KZ1000/1100 clutch springs

The #s up there are actual measured #s. I have a spring compression gauge and did the measurements at 23.5mm that is why I indicated (as measured)

otakar wrote:

The #s up there are actual measured #s. I have a spring compression gauge and did the measurements at 23.5mm that is why I indicated (as measured)

Per FSM for '77~78 KZ1000, clutch spring tension at 23.5mm test length should measure 51.81psi~58.42psi with 47.40psi service limit (Converts to 23.5kg~26.5kg with 21.5 kg service limit). Stock springs 55PSI@ 23.5mm compression (book Spec) is within such specs.

Per FSM for '77~78 KZ1000, smaller (inner) valve spring tension at 23.6mm test length should measure 26.20~28.96kg with service limit of 24.7kg. (Converts to 57.76~63.85psi with service limit of 54.45psi).

valve spring 51PSI@ 23.5mm comp. (as measured) is for whatever reason far under FSM specs. And a valve spring tension of 57.76~63.85psi is of course not softer than a 55psi clutch spring tension.

Good Luck!

Using the innver valve spring used to be what racers used to lock up their clutches with the added HP. I did and the clutch pull was definitely harder then stock springs. Ran them for awhile and switched back to stock springs and lived with it. Poor left hand got much bigger then right hand! :laugh:

If you are right handed you must do the required exercises to build up that-one also :woohoo: The valve springs I was measuring were some high performance KZ650 valve springs at the 51psi. Stock 650/750 springs are rated at only 38psi Those are from my old road racing days when I used to install new valve springs at the beginning of each season. I did measure some other KZ1100 springs which measured at 62psi of force. Still- the clutch springs I have from my Z1R measure at 90psi. Now you know why i removed them and have them in a box. The 62 pri springs sound like they would be fine. I will first have to see what the springs measure which I ordered. They are rated at 54psi at 1". So most likely just under 60psi at the 23.5mm length.

I got the first set of clutch springs which I ordered today. They are the EBC CKS7 springs. I measured the compression force on these and it is 61psi@ 23.5mm. This is a bit lower than advertised but still a bit better than stock. I hope that I get the other set tomorrow. I would like to install the new clutch ASAP.

It will be interesting to see how the new springs stack up. Sounds like they aren't much more then stock though. If nothing else, you can run one set for awhile and then try another set to find the ones that do the job and are right for everyday use. Keep us posted. I for one would like to know what you find out on this.

I just got my second set of aftermarket clutch springs. These also measured at 60Psi@ 23.5mm. I guess that the 60# range is about standard for the aftermaket springs. I will install a set this weekend and see how they grab. They measure only about 10% stronger than stock. I hope that this will be enough.

I took my clutch apart today. I tested the springs that were in there and they were at .45psi@ 23.5mm that is way under spec. I installed the ons I had that tested at about 62psi and installed new plates. I mounted my new Gun-Koted clutch cover, and removed my alternator cover to Gun-Kote tomorrow. I think that the springs were most of my problem. i will let you guys know on Tuesday.

Looks like you had a few things going against you so far...more HP and weak springs. should notice a big difference now....just depends on how much!

Well' I didn't have much time to finish the bike today like I wanted. My water heater burst and flooded my basement. I had to take the day and start to clean it up and install a new heater. Lost a lot of stuff. Hopefully I will have time tomorrow to media blast the alternator cover so I can gun-Kote it and install it. I am anxious to try my new springs and clutch, before it gets too cold. They are saying possible snow on Turkey day.