Need help identifying a gas tank to replace cap!

[timeconsuming]

Hey guys

So I have two gas tanks from a previous owner who had pieced together the bike from what appears to be a multitude of years/models.

Anyway one of the tanks is on the bike and the other is rusted pretty good so for fun I'm restoring it and one thing I'm going to need is a new gas cap.

Flash forward to mikesxs and apparently the standard vs the special have two different, inconveniently non-compatible gas caps that look pretty damn similar to my eyes.

My tank in question was a deep purple color originally which I believe could have been stock? No clue really /:

And it has a single petcock on the left.

Any guesses or suggestions on how to identify? I'll snap some pictures soon I swear!

 

[DogBunny]

The sure give-away is the gas cap screw mounting hole. Take a clear, close-up picture of that hole on the tank.

 

[Okie]

With a single petcock, it could be a Special tank. No way to tell without pictures.

 

[jay760]

Standard tank the cap is in the central, special/custom tank it's to the right hand side

 

[5twins]

Single petcock would be '80 or newer Special, that's if it is a 650 tank to begin with. Besides pics of the tank, show us the front and rear mounts.

 

[650Skull]

May help. First 2 pics are the Special cap and the second 2 are the Standard cap

Special tanks 78SE-79SF had 2 petcocks, and all 80-83's had one.

Standard Tanks from 76-79 have 2 petcocks and the similar type gas cap.

+1 what jay760 said