Clutch mod

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jdeitz1979

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So, I was tipped to a mod for the vmax clutch. Haven’t tried it yet, but this post will hopefully sort out the pros vs cons and opinions of the mod.

When installing the Barnett pressure plate and new friction discs if you’re installing those as well, you can remove the clutch boss ring, clutch plate, 1/2 friction disc, plate n seat. Once those are removed you add a full clutch plate and friction disc in place of removed 1/2 plate.

If anyone has this, or knows about it, has done it or can share any information on this would be greatly appreciated


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The arrangement that you are proposing to change is there to reduce clutch noise with the clutch pulled in and smooth the gear changes.

Therefore if you do this you will notice a little more noise (rattle) from the clutch when the clutch is disengaged and the gears will engage with more of a clonk.

The only benefit would be if you are getting clutch slip; your friction discs are nearing the end of their useful life and you can only afford to buy one replacement or you have or are going to increase the power output of your bike.
 
If you do a bit of searching, the 1/2-disc friction plate is to act as a type of ease-of-engagement on downshifts.

PCW in Schenectady NY has sold for years a kit for replacement of this. OEM Yamaha friction discs of the correct number of plates, and a gasket. I have this mod in my '92.
 
If you do a bit of searching, the 1/2-disc friction plate is to act as a type of ease-of-engagement on downshifts.

PCW in Schenectady NY has sold for years a kit for replacement of this. OEM Yamaha friction discs of the correct number of plates, and a gasket. I have this mod in my '92.



Thanks for the info FM. I was also told about milling down the spring posts .100” to give a stiffer spring on the pressure plate. Do you have that in yours as well?

Since you have this done to your clutch, how does it feel compared to the stock set up? I was told that this mod is a pretty good one, and that the guys that have it like it.


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PCW sells a heavy-duty diaphragm spring, easier on your hand than the double-disc diaphragm spring. I haven't done any milling of the screw towers. I like my clutch as it does not prove hard to pull repeatedly. It holds well.
 
PCW sells a heavy-duty diaphragm spring, easier on your hand than the double-disc diaphragm spring. I haven't done any milling of the screw towers. I like my clutch as it does not prove hard to pull repeatedly. It holds well.



Do you have more clutch noise? Or gear clonk?


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if you're referring to a full disk replacement in the back? Nothing noticeable the few times I've done it. It's a fairly common upgrade.



Yes I am, and it’s one I’m considering. Just wanted a little info and opinions.


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I suggest the PCW extra friction disc, heavy-duty diaphragm spring, and rough-up your 'steelies.' Assuming your friction discs are due for replacement, and you're replacing them, you should get good use out of your clutch. PCW gives you a new clutch cover gasket too. Be sure to ask for all of that. Call them, their website is probably not going to work for your ordering.
 
I suggest the PCW extra friction disc, heavy-duty diaphragm spring, and rough-up your 'steelies.' Assuming your friction discs are due for replacement, and you're replacing them, you should get good use out of your clutch. PCW gives you a new clutch cover gasket too. Be sure to ask for all of that. Call them, their website is probably not going to work for your ordering.



My Steelies are in very good shape. Out of three clutches I took the best of them all and are in the bike. I have the Barnett friction discs and pressure plate in at the moment and will be keeping it.
I rode out to lcr on the bike a few nights back after working out the bugs n leaks after putting in the used donor for my bike.
Had Lary give the look over on it and just hung out there for a few hours before heading home. We got talking about some mods and such and that’s when the clutch mods came up. I wanted to get info from people that have the mod or something close to it for more information.
I did check pcw out, and probably will get something from them, but not at the moment.


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I will vouch for the PCW diaphragm spring and the install of a full friction plate.
I did that to my bike many years ago and love it. I also have the 'bearing' mod in my adjustable clutch handle and the clutch is smooth and not at all hard to pull.

With this mod, I have never had any clutch slip no matter what synthetic oil I've tried. And if I pull in the clutch in 5th gear, while riding and let the engine idle down, I can abruptly let go of the clutch handle and hear a 'chirp' from the rear tire (again, in 5th gear. I know that any bike will chirp the tire in a lower gear...) as it grabs that nicely.

I heard that the 1/2 friction disk thing was designed as a sort of 'slipper' clutch when downshifting. Sport bikes have those setups so you don't skid the rear tire when downshifting hard. But the way they did it on the Vmax can cause clutch slip when applying power and using some synthetic oils.

I don't have any strange noises when idling or revving with the clutch lever pulled in and would never return this setup to stock again. I like my long lasting, non-slipping clutch setup. Great for burnouts also as there's simply no slipping going on that may otherwise eventually burn up the clutch.

Vinnie
 
I will vouch for the PCW diaphragm spring and the install of a full friction plate.
I did that to my bike many years ago and love it. I also have the 'bearing' mod in my adjustable clutch handle and the clutch is smooth and not at all hard to pull.

With this mod, I have never had any clutch slip no matter what synthetic oil I've tried. And if I pull in the clutch in 5th gear, while riding and let the engine idle down, I can abruptly let go of the clutch handle and hear a 'chirp' from the rear tire (again, in 5th gear. I know that any bike will chirp the tire in a lower gear...) as it grabs that nicely.

I heard that the 1/2 friction disk thing was designed as a sort of 'slipper' clutch when downshifting. Sport bikes have those setups so you don't skid the rear tire when downshifting hard. But the way they did it on the Vmax can cause clutch slip when applying power and using some synthetic oils.

I don't have any strange noises when idling or revving with the clutch lever pulled in and would never return this setup to stock again. I like my long lasting, non-slipping clutch setup. Great for burnouts also as there's simply no slipping going on that may otherwise eventually burn up the clutch.

Vinnie



Thanks for the information. I’m curious to know what the bearing mod you talk of is


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I would not suggest to mill down the inner basket posts! There are a ton of options for stronger holding power from the Barnett (with many spring options) to the HD PCW version (we also sell) and the DD version. Or, you can get a lockup clutch and there is even an auto clutch conversion.

We've been doing the half disc elimination for 30+ years along with the DD clutch mod (second spring).
 
The clutch lever mod is this: to make the pull easier by boring out the levers mounting hole and inserting a small roller bearing (friction fit) that will ride on the bolt that secures the lever to the perch. I have a procedure but it is at home on the backup drive, I'll try to remember to post it when I get home.
 

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