What I presume is the 'Gearbox Adjuster'

[AngleseyAJS]

Good afternoon,

I'm very new to the world of classic bikes but have always had a keen interest.
I've just acquired a 1955 AJS 18s. It's not been ridden for a few years but has been run periodically and kept in good condition.
As the summer has already gone! I thought it would be a good idea to go through it all and check everything over, we have found issues with the lights, battery and dynamo, no doubt that will be a future post!
On having a good look around I've found an adjuster is loose on one side, just above the gearbox. I've hopefully added some pictures to the post.
I think it's for adjusting the gearbox drive chain tension but I'm not sure so can't really search for it with out the correct term. The bolt is still visible in the hole and does move if you touch it.
Does anyone know how I get at the other end of it to tighten it back up, is there access behind the primary chain case? Does it all have to come off?
I'd really appreciate your help.
Regards
Chris

[dave16mct]

Nothing needs removing but the gearbox fixings are hard to get at. The top fixing should be a bolt. Don't over tighten it and make sure you're checking the tightest part of the chain. There's always a tight spot on the chain. Better too slack than too tight.
Dave.

[AngleseyAJS]

Nothing needs removing but the gearbox fixings are hard to get at. The top fixing should be a bolt. Don't over tighten it and make sure you're checking the tightest part of the chain. There's always a tight spot on the chain. Better too slack than too tight.
Dave.

Thats for the reply Dave,

I'll wheel it out into the day light then for a better look. Do I access the bolt from the top or bottom?

[dave16mct]

Yes the bolt is at the top. Loosen the nut on the offside. You can get a spanner on the bolt head to hold it. The stud underneath is more difficult but sometimes you can just leave it, do the adjustment and nip up the top bolt. Then you'll have to adjust the rear chain. Are you absolutely sure it need adjusting?
Dave.

[SPRIDDLER]

Welcome, Chris.

If you don't have the factory manuals for your bike they'll be a great help and you can find them here under 'Books'................

http://archives.jampot.dk/

[clive]

David I think you may be talking about a different bolt to Chris. If you look closely at the photo the fixed end of the adjuster has come loose from the bolt. It is going to be difficult to reach the other end of that bolt to push it back into place and then turn the bolt to tighten it up on the adjuster block. I cannot remember how easy it is to reach and only have a rigid nearby to look at.
Chris it should be possible to get a spanner on the bolt head from above but it will be a fiddle. All the advice on adjusting the primary chain once you get it back in place is good.
Ps you do have some Whitworth spanners don't you as an adjustable is not going to fit.

[AngleseyAJS]

Screenshot_20230918_163518.jpg

The square part on the left of the picture is not attached at all the the frame and pivots on the right bolt.

Im guessing nothing needs adjusting as the right hole is elongated, meaning that's where the adjustment is and that end is bolted tight.

[AngleseyAJS]

David I think you may be talking about a different bolt to Chris. If you look closely at the photo the fixed end of the adjuster has come loose from the bolt. It is going to be difficult to reach the other end of that bolt to push it back into place and then turn the bolt to tighten it up on the adjuster block. I cannot remember how easy it is to reach and only have a rigid nearby to look at.
Chris it should be possible to get a spanner on the bolt head from above but it will be a fiddle. All the advice on adjusting the primary chain once you get it back in place is good.
Ps you do have some Whitworth spanners don't you as an adjustable is not going to fit.

Thanks very much Clive for the reply.
My dad is of a certain vintage to have Whitworth tools so I'm very lucky! What size would you guess at for the bolt head?
Ive had a go from the top but I couldn't feel anything so when I get it outside the garage I can have a look underneath.
I have a good strong magnet that I'm hoping might pull the bolt back through and I can hold it somehow while nipping it up.
Thank you for the help

Chris

[AngleseyAJS]

Welcome, Chris.

If you don't have the factory manuals for your bike they'll be a great help and you can find them here under 'Books'................

http://archives.jampot.dk/

Ahh thanks, I've had a quick look but it's hard on my phone to find the right one. I'll get the lattop fired up

[dave16mct]

I'll get me coat!
Dave