46 Fuel Tank

[Steve64]

Hi everyone, I hope all is well, I am having a bit of trouble with getting a tank for my matchless 500, 1946. I am after some info about the frame and mounts. I would hope that someone would be able to provide the measurements for the mounts, pics supplied, centre to centre of each one. I have found a tank that needs a heap of work but the mounts are way off and I can at least discount it if it is wrong. Also the front part of the frame I purchased that I thought was a 46 has been dated by the frame number as a 59 model. Any help would be greatly appreciated.
Thanks ,Steve.

[Mollbhan]

I have a 48 500 single, width between the centres at the front 130mm at the rear 165mm, measured with the tank in place may not be dead accurate but pretty close.

[Taid]

Bearing in mind it was built to imperial dimensions that was probably 5.125 and 6.50 inches ..

[clive]

Steve64 I imagine the tank you have is from a later model when the front mounting points are straight across more like your rear ones. Not sure how that can be adapted without some significant welding and panel work on the underneath. However a good panel beater could cut the bottom out and adapt it before welding it back in. Experience from our section is that if it is then pressure tested you must bolt a plate across both the front and back mounting points. If you don't do that even a relatively low pressure can spread the tank throwing the mounting holes out of alignment again. Something to do with the way the shape reacts to internal pressure.

[Steve64]

Thanks guys for your reply and advice, I will add a picture of the tank for some feedback and advice from people with more knowledge than me.
Thanks again, Steve.

[clive]

Show the underside as well as the top as it will help identifying the year.

[Steve64]

Here are a few pics of the tank, I hope this helps with identifying. If you line up any hole with the frame none of the other 3 line up, I suspect, probably stating the obvious that some mounts have been moved to suit another machine but saying that when I line up with my frame all of the mounts will be right on the outer edge of tank. Thanks for all the help, greatly appreciated as always.
Steve.

[clive]

Well the tank is piecrust cap type but I think it could be 49 as it appears to have the stoped front to the right hand cutbout (as fitted on bike left hand) as we looked in the picture this allows the operation of the valve lifter which was moved to the rockerbox that year. The front mounts are wider and straighter I think on that year.

Edited as I got my left and right confused!

[Dungie62]

Steve, completely off topic but I must say the finish on your frame looks excellent. I am at the point of refinishing my 51 G80 frame. I was going to have it powder coated but thought the biuld up might prove difficult at the frame joints and engine plates. I am currently leaning towards two pack. So my question is if your frame is powder coated, did the thickness of the coat cause any issues? What ever it’s coated in it looks great. I could get you tank mount and frame measurement off my 51 if that would be of any help. Regards Dale.

[Steve64]

Hi Dale, no problem with off topic if I can help in any way I will, this site has helped me a great deal. I had my frame and all of my paint in 2 pack, the finish looks great I must say. The thickness was fine, I taped up the external threads and re tapped the internal ones with no problem. I was lucky I know a great painter, if its done right you will love the finish. With the measurements it is all helpful, it helps me narrow down what I have. Good luck with it all.
Cheers, Steve.