (assuming a diy project using a GZ lever as the project base)?

Jim

Water Warrior 2 · 07-25-2012, 08:51 PM

The GZ really doesn't have a hard clutch pull compared to the Yamaha cruisers which are bigger and some are even likely to have a hydraulic clutch which is harder to pull from what I have read. With the GZ just make sure the lever pivot point is lubed and the cable is lubed and adjusted correctly. Old hands do take a beating in stop/go traffic but that is just part of the riding experience. Over the counter pain relievers should help a bunch. I have them in the 1st aid kit in case I get sore hands/wrist on a long journey.
A lot of soreness can be traced to too firm a grip on the bars while riding. That is one of my biggest bad habits on the Vstrom.
Getting back to the DIY idea, I don't think you can successfully modify a clutch lever.
Another thing that wil make your hands sore and tired is vibration. A set of grip puppies over the stock grips will soak up a lot of vibs. They work well and don't cost much.

alantf · 07-26-2012, 04:36 AM

Can't get my head round this. How does drilling a hole in something alter the geometry of it? Also, looking at the link, I can't see any difference in the "before" & "after" pictures of the clutch lever. Am I missing something? :??:

Water Warrior 2 · 07-26-2012, 09:33 AM

It's all about altering the geometry and machanical advantage of the lever. Aftermarket levers would be the easiest if available. Altering an OEM lever would be pretty darn frustrating if not impossible. You would have to fill in the holes for the pivot bolt and cable end so they could be redrilled in a slightly different position. Probably only 1 or 2 mm would make the difference.

webbmeister25d · 07-26-2012, 04:35 PM

Water Warrior is correct in his last post. Apparently, moving the pivot hole in the lever by a small amount causes enough of a change in geometry when the lever is pulled that the pull becomes much easier.

That is only the secondary benefit, though. The primary benefit is claimed to be that the change in geometry causes the clutch to begin to engage when the lever is closer to the handle. This apparently widens the friction zone so you have more space with which to control clutch engagement. If you look at the before and after pictures on the Clevver site, you will see that on the stock setup, the point of the start of clutch engagement occurs when the lever is roughly 20 degrees beyond parallel with the handle. With the Clevver, the point of engagement occurs when the lever is roughly parallel with the handle. In both pictures, the end of the friction zone appears to be roughly in the same place and the free play zones seem unchanged as well. Looking at the pictures and seeing the visual result of the change of geometry seems to lend credibility to the claim of a wider, more precisely controllable friction zone.

This solution was developed for a particular family of bikes from a single manufacturer. These bikes are described as having clutch levers that operate like on-off switches. The solution claims to provide more fine-grained control. It appears that the guy who makes these makes them out of OEM handles. Perhaps he is able to get them from Yamaha without the pivot holes pre-drilled. Curiosity has got the best of me - I've ordered one and will post pics when it arrives.

In the meantime, here is a link to a long thread discussing the device. http://www.yamahamotorcycleforum.com/fo ... 669&page=1 This is where I read that Moto-Cross riders have done this mod to their bikes on their own for a long time. I'm not sure if you have to sign on to read. Moderator, apologies if posting this link is inappropriate. I checked the protocol post and didn't find a prohibition. If it is inappropriate, I completely understand your deleting the link.

And my question to the community remains: Might this principle be applicable to a GZ and perhaps make an already nicely ride-able bike even more so?

**jonathan180iq** · 07-27-2012, 08:16 AM

This is pretty unnecessary for the GZ.
Can it enhance the rideability of an already nice-to-ride bike? I don't think so.
You're trying to solve a problem that doesn't exist.

If you want some new fancy levers, get some. But don't do so under the idea that it will somehow make your riding experience better. It will improve rideability about as much as new shoe strings improve the walkability of shoes.

Seriously, I can see why this would be wanted on a bike that is notoriously known for short frictions zones or ridiculous long lever pulls. But the GZ is neither.

