Clutch slippage

Under heavy throttle i have experienced what i think is clutch slippage around 6 or 7 thousand rpm. It feels like i have pulled the cluth in about halfway, the motor revs higher then "catches" again and continues accelerating.

What could cause this? Bad clutch?

it is on my 78 kz1000 A2

had the same problem on my gpz750 but at about 8k to 10k replaced my springs with the red ones from parts unlimited. no problems since then. try springs first i was fully prepared to throw in a clutch pack when my mech took a look and said all was good.

If not already done, would first adjust required slack in the clutch push rod.

Am presuming there's already a little slack in the clutch cable at the handlebar end when the lever is not being squeezed.

Maladjustment in either of the above could prevent the clutch from fully engaging and thereby cause it to slip (especially under heavy load).

Good luck with the repairs.

Post edited by: Patton, at: 2007/08/27 12:13

Change your clutch cable first. It may be frayed inside the housing causing the clutch not to release properly.....chris3

I have a new cable so i will check the rod. beyond that, i will try the springs.

If i was to put in a whole new clutch, what parts are involved in that?

How many miles on the bike?

Maybe you need to try a different oil. Additives can cause the clutch to slip.

You also might be able to scuff up the plates to clean off any glaze that might be on them.

48,000 miles, I currently am running 10w40 w/ 1 quart of lucas oil to help with oil consumption.

suggestions?

1. Quit using the Lucas.

2. Do an oil and filter change to get it out of the transmission before it glazes the plates.

3. Do another oil change in 500 miles.

All of the old Kaws I've messed with had weak factory clutch springs. I think it was a warrenty gag. A clutch was easier/cheaper for a dealer to replace under warrenty than a transmition and some slippage would keep people from tearing stuff up. On all of my 650s, I replaced the factory springs with 900 inner valve springs. Works great!

I had the same problem with my GPz750 ('82). I stopped using synthetic oil, went back to the standard 10W-40 oil (changing every 2 or 3K miles) and haven't had a problem with the clutch since. At some point, I will replace the clutch plate and springs, but not yet!

So the Lucas oil additive is too slippery and may cause failure of the clutch?

Is there some other additive that would help with slight oil consumption or am i wasting my money?

You have a 30 year-old, 48k mile motor, which is air cooled.

About like mine.

Lucas may be fine for motors alone, but because it is a friction reducer, is probably not a really good additive where a clutch friction discs are concerned.

Oil consumption, what to do. . .

Replace the valve stem seals. They are probably worthless as far as oil control if they are original.

Rering the motor. The compression rings are probably ok, but the oil rings are pretty anemic as far as tension, even when new.

Sometimes knurling the piston skirts can help a bit with oil control.

Use 15w-40.

Or maybe a 20w-50.