Shakedown results - Clutch

[Jdraper]

After getting my AJS back on the road last summer after a LONG pause (nearly 30 years), I decided to use the enforced time at home to deal with a few issues that have cropped up.

Firstly Clutch:

This is not disengaging properly, leading to graunchy gear changes, especially into 1st from stationary. No adjustment seems to make it go away and without a detachable dome (I now have one, but its cosmetically rough), the primary drive cases have to be split. Operating the clutch shows that the plate was not lifting squarely - tried adjusting the springs - a little better, but in for a penny etc I decided to take the lot apart, so as to get at the final drive sprocket which I know is 16 tooth, making the bike very under-geared. First surprise was that the clutch basket was rubbing on the back chaincase. Looking at the chain, it was clear that something was mis-aligned - see picture. The chain case is lovely and flat, so something else is wrong - have I missed out a spacer somewhere? Long story short, my detective work shows that the back half case spacer is 1 and a half inches dead, instead of the 1 and 13/32 that the parts book states (010953). I am pretty sure that this is the cause of the clutch basket fouling the case. Another trip to the spares site.

Taking the clutch basket apart, I found a few other nasties. The clutch centre shows serious wear to the splines - see picture, fortunately I have a spare one which seems to be in much better shape. Also the springs seem a bit agricultural compared to the ones that came with my spare clutch basket - no chamfered spring seat - I think I will fit the ones with the chamfered ends & see what happens.

So now the wait for the new parts including a 19 tooth sprocket.

Stay Safe

Jeremy

[dave16mct]

19T gearbox sprocket is a hell of a jump from the standard 16T. What engine sprocket have you got?
Dave.

[Mick D]

not disengaging properly, leading to graunchy gear changes, especially into 1st from stationary

Hi

Do you habitually free the clutch before starting the bike? If not the plates can tend to stick together and make your first selection noisy even when the clutch is adjusted correctly.

Regards Mick

[dave16mct]

Just thought did you mean engine sprocket or gearbox? As standard it would have been engine 21T and gearbox 16T.
Dave.

[Jdraper]

Yes, always free the clutch before setting off - the problem is stopping at lights or junctions - mucho clutch drag. Tried re routing the cable, not much difference - what way is best?

Re final drive - I have a 21 tooth engine sprocket and new final sprockets are available in 17 & 19 tooth flavours. I would rather go too far over geared, as that establishes a limit than try a 17 and wonder if there was much difference. At 16 quid a pop its not much to gamble on... Engine sprockets - sheesh!

At 16 teeth, it feels a little boy racerish...

I attach pictures of the crude vs neatly chamfered clutch springs - which would you use?! Also the clutch basket which is nice and level.

Jeremy

[Andy51]

The unchamfered springs look horrible! Use the chamfered ones, and if they are 'tired' new ones can't be that expensive. I don't know what size clutch centre you have (350 is shallower than 500) but if the plates are level with the top there is a danger that the top one comes out of engagement when clutch lifted. Andy

[Jdraper]

It is the correct 5 spring unit for the 500. All plates are there but there is a thick, stepped plate at the rear of the stack - is this correct? Clutch has not come disengaged so far - quite the opposite! Both sets of springs are the same length, so I will use the chamfered ones, which I am guessing are original parts.

Jeremy

[clive]

stepped plates were used, the step of course needs to be innermost

[Jdraper]

Parts arrived in good time from Club Spares to have session at the weekend. New 19 tooth final drive sprocket fitted - final drive chain only just allowed the larger unit. New primary drive case inner spacer has lined things up better - I hadn't realised how tight things are at the clutch/final drive/cases interface.. I went back to the older clutch springs and adjusted up to spec.

I also took the opportunity to fit one of the new arrowhead primary drive sealing bands, as the old rubber ring was quite perished and leaked badly. I didn't use sealant as I may be going back in soon!

Fired it up and went for a shakedown run locally, including some hills and fast sections. First impressions are that the high gearing has made the bike more relaxed at speed - 50mph is 2800rpm, 60 around 3200rpm (according to my LCD revcounter). Getting underway is fine, and again is relaxed, without bogging down. Top gear in town 25-35 is snatchy; a bit uncomfortable, so dropping to third is required. Once underway at 35+ the drive is smooth. Power is sufficient not to need to change down for hills (at least round here). It may be different Two-up, but that's for another day. I think I will stick with the 19 tooth sprocket for a while.

Clutch is much better, but still a clunk into 1st from stationary. Another feature of the clutch which has always been there is a pronounced 'Clack' or 'Crack' at full extension. Doesn't seem to affect operation, and is only there when I fully pull the clutch on - any ideas why (B52 box)? It has always made this noise... even with no engine running.

A major revelation is that the chaincase does not leak anymore! There was one drop of oil overnight, which may have come from the gearbox (I filled to the level plug).

Oh, and I got a big shock the first time I went to use the rear brake - I forgot to re-adjust it after fitting the new sprocket and putting the wheel forward to allow enough slack in the chain.

Jeremy

[dave16mct]

The 'clack' is from the clutch lift mechanism. You can see it in the gearbox if you remove the filler cap and look down as you pull the clutch lever. Study the manual. It has 2 plates with 3 ball bearings between. 3 dimples in each plate. When the lever is pulled they ride up and push the clutch pushrod to lift the clutch. When worn they jump back causing the clacking noise. Also the size of hndlebar lever can affect it. The original levers had 7/8" centres. Pattern one often have 1 1/8" centres. This gives a heavy action and pulls the lifter too far. It can be adjusted out but not ideal. Always free the clutch by pulling in the lever and kickstarting a few times before starting. It often prevents the clunk into gear.
Dave.