New Member With A Clutch Problem

I joined the group since I recently bought a KZ1000J engined bike. Clutch doesn't engage well. While it is possible to shift, when the bike is stopped in gear there is clearly allot of drag and it shifts hard. To save everyone some time let me assure everyone that the problem has nothing to do with adjusting the actuation mechanism. The bike has a hydraulic actuation setup in place of the cable.

I pulled everything apart today and found the following problems
- friction plates are worn beyond the service limit
- steel plates are scored
- push rod is somewhat bent and binding
- 4 heavy duty and one shorter regular duty spring were used in the pack
- the pressure plate has some stress fractures on the outside around the bearing boss
- the clutch basket (clutch collar wear?) has runout around the output shaft

What I'd like to know is the following:
- how long is the push rod supposed to be?
- how much if any movement perpendicular to the rotation of clutch is acceptable in the clutch basket when the clutch hub is installed?
- is any amount of stress fractures on the outside of the pressure plate acceptable (most of the used pressure plates on eBay appear to have stress fractures)
- what brand friction and steel plates and springs are recommended as replacements (engine is a Gatlin Racing built MTC 1260 which dyno'ed around 140)

Thanks in advance for any and all responses.

I would suggest getting a service manual. It should have your answers.

Good Luck

Welcome to KZR
Manual YES
Try looking at APEs KZzone for clutch parts.

Dont need super race clutch
Recommend extra plate clutch and then buy new factory steels ( kit comes only with one.)
They sell new pushrods and get the needle bearing Pusher too.
use stock springs to start with to see if clutch will handle your big block
Let us know how it goes
Dave.

Pushrod length may depend on the particular hydraulic setup you have. Some require a shortened rod.

TexasKZ wrote: Pushrod length may depend on the particular hydraulic setup you have. Some require a shortened rod.

If using APE pusher and clutch they will give you a spec for rod length to be ground off stock length

Dave

Thanks for the responses folks. Factory manual arrived today. It provided zero answers to any of my questions. No specification for clutch push rod length, no specification for clutch basket shaft play.

The suggestion for looking at APE was a good one. Got a pile of GSXR engine parts fresh from their machine shop waiting to be put together this winter. Always think of them more as machine shop than a parts purveyor. The clutch plate kit looks interesting. The clutch push rod bearing setup doesn't apply to KZ1000J engines. These engines already have a full bearing in the pressure plate from the factory.

The point about the push rod length possibly not being stock given hydraulic actuation (PMFR) was one of the reasons I was asking about the stock push rod length. The referral to APE caused me to also look at Z1 Enterprises to see what they had to offer and lo and behold they sell clutch pushrods and list the dimensions. Mine measures 1.6mm short. Given the way it looks, I expect it was a stock length rod to begin with.

Normally I wouldn't ask such stupid questions but normally I'd expect a worn clutch to slip, not refuse to disengage. The basket and hub look good. The metal plates are pretty toasted and probably pretty well warped so this is my leading theory on what is causing the clutch to fail to disengage, but given everything else I'm noticing I thought I'd ask to see what help the forum might provide.

I would be very concerned about that hydraulic set up. Does it have the piston travel necessary for your KZ's clutch to disengage? If not, that would explain all the problems and the damage you have found on inspection. The piston would have to travel at least as far as the stock helix clutch pusher.

4 strong and one weak spring on a pentagon pattern - that is another source problem, for sure. I've heard of every second spring being stronger / weaker in an even numbered pattern (Like my Hondas and the late GPz1100 that uses 6 springs), but with the "star" pattern of these bikes, I would keep all the springs the same!

Kray-Z wrote: I would be very concerned about that hydraulic set up. Does it have the piston travel necessary for your KZ's clutch to disengage? If not, that would explain all the problems and the damage you have found on inspection. The piston would have to travel at least as far as the stock helix clutch pusher.

4 strong and one weak spring on a pentagon pattern - that is another source problem, for sure. I've heard of every second spring being stronger / weaker in an even numbered pattern (Like my Hondas and the late GPz1100 that uses 6 springs), but with the "star" pattern of these bikes, I would keep all the springs the same!

My first "fix" was bleed the hydraulics and lube the push rod After this didn't fix the problem, I took everything apart. Measured the throw of the slave and got 0.1". Unfortunately there is no spec for the throw of the stock pusher. I haven't been able to identify the slave, but I believe it is a Kawasaki Nissin unit which was used on the ZX7 through ZX11. Got a couple of ZX7s, so I'll probably pull the slave on one of them and measure the throw. The clutch springs are definitely a problem and could be causing the clutch to fail to disengage from uneven pressure distribution on the plates.

The plan is to buy new friction, steels, springs and pushrod. Assemble things dry and verify that the plates release. Have to see how things look with some new parts.