Clutch Adjustment

Hello everyone,

I have a 1983 KZ550 LTD Shaft. I'm having a problem were the clutch slips at around 7k rpm. I have adjusted the cable on both the lever end and the clutch cover side to about 3/16" play.

The shop manual I have mentions no other clutch adjustments. Do I just have to replace the clutch friction plates and springs or is there another adjustment I can do?

Thanks in advance everyone!

What oil is in the bike? Ed

I have Castrol GTX 10w40 in it atm

Zach wrote: I have Castrol GTX 10w40 in it atm

That may be contributing to your clutch slipping. I used that same oil in my KZ650 for a number of years, but without knowing it Castrol changed their formula. My clutch slipped and I ended up replacing the clutch. What I learned from that experience was that the formula for many motor oils was changed to protect automobile catalytic convertors. The only way to be absolutely sure that the oil you are using is formulated for use with wet clutches is to use oil that has "JASO-MA" on the bottle.

Here's a writeup on the subject that I did a couple years ago:

The ingredients in oils have changed over the years. For example, today's Castrol GTX oil (and pretty much all other AUTOMOBILE oil) is not the same as it was in the 1980's. Back then it worked great in KZ bikes. But, things have changed. Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engines from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers." These work fine and offer good protection for normal AUTOMOBILE engines. However, today's AUTOMOBILE oil "Friction Modifiers" are destructive to wet clutches. KZ bikes (and many other brands) have wet clutches. As a result of these oil chemistry changes a distinction needed to be made between those oils which are suitable for wet clutches and those which are not. That distinction was documented by the Japanese Engine Oil Standards Implementation Panel (JASO). JASO developed a number of different oil specifications for different applications. The specifications that apply to 4 stroke motorcycles fall under the "4T Specifications." Within the 4T specifications the JASO MA class oils are specifically formulated for 4 stroke motorcycles with wet clutches.

Using oils that are not designated as meeting the JASO-MA standard may be destructive to KZ clutches. Here's a link that may be helpful:


www.oilspecifications.org/jaso.php

Ed

Thank you! That is very helpful information. Is it as simple as an oil change to fix this problem potentially or do I need to do the plates as well as the oil?

If the clutch isn't slipping too badly you may want to see if changing the oil and riding the bike for a few hundred miles fixes the problem. In my case it did not, but mine had gotten to the point where it was slipping quite a bit. Ed

I use Castrol GTX 10W40 in all of my bikes, including an '81 KZ550 and have no clutch issues whatsoever. But I seldom get up to 7000 rpm. I had the clutch apart in one of my Z1B's a few weeks ago and measured the plates...they were all within spec, showing no signs of wear. But again...I almost never reach 7,000 rpm. It's a little easier on the 550 because it revs higher than a Z1 but that's probably about 90 mph, which is much faster than I drive.

After reading what Ed wrote I plan to check into that oil.

hardrockminer wrote: I use Castrol GTX 10W40 in all of my bikes, including an '81 KZ550 and have no clutch issues whatsoever. But I seldom get up to 7000 rpm. I had the clutch apart in one of my Z1B's a few weeks ago and measured the plates...they were all within spec, showing no signs of wear. But again...I almost never reach 7,000 rpm. It's a little easier on the 550 because it revs higher than a Z1 but that's probably about 90 mph, which is much faster than I drive.

After reading what Ed wrote I plan to check into that oil.

Ed makes a very important point on what oils work and which dont.
A lot of us suffered the same issue Ed did .
Back in the day . When our bikes were new I ran Castrol in all my motors 20/ 50 GTX . 10 / 40 depending .
They are not the oils they once were.
Lots of good new choices that wont hurt your motor or clutches.
I currently use Shell Rotella Diesel oil. Cheap Great oil and readily available
Dave

Same here.
Steve

Thank you all, I will definitely look into the oil and check my plates and springs. Other than that and the cable adjustments, is there anything else I should know about? I know some of the earlier models had clutch adjustment screws on the sprocket side. I don't believe mine has that (and obviously doesn't have a sprocket), but is there any adjustment like that I need to put a wrench on?

It should have an adjustment in the left cover under a small cover with two screws.
Steve

If you check the service manual it will tell you how to adjust the clutch correctly, including the adjustment behind the "sprocket" cover.