Clutch Replacement

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Posts: 27
Joined: Mon Nov 24, 2014 9:37 pm
Location: ESSEX UK

Clutch Replacement

Postby onthebuses » Sat Sep 21, 2019 9:03 am

HI Im just about to put a new clutch in my 1950 G80 its the cp variant with 5 friction plates and 5 springs just need a bit of advice cheers
1) should the new plates be soaked in oil beforehand ?
2) what is the correct procedure for tightening the springs up?
3) what oil for the primary case?
4)what oil for the Engine
Thanks in advance Gary

User avatar
Posts: 3835
Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: Clutch Replacement

Postby clive » Sat Sep 21, 2019 9:46 am

2)Take off the clutch rod adjuster cap on the CP gearbox to ensure you have free play on the rod. Ensure all your springs are the same length, replace if significant variation. screw down the clutch spring nuts until the heads are flush with spring cups. make sure there is lots of free play at the clutch lever. put adjuster cap back on, does the end clutch plate move as you tighten up the two screws for the adjuster cap? IF there is just the hint of a movement then turn the nut a half turn to give free play. Remember you need to screw the nut outto move the rod in and vice versa. So once you have the plate just showing movement you need to turn the rod adjuster nut a half turn in to give the free play. Then adjust the clutch cable for about 1/8" free movement. Now set up a pointer so that you can see if the clutch plate is pulling away equally. Use the kickstart to turn the gearbox with the clutch pulled out. The plate should not wobble if it does use small amounts of adjustment on the spring nuts. The more brutal amongst us then start the engine, put the front wheel against a wall and with the front brake on into first gear and with about quarter revs see if we can stall the engine as we let the clutch out. If we can it probably means you wont get clutch slip once you have reassembled everything and spent hours (unsuccesfully) trying to seal the primary chaincase.
3) I use old engine oil. I prefer this method of disposing of it, ie spreading it round the country wherever I park, to pouring it down the nearest drain.
4) If you search the forum for "oil" you will find 17993 entries on the forum on this subject. Everyone will be different! I use SAE 50 as I no longer ride both summer and winter.
if it ain't broke don't fix

User avatar
Posts: 652
Joined: Wed Mar 05, 2014 4:21 pm
Location: Oxted, Surrey

Re: Clutch Replacement

Postby Peter Morris » Sat Sep 21, 2019 10:17 am

clive wrote:
3) I use old engine oil. I prefer this method of disposing of it, ie spreading it round the country wherever I park, to pouring it down the nearest drain.


Posts: 6679
Joined: Wed Sep 01, 2004 12:00 am

Re: Clutch Replacement

Postby SPRIDDLER » Sat Sep 21, 2019 11:54 am

If you are not yet aware, all the info is in the Owners and the Workshop manuals in the archives, under the 'Books' heading which you can find here:

For example, here's a link from within those archives (under 'Books') to just one of many technical manuals for your bike. Clutch assembly/adjustment is detailed with illustrations on pages 119 and 120: ... chless.pdf

This particular manual opens sideways on, so if you are using Windows (and want to avoid getting a crick in your neck) right click on the document and choose 'Rotate clockwise' from the drop-down menu. Repeat if necessary to bring the document into correct orientation.
I poke badgers with spoons.

Return to G80 / Model 18

Who is online

Users browsing this forum: No registered users and 19 guests