z750L: Repair starter clutch

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z750L: Repair starter clutch

08 Jun 2025 09:40
#913495
Hi,

I have discussed the issue with Wookie58 in another thread, but I want to start a new one since it no longer has anything to do with the electrical.
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The issue is that the starter clutch are not engages an make bad metal sound... I tried to removed the spark plug and than was it able to rotate the engine without any bad sound....

I need to start prepare the job....

My first question is about the special tools I need. From what I understand, the only special tool required is a bearing puller?
Do you have a link to one so I can see how it looks like?

I will go over the part diagram to see what gaskets I needs... but what about other parts like the starter clutch it self?




 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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Re: z750L: Repair starter clutch

08 Jun 2025 11:02
#913498
How much do you love your bike?  Ha ha.  Sorry, loaded question.

Reason for asking, is that there are a lot of possible upgrades you can do to the bike at the same time you have the engine apart.  Replacing the clutch hub rubber dampers, replacing the cush hub rubber dampers on the secondary shaft, replacing the starter clutch gear, and bearings on the secondary shaft.  And then there are guys that install a ZR7 sprag starter clutch.

Regarding tools, as you mentioned, a puller to remove the gear.  That's the only thing I can remember.

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Re: z750L: Repair starter clutch

08 Jun 2025 11:07
#913499
Heh good question :)

I’m not planning to split the crankcase, understand I repeare the starter clutch with motor installed in frame and only opening up the transmisdion cover left side and the oil pan?

Do you have link to example off a puller I need to  get the gear out?
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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Re: z750L: Repair starter clutch

08 Jun 2025 11:19
#913500
I would suggest you read the relevant section in the FSM so you are fully familiar with what is required and the job itself. There is a tool number for the puller but I'm sure you can find a cheaper alternative than the factory tool

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Re: z750L: Repair starter clutch

08 Jun 2025 11:23
#913501
Will do!

These is the manual I have used before:

 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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Re: z750L: Repair starter clutch

08 Jun 2025 11:25
#913502
There is a pdf in the file base that shows/explains how to do this task.

kzrider.com/filebase-alias?view=download...utch-repair&catid=77
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Re: z750L: Repair starter clutch

08 Jun 2025 11:58
#913503
Heh good question :)

I’m not planning to split the crankcase, understand I repeare the starter clutch with motor installed in frame and only opening up the transmisdion cover left side and the oil pan?

Do you have link to example off a puller I need to  get the gear out?
None of the things I mentioned requires splitting the cases, nor removing the engine from the frame.  

Sorry, don't recall what kind of puller.
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Re: z750L: Repair starter clutch

Yesterday 07:02 - Yesterday 07:02
#913529
How much do you love your bike?  Ha ha.  Sorry, loaded question.

Reason for asking, is that there are a lot of possible upgrades you can do to the bike at the same time you have the engine apart.  Replacing the clutch hub rubber dampers, replacing the cush hub rubber dampers on the secondary shaft, replacing the starter clutch gear, and bearings on the secondary shaft.  And then there are guys that install a ZR7 sprag starter clutch.

Regarding tools, as you mentioned, a puller to remove the gear.  That's the only thing I can remember.
I’ve read a bit more now, so I understand better what you’re saying — but not completely :)
If I only replace the spring and piston (see picture below), should the starter work fine?What would I gain by replacing the clutch hub rubber dampers, the cush hub rubber dampers on the secondary shaft, the starter clutch gear, and the bearings on the secondary shaft?Is there anything I really should do while I have it open?The starter sprockets look fine, but I only saw them through the hole after removing the starter motor. Is that the sprocket you can see through the hole?I need to decide on the parts soon so I can place the order :)

 


 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine
Last edit: Yesterday 07:02 by gordone.

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Re: z750L: Repair starter clutch

Yesterday 08:28
#913531
How much do you love your bike?  Ha ha.  Sorry, loaded question.

Reason for asking, is that there are a lot of possible upgrades you can do to the bike at the same time you have the engine apart.  Replacing the clutch hub rubber dampers, replacing the cush hub rubber dampers on the secondary shaft, replacing the starter clutch gear, and bearings on the secondary shaft.  And then there are guys that install a ZR7 sprag starter clutch.

Regarding tools, as you mentioned, a puller to remove the gear.  That's the only thing I can remember.
I’ve read a bit more now, so I understand better what you’re saying — but not completely :)
If I only replace the spring and piston (see picture below), should the starter work fine? Given the noises it was making the damage may be more than worn/broken springs and rollers  What would I gain by replacing the clutch hub rubber dampers, the cush hub rubber dampers on the secondary shaft, the starter clutch gear, and the bearings on the secondary shaft? Good practice to avoid repairs at a later date (preventative maintenance) You can inspect when stripped and make a decision from there if badly worn  Is there anything I really should do while I have it open?The starter sprockets look fine, The area that wears will only be visible when stripped  but I only saw them through the hole after removing the starter motor. Is that the sprocket you can see through the hole?I need to decide on the parts soon so I can place the order :) May be worth speaking to your supplier ref ordering all the parts (if in stock) and returning parts you don't use if still in original packaging ?



 

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Re: z750L: Repair starter clutch

Yesterday 08:45
#913533
Check for rotational play in your clutch hub and secondary sprocket hub.  If there is play, it's because the rubbers have shrunk.

[img
P1020564 by nessism , on Flickr

[img
P1020642_zpsnkr0phir by nessism , on Flickr
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Re: z750L: Repair starter clutch

Yesterday 11:42
#913535
Thank you all for the support!Do I understand it correctly — the best approach is to remove the starter clutch, inspect it visually, and then decide what parts to order?I need to import the parts from Southern Europe or the US, so returning them and getting a tax refund would be a hassle...I'm going on vacation in 4–5 weeks, so maybe the best plan is to take it apart now, place the order, and then rebuild the starter clutch when I return.

Hopefully, I can still get a few days of riding in at the end of the season. :)



 
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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