oil in frame tank mounting

[Grunt]

Hi new member here but I've been dipping in and out for some time now.

I am rebuilding my '73 T120V, it's been languishing in the back of shed number two for over 20 years and has got into a bit of a state. I've owned it since '76.  Over the years I think I've replaced everything except the frame and seat base. The first thing to go west was the engine, it spat a gudgeon pin out of the crankcase on the way back from a Blue Oyster Cult gig in Leeds! I replaced it with a T140 Jubilee engine, you could pick that sort of stuff up quite easy in those days. The rest was just wear and tear and a couple of prangs.

In An accident at the IoM  TT  in '81 the tank mounting on top of the frame tube was ripped off. I came off worse than the bike, broke my back and spent a good while in Nobles hospital. Any how I made a new bracket welded it on and suffered the consequences of a rush job until now. So I've removed it and I'm in the process of remaking it. However I can't find any dimensions of the bolt or the position it's in on the frame. I've got two measurements in my notes from over 30 years ago. One of 8.5" and another at 9.5" back from the steering head. And I think the bolt is 3/8" UNF.

Could anyone clarify these points for me?

Thanks in advance.

Grunt.

[L.A.B.]

However I can't find any dimensions of the bolt or the position it's in on the frame. I've got two measurements in my notes from over 30 years ago. One of 8.5" and another at 9.5" back from the steering head.

My '78 frame the bracket is 8 3/4" front, and 9 15/16" rear, back from the steering head with the slot a little over 1" long (open end at the front as early frames it was open at the rear).   

And I think the bolt is 3/8" UNF.

Assuming your fuel tank is the T120 type with the raised central seam in the top of the tank and therefore uses the chromed retainer and rubber bung, then the 'early' bolt is part S1823/21-1823 which is 5/16" x 3 3/4" UNF.

21-1823
http://www.ebay.co.uk/itm/PETROL-TANK-CENTRE-MOUNT-BOLT-5-16-x-24TPI-x-3-3-4-TRIUMPH-GENUINE-21-1823-/361079647127

However, 'late' T120s can be 83-4667, 5/16" x 3 1/2" UNF.

83-4667
https://www.rabers.com/item.asp?pno=83-4667

If the tank was damaged as a result of the accident and perhaps replaced with a T140 item, then a completely different set of parts would be required.

http://www.ebay.co.uk/itm/TRIUMPH-TANK-RUBBER-MOUNTING-BOLT-KIT-T140-BONNIE-TR7-TSX-TSS-TR65-71-83-00-0105-/301070843143

[Grunt]

Thanks for the incredibly quick reply L.A.B.

The tank is one of the parts that has been replaced, more than once. I currently have the raised seam type but it hasn't got any badge mounting holes. So I can't recall how I came to the conclusion but I think that it's a BSA tank. However I am toying with the idea of replacing it with a new UK made US style tank. But need to see the quality of them before I come to any firm decisions.

As far as the bolt is concerned it's just the diameter I needed. I will redesign the whole set up, making the new bracket with a closed slot, a one off machined nut with flats machined on it and a stud of the required length loctited into the nut once it has been inserted into the bracket. Ok it won't be original and may upset the purists but the whole bike has, over the years become a Bitsa purely because a younger me has done what he had to to keep the bike on the road.

Thanks again for your help.

[L.A.B.]

The tank is one of the parts that has been replaced, more than once. I currently have the raised seam type but it hasn't got any badge mounting holes. So I can't recall how I came to the conclusion but I think that it's a BSA tank.

It can also be Triumph if it is one of the early UK '4-gallon' tanks, as they had decals/transfers instead of metal badges, however, they are reasonably rare now because the early OIF tanks didn't have a reinforcing strap so they often split.


   

[Grunt]

because the early OIF tanks didn't have a reinforcing strap so they often split.

That's what happened to the previous ones even though they had the strap across the bottom.

I wasn't aware the earlier Triumphs had transfers on the tank. Thanks for the information.

 I also in the dim and distant past got a pair of replacement air filter covers which were made from ally rather than the original plastic ones, which had split and distorted to the point of being scrap. Because the ally ones never fitted properly I was thinking of replacing the complete side panel unit for one of the reproduction oil tank lookalike modern replacements. Has anyone got any thoughts on the quality of these panels, and the new fuel tanks.

Once again thanks for your replies.