07-25-2012, 05:47 PM	#1
webbmeister25d Member Join Date: Jul 2012 Location: Wauconda, IL Posts: 35	Friction Zone Enhancement It seems that there is a device manufactured for Yamaha cruisers that consists of an OEM clutch lever drilled in such a way that the geometry of the pull is changed. Two things are claimed to result: First, the pressure needed to pull the lever in is diminished by about 1/3 (good for arthritic hands etc.?) and second, the friction zone starts with the lever much closer to the handle and is somewhat wider (leading to greater comfort and better low speed control?) There is also discussion about how this is an old moto-cross trick for getting better control of the friction zone for competitive riding. It is described as something that has been a diy-type project since "forever." I've never heard of it - but I'm new and haven't heard of much. Here's the address of the commercial product: http://www.theclevver.com. Thoughts? Helpful for a GZ (assuming a diy project using a GZ lever as the project base)? Jim Login or Register to Remove Ads
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07-25-2012, 08:51 PM	#2
Water Warrior 2 Senior Member Join Date: Dec 2006 Location: Squamish B.C Canada Posts: 11,409	Re: Friction Zone Enhancement The GZ really doesn't have a hard clutch pull compared to the Yamaha cruisers which are bigger and some are even likely to have a hydraulic clutch which is harder to pull from what I have read. With the GZ just make sure the lever pivot point is lubed and the cable is lubed and adjusted correctly. Old hands do take a beating in stop/go traffic but that is just part of the riding experience. Over the counter pain relievers should help a bunch. I have them in the 1st aid kit in case I get sore hands/wrist on a long journey. A lot of soreness can be traced to too firm a grip on the bars while riding. That is one of my biggest bad habits on the Vstrom. Getting back to the DIY idea, I don't think you can successfully modify a clutch lever. Another thing that wil make your hands sore and tired is vibration. A set of grip puppies over the stock grips will soak up a lot of vibs. They work well and don't cost much.
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07-26-2012, 04:36 AM	#3
alantf Senior Member Join Date: Nov 2008 Location: Tenerife (Spain) Posts: 3,715	Re: Friction Zone Enhancement Can't get my head round this. How does drilling a hole in something alter the geometry of it? Also, looking at the link, I can't see any difference in the "before" & "after" pictures of the clutch lever. Am I missing something? :??: __________________ By birth an Englishman, by the grace of God a Yorkshireman. Login or Register to Remove Ads
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07-26-2012, 09:33 AM	#4
Water Warrior 2 Senior Member Join Date: Dec 2006 Location: Squamish B.C Canada Posts: 11,409	Re: Friction Zone Enhancement It's all about altering the geometry and machanical advantage of the lever. Aftermarket levers would be the easiest if available. Altering an OEM lever would be pretty darn frustrating if not impossible. You would have to fill in the holes for the pivot bolt and cable end so they could be redrilled in a slightly different position. Probably only 1 or 2 mm would make the difference.
	0

07-26-2012, 04:35 PM	#5
webbmeister25d Member Join Date: Jul 2012 Location: Wauconda, IL Posts: 35	Re: Friction Zone Enhancement Water Warrior is correct in his last post. Apparently, moving the pivot hole in the lever by a small amount causes enough of a change in geometry when the lever is pulled that the pull becomes much easier. That is only the secondary benefit, though. The primary benefit is claimed to be that the change in geometry causes the clutch to begin to engage when the lever is closer to the handle. This apparently widens the friction zone so you have more space with which to control clutch engagement. If you look at the before and after pictures on the Clevver site, you will see that on the stock setup, the point of the start of clutch engagement occurs when the lever is roughly 20 degrees beyond parallel with the handle. With the Clevver, the point of engagement occurs when the lever is roughly parallel with the handle. In both pictures, the end of the friction zone appears to be roughly in the same place and the free play zones seem unchanged as well. Looking at the pictures and seeing the visual result of the change of geometry seems to lend credibility to the claim of a wider, more precisely controllable friction zone. This solution was developed for a particular family of bikes from a single manufacturer. These bikes are described as having clutch levers that operate like on-off switches. The solution claims to provide more fine-grained control. It appears that the guy who makes these makes them out of OEM handles. Perhaps he is able to get them from Yamaha without the pivot holes pre-drilled. Curiosity has got the best of me - I've ordered one and will post pics when it arrives. In the meantime, here is a link to a long thread discussing the device. http://www.yamahamotorcycleforum.com/fo ... 669&page=1 This is where I read that Moto-Cross riders have done this mod to their bikes on their own for a long time. I'm not sure if you have to sign on to read. Moderator, apologies if posting this link is inappropriate. I checked the protocol post and didn't find a prohibition. If it is inappropriate, I completely understand your deleting the link. And my question to the community remains: Might this principle be applicable to a GZ and perhaps make an already nicely ride-able bike even more so? Login or Register to Remove Ads
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07-27-2012, 08:16 AM	#6
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	Re: Friction Zone Enhancement This is pretty unnecessary for the GZ. Can it enhance the rideability of an already nice-to-ride bike? I don't think so. You're trying to solve a problem that doesn't exist. If you want some new fancy levers, get some. But don't do so under the idea that it will somehow make your riding experience better. It will improve rideability about as much as new shoe strings improve the walkability of shoes. Seriously, I can see why this would be wanted on a bike that is notoriously known for short frictions zones or ridiculous long lever pulls. But the GZ is neither.
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