Kz750 starter clutch repair failure

Hi everyone,
I recently replaced my starter clutch with a starter clutch kit.
It seemed to do the trick, but after starting many times the slipping clutch problem has returned. I'm starting to wonder if the shaft is worn? Or the clutch housing was the problem. Any insight into this would be very welcome.

Did you replace the gear? Ed650 has a nice picture on here showing the flat spots that are beat on it after many years of usage. I replaced it and the housing along with the pins, rollers and springs ..... I really drug my feet doing it and finally got the motor back in this last fall and am ready to fire it up as soon as the weather breaks. I'm praying all the cash and work was well spent and mine lasts and works correctly.

Here's that picture. The used one will slip. Ed

My starter clutch gear looked like Ed's "used" gear and it works fine. In fact, every starter clutch I've ever seen look like that. I get that wear on that surface can be bad if it goes beyond some point, just understand that some marks on the gear doesn't necessarily mean the gear is bad though.

The "used" gear surface is normal and it will works fine
if the roller housing is out of spec (worn out ramp) you have no proper functioning.
The starter clutch is a combination of direction of rotation, traction, friction and form closure.

Firstly, thank you for all the replies.

I noted that the difference in diameter between the new and old rollers was tiny. I suppose bigger rollers, new gear, may not even solve the problem - depending if the ramps on the housing are worn.

I'll have to take it out and inspect. Where can I get "new" parts?

thanks again for the insights, you guys rock!

I'm not sure, but you may still be able to order the starter clutch assembly from a local or online dealer. The part number for the assembly is 13193-1062. See:


If not, the site below says they have one in stock. Ed

www.z-power.co.uk/merchantmanager/produc...php?products_id=1068

I got the rollers, springs and pins at Partzilla and the housing at Cheap Cycle parts...... it comes with rollers springs and pins so I have a extra set but sorry I plan on keeping them....... the gear was a pain to find and was directed to Z power too and got it there. It was quite a bit more though due to the currency diff, shipping and higher retail.

Since (4 years ago now) (damn!) (avaliability might have changed now) I've seen the gear at Ebay but are far and in between. Ebay had a cheaper I believe to be probably from China housing that someone on here was thinking about but can't remember if they try'd it or who it was.. Don't really like that idea though..... Z1 has helped on things before but no luck with these parts. (except the rollers and springs). I also got the roller bearing for the gear to tighten things up, and a new clutch hub nut and locking washer and thrust washer for that too.

Wanted to add when I was searching for this I found that more than a few just replaced the rollers and springs and after a year it went bad again so thats why I decided to do the whole assembly.

Hello, I read your topic and I have a question.

The starter clutch of my Kz750 is damaged. The only way how to fix the problem is to make a new starter clutch gear. In order to do so I need to find out the accurate diameter of the part which runs on 3 rollers in the clutch assy. According to my information, the diameter must be very precise.

Can anyone help? Thank you.

I attach a photo

krojci wrote: Hello, I read your topic and I have a question.

The starter clutch of my Kz750 is damaged. The only way how to fix the problem is to make a new starter clutch gear. In order to do so I need to find out the accurate diameter of the part which runs on 3 rollers in the clutch assy. According to my information, the diameter must be very precise.

Can anyone help? Thank you.

I attach a photo

It's available from Bike Bandit it appears.

www.bikebandit.com/oem-parts/detail/kawa...?m=150535&sch=425106

Shabba wrote:

krojci wrote:
It's available from Bike Bandit it appears.

www.bikebandit.com/oem-parts/detail/kawa...?m=150535&sch=425106

Unfortunately, he needs the part for a 1978 KZ750-B3 twin rather than a 4-cylinder KZ750, so that part won't fit his bike. He could help everyone help him if he would add his bike's year and model (1978 KZ750-B3) to his signature line.

It would save a lot of energy if there was someway to force members to to that. Ed

Hi Everyone,

Apologies for not posting a result to this thread earlier.
I was able to purchase a whole second hand clutch from a second hand parts dealer, The donor bike had lower mileage than mine.
Admittedly this was a gamble as I really had now idea what the state the part would have been in .

I then removed the "old" starter clutch from my bike, and compared the two.
As mentioned in my original post, I had replaced the springs pins and rollers in this clutch but that didn't do the trick.
After careful inspection, the teeth on the sprocket "new" second hand part looked worse than that of my original clutch, so I tossed that and kept the original sprocket, The ramps were definitely badly worn on the "old" clutch housing, so I simply used the new pins etc, and the "new" clutch housing.

She hasn't missed a start since.
Admittedly this was a gamble, but the cost of buying a new part especially if you include shipping to South Africa didn't really make sense to me.

Just from my experience I wouldn't take the diameter of the hub of the sprocket as a real indicator of wear.. sure it probably plays a part, but from what I saw (and I am sorry I didn't take photos of the work housing) the ramps were a clear indicator of the wear.