AJS & Matchless Owners Club

Have been reading up here on shimming camshafts, so armed with a selection of shims and new oil seal for the inlet cam started yesterday what seemed to be a straightforward job.

Confused at the first fence. So, unscrewed the a/r centre bolt which does seem overlong at nearly two inches, then realised there is a larger diameter thread in the first half inch or so of the shaft so obviously, (eventually!!) realised the screw just taken out was not going to help in popping off the a/r unit as it simply screwed into the shaft.

Luckily found a screw that fitted the larger thread then was able to insert a plain spacing rod which when the screw was nipped up on it and tapped lightly, did the job as we expect it to.

Remainder of the excercise went smoothly, but it was a bit of a mystery with the two different thread diameters, as I've seen no mention of it anywhere.

Anyone seen this before?

Cheers,

Steve

I wonder what bike and mag you have.

Top of page 31 of the 1957 to 1966 Singles workshop manual for mag ign.

http://archives.jampot.dk/book/Workshop ... .NEILL.pdf

For coil ignition see bottom of page 31.

The ar unit should have a dished washer which locates on the two pins to the side of the bolt and a u washer which slides under the bolt head. Turn the bolt one way it tightens up the ar unit, turn it the other way and it acts as an extractor breaking the seal to the magneto shaft. Assuming this is a SR1 mag and not the later coil ignition.
Edit ignore this as I see from your profile your bike is a 1960 model. Helps to mention year when asking for advice, unless you're smart like Spriddler who probably checked before answering 😛

clive wrote:The ar unit should have a dished washer which locates on the two pins to the side of the bolt and a u washer which slides under the bolt head. Turn the bolt one way it tightens up the ar unit, turn it the other way and it acts as an extractor breaking the seal to the magneto shaft. Assuming this is a SR1 mag and not the later coil ignition.
Edit ignore this as I see from your profile your bike is a 1960 model. Helps to mention year when asking for advice, unless you're smart like Spriddler who probably checked before answering 😛

I did look to see bikes owned, but that may not mean that is the bike the question refers to.
So you must state what year / model with question. Only then can you be assured you are getting info you want. Even then you may have wrong parts fitted, like wrong engine, wrong mag. Also people have not wasted there time searching wrong info for you.

Not an expert on the difference according to years etc.But, if its got an SR1 mag then be careful when removing the timing cover. When removing the cover the blind bushing for the i/l cam will tend to pull the cam out ( due to hydraulic suction of the oil )thus disturbing the timing. The trick is to lift the cover away just enough to slid a knife blade btn the cover and the cam to keep it in place.

Thanks all for the speedy replies and apologies for not identifying my bike clearly. It sometimes escapes my attention that there are many versions of the veritable G3, so I'll do better next time.

Embarrassed that I had read the manual many times and searched the topic but still managed to not appreciate that a different sized extraction bolt would be needed.

Still, luckily I found one and the job progressed. One thing though, I did notice that the bushes in the cover were below the surface of the aluminum so could not have any effect on controlling end float.

Had they been assembled incorrectly in the past?

I could fall foul of the yearsbut I think that the Neill red book says on an engine rebuild, adjust by actually moving the bushes but maybe that wasn't the camshaft. I've shimmed mine before though as I'm wary of shifting something too much and then it gets slack and..........................................

Johnny B

Johnny,
Think it's possible to move the outer camshaft bushes on my 1960 G3 with a bit of extra work but as you say, would have to be done very carefully to get right.

My question was the fact that the outer bushes are set below the surface of the cover, so have no effect on controlling end float of the cam shafts. Therefore the shims run in between the cam gear face and the outer cover casting!

Anyway, I've shimmed mine and the horrible clacking sound has gone so that does it for me.

Regards,

Steve