Re-fixing Dynamo AJS 16MS

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PaulCh
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Re-fixing Dynamo AJS 16MS

Post by PaulCh »

When I removed the dynamo on my AJS 16MS (1957) to be re-furbished, I had difficulty removing the sprocket because there was a rubber "doughnut" surrounding the shaft between the dynamo body and the rear of the chain case. After finally getting it off I found it had a split in it so could have been pulled off. I can find no reference to this "doughnut" in the spares list or the manual. Am I right in thinking this is someone's private modification? It seems to make lining up the dynamo sprocket difficult or impossible. If I leave it off will this cause an oil leak? It is of course the tin chain case. Sorry to be asking the obvious but I am still on the learning curve.
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Rob Harknett
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Re: Re-fixing Dynamo

Post by Rob Harknett »

There is not meant to be a seal there. Just leave what was there off.
PaulCh
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Re: Re-fixing Dynamo

Post by PaulCh »

Rob Harknett wrote:There is not meant to be a seal there. Just leave what was there off.
Many thanks Rob; I was pretty certain but it is nice to have someone to confirm.
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Re: Re-fixing Dynamo AJS 16MS

Post by SPRIDDLER »

TIP
When you have refitted the dynamo and checked that the dynamo sprocket is perfectly in line with the engine sprocket make a mark on the dynamo body so that if (when) you next have to adjust the dynamo chain tension you can maintain the chain's correct alignment without having to remove the outer chaincase. If the dynamo and primary chain come into contact it will almost certainly cause serious damage to the dynamo and/or the chaincase.
Originally there was an alignment bracket bolted to the top of the dynamo body but they are often missing in later life.
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Re: Re-fixing Dynamo AJS 16MS

Post by 56G80S »

In another thread (search dynamo locating strip) it says:

"club spares they also have a dynamo locating strip complete with two screws 010962" I made my own as they weren't available at the time, thanks to Don Madden providing the dimensions.

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Re: Re-fixing Dynamo AJS 16MS

Post by Group Leader »

The locating strip can be seen here on the side of the body, if it's missing and you are going to replace it you will of course have to position the dynamo manually so that you can fix the strip in the correct position.

If it already has the strip on then you'd do well to check the alignment anyway and then, when you are sure the sprockets are perfectly in line, you'd do well to check it again just to be sure!

As Spriddler says it will get very messy if the two chains meet!

Alan
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1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
PaulCh
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Re: Re-fixing Dynamo AJS 16MS

Post by PaulCh »

SPRIDDLER wrote:TIP
When you have refitted the dynamo and checked that the dynamo sprocket is perfectly in line with the engine sprocket make a mark on the dynamo body so that if (when) you next have to adjust the dynamo chain tension you can maintain the chain's correct alignment without having to remove the outer chain case. If the dynamo and primary chain come into contact it will almost certainly cause serious damage to the dynamo and/or the chain case.
Originally there was an alignment bracket bolted to the top of the dynamo body but they are often missing in later life.
My dynamo has got the alignment bracket but of course it was removed when the dynamo was sent away. I lined up the dynamo sprocket using a pair of calipers and checking the distance between the clutch and dynamo sprockets was the same as between the two crankshaft sprockets (about 10.7mm), then re-attached the bracket. Looking a Alans photo it seems his bracket is mounted the other way round from mine where the stepped end was at the sprocket end; I don't know what difference it makes.

Many thanks everybody for the help and tips.
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Re: Re-fixing Dynamo AJS 16MS

Post by Group Leader »

PaulCh wrote:
SPRIDDLER wrote:TIP
Looking a Alans photo it seems his bracket is mounted the other way round from mine where the stepped end was at the sprocket end; I don't know what difference it makes.
I think the stepped end is to clear the slightly proud end cover if the bracket is moved to the extent of it's travel in that direction (that's the logic I applied when I put it back on :D ) although in our application it needs to be somewhere in the middle so it's a bit academic anyway.

I seem to remember clamping a length of B&Qs finest square section ali tube (6mm maybe?) to one sprocket to check the alignment (with any necessary allowance for the different thickness of the two sprockets) as they not only need to be in the correct transverse position but of course they both need to be pointing in the same direction. I though I took a photograph when I did it but can't find it now :headbang:

Alan
1953 AJS 16MS, 1939 BSA 250 and a 1/3 scale Sopwith Triplane but that's another story ..... :lol:
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