Like all motorcycles with electric start the z650 has a starter clutch and like all things mechanical, its prone to failure. The most common failures range from broken springs and damaged rollers to cracked assemblies. And in a similar vein to the Gpz900R starter clutch its right in the middle of the engine!
Unlike the GPz900R which I documented here, the z650 starter clutch is relatively easy to remove even with the engine in frame. I’ve found that you only need to remove the clutch cover and sump to gain access and remove the starter clutch, in the process you will need to have on hand some gaskets and possibly some replacement countersunk screws if the process has been done before by a less skilled person.
Basic tools are required to perform this task, a socket set, some spanners, impact driver and 6mm Hex Drive key
- Starter Clutch Repair Kit (as a minimum, 3 springs as the pins and rollers are usually OK).
- Sump gasket
- Clutch Cover Gasket
- Oil Filter
- Engine Oil
- If damaged – M6x50 Countersunk set screw (Qty 2)
The process is pretty straight forward, I drained the sump and removed the oil filter, took out the battery and removed the tank and side covers. We need to do this so we can safely tip over the bike (engine and all) to access the sump easier.
As a bonus, you can do a filter and oil change aftrwards if you need too, otherwise tipping over the bike to its side means the oil drops down one side and not out the sump.
First remove the foot brake, and right hand foot peg, this makes it easier to get the clutch cover off. Remove the kick starter if you still have one.
Remove the cover set screws, there are 2 long ones at 80mm and the rest are 30mm in length. You should now see the clutch basket, while we have access to it, check it for play.
Remove the 5 set screws that hold the clutch basket together, loosen each in turn and then keep repeating so the pressure is evenly removed. Clean them and measure the springs, lay them on a clean surface, remove the pressure plate and clutch plates.The z650 has 7 fibre plates and 6 steel plates, the manual says the service range is 3.7mm to 3.9mm, mine are 3.8mm
After the plates are removed, pull out the Spring Plate Pusher, that’s what the push rod pushes against, behind it is a ball bearing which needs to come out.
An easy way to get the ball bearing out is either use a magnetic screw driver or just gently push on the clutch rod from the other side, that implies removing the cover or quickly snapping the clutch in and out.
To remove the clutch housing, I used an air impact driver and socket, it took about 20-30 seconds for it to spin loose. After removing the Clutch Housing, I spotted bits of crap, most likely from the cush drive rubbers sealed inside, as the plates look fine.
Once you remove the Clutch Housing you should be able to gain access to the oil pump screws, two of which double as bearing retainer screws.To remove these use an impact driver with the correct sized bit, these ones will need replacing as the heads are damaged. There is also one under the gasket at the base of the Secondary Shaft Gear.
After removal of the screws, you need to remove the oil pump set screw, its 10mm but make sure you are holding the oil pump so it doesn’t drop out!Looking inside the sump with the pump now coming out you can see the starter clutch.You should be able to lift the Secondary Shaft up once the retainer is pulled back, in this picture the circlip on the gear has been removed, however you don’t actually need to do this, leave it on.Lift the shaft up and while its coming out, you can remove the starter clutch gear
First remove the Starter Clutch Gear:Now you can see the starter clutch clearly, unlink it from the Hi-Vo chainAnd remove it as a unit.This is the issue, the spring that pushes against the roller (via a pin) is broken, so the roller won’t engage the Starter Gear shaft.
Removing the three high tensile set screws allows access to the rollers, bottom left is the broken spring, pins are good and the rollers are in perfect shape:
The gear assemble on the bench for checking, no cracks or damage. Not bad for a 41 years old bike!
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- z650B1 – Reassembly
- z650B1 – Wiring
- z650B1 – Repairs and Final Finishing
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- Tutorials & Info
- z650 Cafe Racer Build