81 KZ750 Clutch materials for upgrade from stock

I am ready to replace my clutch it is slipping under load. I want to upgrade from stock a notch. What brand or material should I look for and should I replace the steels also and springs? I am looking for some input to make a decision. Any comments will be helpful.

You can't beat NOS plates .......... even most of the big hp big cc bikes stick with em with a few going with the extra plate Ape set up. (Not needed in your case). Personally I like using the HD Barnett springs..... some will say they make the lever too hard to pull but I've never had a problem in the least and never had the nos plates sticking while using them....... Barnett plates where a different story though........... Its only a 10% increase in pressure and I just feel better using them. At the very lease I'd replace the stokers with new ones as they are getting up there in age and fairly cheap insurance.

The steels are probably ok to re use unless they are warped and dis colored from slipping but from what I've read that's rarely the case. Sure you know but in case not Be sure your using a Jaso rated motor cycle oil that can cause problems with slipping.

Short answer - I would not recommend doing it. The stock springs and clutch disks are more than enough for stock or somewhat modified engines. I have read of many folks who put in heavier springs, etc. and then find the clutch is very unfriendly. Personally, I had a competition clutch in my previous bike (I bought the factory prepared BSA engine from Gary Nixon) and the clutch was a serious problem for street use. One thing that happens is the clutch will bind up after sitting for a few hours and you must rock the bike back and forth MANY times with the clutch lever pulled in to free up the clutch plates. Otherwise you can actually break the engine case (guess how I know).

Instead of installing a heavier duty clutch I suggest you first try to figure out why your clutch is slipping. For example - what oil has been used in the engine? If it is not JASO-MA compliant there's a really good chance the KZ clutch will slip and need to be replaced (again, guess how I know) because the anti-friction chemistry in many automobile oils is murder on wet clutches. Does the bike have extremely high miles most of which are stop and go driving or drag racing? Has the clutch been properly adjusted during the life of the bike and is it properly adjusted now?

Seriously, if the stock clutch is slipping after being properly adjusted there may be an issue that will also affect the new clutch even if it is heavier duty than the stock clutch, so finding the cause of the slipping clutch should be the first thing you do. Ed

The Bike has it s OG clutch with 42K miles on it I had a tire that was ready for replacing so I did some power brake burnouts just for fun and to speed up me replacing the tire and well it beat up on my clutch and now with the new tire and recent drive train replaced 17 sprocket on the front and 32 on the rear new oring chain for me to have the bike back as it used to be and to enjoy all the other improvements I made. I have to get the slipping clutch done since it has been slipping and due to the issues I had getting the front sprocket nut off I need to also change the the main shaft seal (I used a smoke wrench) SO I have been leaking oil. I can fix that but I have been topping off with just motor oil. I will change back to 100% JASO-MA oil

What material I may just need to understand the difference between cork and kevlar that seems to be the options the brands are Versha Barnett and I think KG If I can understand the qualities I can make a decision I think but so far I feel that the Barnet springs are a good choice for me never had any issues with my clutch cable/handle being too hard if anything I feel it is too soft.

Maybe go over to the kz750 turbo website and read up there......... most sure like the nos plates or a lock up. Way over kill for a stock 750 or even a lightly modded one but might help you decide. Hoping some of the big time engine builders on here chime in like Larry C and Les or some of you big balled turbo guys........ And also since you've been adding reg oil like Ed said maybe just a oil change and adjust could get you were you need to be.

Thank you for the info I want to more if just changing the oil will do the trick it sounds from the other post that I need to flush it out get new clutches and start fresh

Stock everything, from experience, a totally stock set up will handle anything you can throw at it except maybe nitrous or turbo. Stock springs easier on you and the clutch cable.

Les Holt

Agree with stock.

The biggest fault with the stock setup is the springs will lose tension after 40 years. Most slipping clutches can be fixed with nothing more than new OEM springs. All bets are off though since you were doing burnouts. If the springs were weak and you abused the clutch too much then the steel plates may be damaged now too.

BTW, a new clutch cable, freshly lubed, and lubing the release device is a thing of beauty and well worth doing.

Stock.
Steve

I went looking for a video hoping to find a good explanation of the adjustment in the sprocket cover, this guy does an excellent job of explaining it! This gives a good idea how to adjust but still, you have to recognize what it is you're trying to achieve.




Les

I'm not suggesting you do this but it gives you a good idea how it works.
Steve
kzrider.com/forum/2-engine/601798-clutch-actuator-mod