I need to do some reconstructive work on the underside of my 1952 Twin tank. I thought this would be easy, but a quick Google images search threw up many different shapes and positions for the recess. Is there one that's right / best. Anyone willing and able to send a sketch that shows what's right showing all dimensions to allow sheet metal to be cut and welded.
T: Fuel Tank Gas/petrol tank underside recess position (not the UFM recess) and shape
- Thread starter Steve F
- Start date
I assume you are talking about the carb cutaway. I think there are THREE types; the early small recess, the later large one and the racing one. You probably want the later large one. My tanks are also being repaired but I can take pics of the underside tomorrow.
Fantastic. Looks like I have a B tank on a C bike. I'll re-do the carb. recess as the later C. I can scale the plan dimensions from the photo. Could you tell me the depth of the recess and approx. radii at the ends out of the recess. Is the recess flat bottomed or a constant radius from one end to the other ?
Steve,
This should help you scale it.
Sorry this last one is not a little better. The far wall is just under 2.5" down, but you can see that as the cutaway moves to the tunnel it tilts down and parallels the slope of the UFM. There are no sharp bends, just easy curves forward and back on the cutaway.
If you fool with it and need better photos or dimensions, just ask. I can take some shots in the sun light.
David
This should help you scale it.
Sorry this last one is not a little better. The far wall is just under 2.5" down, but you can see that as the cutaway moves to the tunnel it tilts down and parallels the slope of the UFM. There are no sharp bends, just easy curves forward and back on the cutaway.
If you fool with it and need better photos or dimensions, just ask. I can take some shots in the sun light.
David
You'll note that the "B" tank pictured has the lugs for the tie-bolt as security against splitting. My Comet did not have this in 1970. Racing along with a 350 A.J.S. I had a cool sensation in the ghoolies, and a burning sensation thereafter.I later found it not to be the original tank. Probably not many tanks lack this feature nowadays, but it is worth making sure if you want to have a thousand sons and live forever.
Steve, I am not sure that I would bother cutting your tank around just for originality, unless you want to win concours competitions. The B tank is a beautiful thing, carries a little more fuel, that comes in handy, the only advantage you will gain is a slightly easier carburettor cable run, but if you get Venhill to make you up some featherlight cables all should be fine.
I would also incorporate a an angled ferrule at the carb end of the cable.
I do not think an angled ferrule helps much as the cable run really wants to follow a U shape run as it leaves the top hat of the carburettor.
You just have to be more careful when fitting the tank to stop the tank sitting on the cable, as once it is bent it's all over, you can never get the kink out fully.