Interstate tank?

[Dad]

Hey all. Friend gave me a set of V Stacks. Tried to put them on my 99 tour and they hit my tank. Have only read of this issue with an interstate tank. Short of draining and checking capacity is there a quick way to know if previous owner switched tanks?
Thanks

[Hook#3287]

I'm guessing here, but, the I/S tank is wider, so a tape measure should do it.

[Hook#3287]

I hooked a tape measure to the bottom lip of the tank on the right and to the center of the standard/tourer tanks gas cap it's 19"

I/S is 20"

[MP]

Put a spacer under the front tank mount to raise the tank up some.

The regular tank does not have much of a rise where it meets the seat.  The IS tank has a lot more vertical rise.  Once you se the difference, it is easy to spot.

[John Schmidt]

Yes, look underneath to see if it has either a sending unit for the I/S fuel gauge, or at least a block off plate where it goes. It would be mounted in front of the petcock.

[BF]

BigBF sells a spacer kit with the correct bolt just for the velocity stacks.

[Dad]

Thanks for the feedback. Will check it in the morning. Looks like I need to install a spacer either way.