AJS & Matchless Owners Club

I've just had to push the bike home.... My G3 with an AMC gearbox and clutch came to an ignominious stop about a mile from home. The clutch cable had gone completely slack (but it isn't broken) and there was an ominous rattle from the primary chain case. I suspect that the nut that retains the clutch centre onto the gearbox main shaft has come undone (I'll check it out later in the week but for now, the bike is in the garage.) From memory, there isn't a locking tab washer on this nut, just a spring washer. I know it WAS done up tight when I assembled the primary drive as I tightened it with an air impact wrench but I didn't use any Loctite... Should I have done and what's the recommended torque figure for that nut (if there is one)?
Cheers
John

EDIT.... I should add that the nut and spring washer (040373 and 040374) were both brand new parts from the AMOC Spares

Just had a look on a m c classic spares, check first could be 040374 lock washer for retaining nut. But check first I'm not up to scratch on this model. Just trying to help.

A spring washer is correct. Locktite is a perfectly suitable thing to use alongside the spring washer.

Hi

Page 50 of the workshop manual may give you some pointers - I'm not a fan of air hammers when torqueing up, OK for loosening though.

Regards Mick

Is this the nut that came off? I have never used a washer for that. Never had one come loose. It is a thin nut, perhaps the air tool was too much for it and damaged the thread?

Rob Harknett wrote:

Ashampoo_Snap_2018.06.25_22h04m09s_001_.png

Is this the nut that came off? I have never used a washer for that. Never had one come loose. It is a thin nut, perhaps the air tool was too much for it and damaged the thread?

Rob... I've not taken the primary drive cover off yet so I'm not sure. If it is just the push rod adjusting screw and nut that has come loose, that would be an easier fix (I didn't do that one up with an air wrench!) but judging by the noise that was coming from inside the chain case just before I stopped, I suspect it's the nut that holds the clutch centre hub onto the gearbox mainshaft that has come loose and the whole clutch assembly has moved outboard and was contacting the inside of the chaincase. I'll know better a little later in the week when I'll have a chance to take the cover off.

Mick D wrote:Hi

Page 50 of the workshop manual may give you some pointers - I'm not a fan of air hammers when torqueing up, OK for loosening though.

Regards Mick

Had a look at workshop manual as you suggest. That implies that a nut working loose is caused by damaged hub splines and that "over-tightening of the nut should be avoided". The hub splines were certainly OK when the clutch was assembled and the bike was being driven by the engine until I stopped it so the spines haven't sheared off (as they had a habit of doing on a G9 I had many years ago). I'll have to wait until I've got the cover off to find out what's going on.

Rob Harknett wrote:

Ashampoo_Snap_2018.06.25_22h04m09s_001_.png

Is this the nut that came off? I have never used a washer for that. Never had one come loose. It is a thin nut, perhaps the air tool was too much for it and damaged the thread?

Rob... my apologies... You were absolutely right. I had a few minutes spare this morning so I took the domed clutch cover off and the pushrod adjusting screw had unscrewed completely. It was trapped between the cover and the pressure plate. Fortunately no damage other than a bit of paint missing from the inside of the clutch cover. It's back together again and I've made sure that the locking nut is tight. Hopefully, It won't happen again.

Well done, thanks for the feedback of the end result. All too often we never hear what may had caused a problem. Many members have tried to help resolve.
Just a thought, I'll have to check that thin nuts pt. number. Those half nuts as I think they are referred to, are used as lock nuts on some girder fork spindles. They are not easy to find, I brought a pack years ago, now all used up or given to others. Using a full nut only half on looks awful, cutting down a full nut not easy with just an hacksaw and file.

From memory, the plug spanner fits that nut. If using the "box spanner with the welded on flat strip" type spanner it's easier to set this as the screwdiver fits through the box spanner part to maintain position and the box spanner clears the casing.

Johnny B