AJS & Matchless Owners Club

JPH wrote:What is the safest way to weld the tank ?, fill with water ?.

Rinse out any fuel with water then while welding, pipe in an inert gas like argon (available to most welders) or carbon monoxide (from your cars exhaust). Do not close the tank and work in a well ventilated area.

Rob C

I do not like the manner these tanks fasten, in an effort to overcome shortcomings I have threaded a length of brass bar then araldited it into the tank threads then use a nut on the bottom packing with the necessary rubber washers,
can you not slide a thin appropriate threaded nut behind the mounting and araldite this in place with the again appropriate threaded stud?
as an aside, from a suggestion by a member in Aus. my clutch chainwheel has the friction material bonded by means of araldite and has so far been very successful, kind regards

Epoxying in a homemade brass insert could work for me , all the stuff required is in hand.

Not hijacking this, but I thought I had a problem with the threads in my tank.

But it may support Rob's comment about variation. My tank bolts (three of which are new as I thought I might get a bit more purchase with them) are 1 - 1/4". As were the "originals" that were on. But when I slide the bolt through the penny washer, the flat rubber, the FAT rubber (complete with sleeve) it only emerges by 1/4" and add in the width of the frame bracket it sits on and when starting off there's hardly any engagement.

Consequently, the first couple of turns are very worn.

Further in, not an area I've often gone to as only learnt to just start to put pressure on the rubbers before wiring up, the thread is reasonable.

There's more scope between the back of the thread and the possibility of entering the tank than I'd thought. I'll be thinking about reducing the depth of the FAT washer - but with the utmost care and very careful measurement!! I have a feeling I should be using slightly longer bolts. The sleeve should help prevent disaster if I measure and leave a decent safety margin. Perhaps a full set of longer bolts would be more sensible.

Johnny B

On more than one of my bikes I have used mini exhaust mounting rubbers. These have a bolt at either end and need to be fitted in pairs as slightly thicker than the original rubbers. The bolt has a very similar thread but seems to lock satisfactorily even when the tank bolt won't do so. As the weight of the tank is above it and the lower bolt goes through the frame it does not matter if it only just locks. Only problem is that the rubbers and bolts do not remove so it is difficult to remove or fit the tank as it has to be lifted up. The handlebar clip with the 4 studs on the ally top yolk seems to get in the way but it's ok with the later 3 cap head clips.

56G80S wrote:Not hijacking this, but I thought I had a problem with the threads in my tank.

But it may support Rob's comment about variation. My tank bolts (three of which are new as I thought I might get a bit more purchase with them) are 1 - 1/4". As were the "originals" that were on. But when I slide the bolt through the penny washer, the flat rubber, the FAT rubber (complete with sleeve) it only emerges by 1/4" and add in the width of the frame bracket it sits on and when starting off there's hardly any engagement.

Consequently, the first couple of turns are very worn.

Further in, not an area I've often gone to as only learnt to just start to put pressure on the rubbers before wiring up, the thread is reasonable.

There's more scope between the back of the thread and the possibility of entering the tank than I'd thought. I'll be thinking about reducing the depth of the FAT washer - but with the utmost care and very careful measurement!! I have a feeling I should be using slightly longer bolts. The sleeve should help prevent disaster if I measure and leave a decent safety margin. Perhaps a full set of longer bolts would be more sensible.

Johnny B

By using longer bolts and going into the tank thread as far as you dare, that's your limit. Not sure if the rubbers will stay the same size. if they thin you have nothing more to tighten so will need new rubbers or extra metal washers.

as mentioned I won't use boltsalthough I'm sure they would not 'bottom out I won't take the chance, I only used brass bar because it was available, easy to cut and put a thread on and ,didn't have any correctly sized steel, which probably would have been more approropriate, by using this stud you can screw into the tank retaining strips and never hit the tank bottom, I actually use a feeler guage to make sure it is away from it, Clives mini exhaust mount is a good idea, kind regards

I think mini bobbins will be UNF 28 tpi not cycle 26 tpi. I still believe that if the tube is the correct length (checked by screwing in bolt through tube without rubbers and ensuring it doesn't bottom when tight) the bolt can be fully tightened when all assembled without doing any damage to the tank.

iansoady wrote:I think mini bobbins will be UNF 28 tpi not cycle 26 tpi. I still believe that if the tube is the correct length (checked by screwing in bolt through tube without rubbers and ensuring it doesn't bottom when tight) the bolt can be fully tightened when all assembled without doing any damage to the tank.

You may be right on the mini bobbins thread but I can assure you they fit nicely into a worn out thread and stay in place for many years!!!!!

I go with Ian. The bolts should be well tightened. Otherwise horizontal movements of the tank will jiggle the bolts in the tank screw thread and cause damage on the long run. Manuals say "screw firmly home...".

Albert