Tank Interchangeability.

[Mitragorz]

Will a gas tank off an '84 fit a '92?  I need a tank for my '92, there's a guy on Facebook with a couple tanks, he's says they're both off '84s but the one in front looks identical to mine.

[Pat Conlon]

Yes, the tank will fit. The tank petcocks are different between the '84 and '92 and are not interchangeable. However, you can use the '84 petcock (and tank) on your '92 by turning the lever on the '84 petcock to "P" (stands for Prime) this will allow the fuel to flow to the fuel pump without needing the vacuum signal to open the '84 petcock.
The '84 petcock outlet uses a 10mm fuel line and the fuel filter inlet on your '92 uses a 8mm fuel line, so you want to get a 10mm to 8mm fuel line adaptor to go between the '84 petcock and your fuel filter.

Personally, I would look to use another tank..the locking tank caps for the 84/85 tanks are rare.
The '86 to '93 tank caps are still available and the design of the recessed tank cap (with overflow) on the 86-93 tank is superior.

Have the seller take some photos of the inside before you buy.

Hope this helps.

Pat

[Mitragorz]

That does help!