Model 20 Clutch Mechanism Jaming

Information relating to the Matchless G9 or AJS Model 20 500cc twin
Ramon518
Posts: 83
Joined: Tue Dec 31, 2002 12:00 am
Location: SOMERSET UK

Model 20 Clutch Mechanism Jaming

Post by Ramon518 »

First - the most likely reason for the gears not changing when the lever is depressed or raised is the fit of the spring loaded and pointed nipple that locates in dimples in the back of the selector plate.

when this becomes worn it simply does not travel far enough to slip into the appropriate depression and the gear refuses to locate, or if it locates, it will not stay in the gear selected.

I have recently rebuilt a 1955 B52 box and am speaking from actual experience.

The ball bearing that you can see under the K/S mechanism is fitted from the inner side of the inner casing.
At this stage (as you have described) it would be best to consider rebuilding the entire box - it is very primitive and quite simple.
I can advise - I have a spare box in my garage, and know where you can obtain replacements for most worn parts
I replaced every bearing and seal and gasket - it cost a little over £100 but was well worth the effort and makes riding a pleasure now


Ray Brinkman
mescal
Posts: 10
Joined: Tue May 20, 2003 1:00 am
Location: SOMERSET UK

Model 20 Clutch Mechanism Jaming

Post by mescal »

Ray you sound like just the sort of man I need advice from whilst I rebuild the box, but I am falling at the first hurdle: getting that inner cover off.

Those bearings on the K/S mechanism seem well fixed to the casing and the shaft (the one that the clutch pushrod slides through). I think this is what is stopping me from getting the casing off. Should the bearing come away with the casing? In which case does brute force get it off the shaft?

lawrence
Posts: 2453
Joined: Mon Jan 01, 2001 12:00 am
Location: NORTHAMPTONSHIRE UK

Model 20 Clutch Mechanism Jaming

Post by lawrence »

Hi Alan
Sorry I can't tell you how to get the cover off except to say that in the past when i've used brute force I have usually regretted it. removal of valve guides comes to mind [:(]

Lawrence [}:)]
mescal
Posts: 10
Joined: Tue May 20, 2003 1:00 am
Location: SOMERSET UK

Model 20 Clutch Mechanism Jaming

Post by mescal »

I think you are probably right Lawrence, Anyway things have moved on slightly and I have been adviced how to remove the cover with all the gears and shafts attached, which I have done (undoing the mainshaft from the clutch side). It was the main shaft that was stack in the inner case. I have yet to acertain why.

Thanks, Alan

Locked