AJS & Matchless Owners Club

Hello

I'm finishing off my basketcase rebuild and have a problem when fitting the dynamo sprocket to the dynamo shaft. I have to fit three thick washers behind the dynamo nut (000611) so I can fit the lock ring (000708) to the nut. If I only fit one washer the nut is too far inside the sprocket to get either the lock washer or the lock ring on. However, if I use three washers I can get it on but the nut is only engaging a few threads.

Im not sure where the nut came from, but it looks right and is 13mm long. The sprocket came with the basketcase but also looks correct. Either the nut is too short or the sprocket recess is too deep (mine is 13mm deep and the sprocket is 23mm end to end).

Can anyone confirm the correct dimensions for me?

Thanks

Brian

Post a picture of the nut and associated bits just to ensure what you have is correct.

"FWIW I have two identical dynamo sprockets lying around here, with keyway. Deep 10.5 mm, total 21 mm. I "do" only AJS/M, so maybe your sprocket is from another British bike.
A picture of nut + washer + spring can be found in this this thread.

Albert

Thanks to those who have replied to my post. The accurate measurement of the sprocket is 23.42mm overall width, 13.5mm deep (where the nut goes) and 55mm diameter from end of tooth to end of tooth. The nut is 12.7mm. I have attached an image of the nut and clip (and the three washers I am having to use) and also images for when only one washer is used and also when three are used (and clip then fits)..

Brian

Does the chain line up fine with the engine sprocket? If so, nice one.

I have this exact issue with my basket case. My lock washer from stock is flat without bent tangs.

Looking at the jampot spares picture of the dynamo sprocket the counterbore is wider, perhaps to allow the lock washer to fit inside rather than on top as you have shown.

I was literally tomorrow going to pop it in a lathe and open out the counter bore to the lock washer diameter, only 3/32 deep to allow it to fit in.

With the extra plain washers I would worry there is not enough thread engagement.

Regards

Adam

The picture at JSL shows a counter bore diameter about 22 mm. That's what I also measure in my sprockets.
There must be many members who can confirm or reject my previous data. The nasty thing is that normally you can't even look at the sprocket as it is hidden in the primary chain case.

Albert

I don't have a sprocket to measure but the normal fixing is one washer and with the nut proud so the lock washer, with tabs bent, fits outside. I don't agree about the illustration in the spares section of the sprocket. Looks normal to me and the illustration of the lock washer shows tabs bent.

The tabs on the pattern lock washers are not bent, you have to do that bit yourself...................even more work, its a hard life made harder.

Apologies for the mis-information on the lock washer, I am not familiar with the single so it's a steep learning curve.

However I have taken a 3/32 cut into my non standard sprocket to allow me to utilise the lock washer. There could be the other option on just making a custom longer nut to get over this particular issue. Being careful on the clearance between the nut and the primary chain.