Interstate Tank Variations

rvich · Jun 23, 2020

Fullauto said:
This is why Matt at Colorado Norton Works stopped supplying Corbin seats for Interstates, for which he had the exclusive agency. 5 or 6 different Interstate tanks that he identified.

I've always accepted this to be true, but it suddenly occurs to me that I have never heard or seen comments that a stock Interstate seat did not fit properly with a tank.

Anybody here ever put together an Interstate and end up with a seat and tank that didn't match?

Or is it that the Corbin has to be a better fit to look right?

swooshdave · Jun 23, 2020

rvich said:
I've always accepted this to be true, but it suddenly occurs to me that I have never heard or seen comments that a stock Interstate seat did not fit properly with a tank.

Anybody here ever put together an Interstate and end up with a seat and tank that didn't match?

Or is it that the Corbin has to be a better fit to look right?

I believe that the different shapes at the rear of the tank wouldn't match up with the Corbin seat to Matt's high standards. That's my guess.

Interbak · Jun 23, 2020

One more measurement I forgot to include. The smaller tank is 13” at it’s widest point on the body, the large tank is 14.5” at the same point.

NickZ · Jun 23, 2020

I just noticed this thread.
I have a '72 with fiberglass tank. I am also assuming it is original.
My tank is identical to yours, Dave, even down to the smudges on the Norton stick on decal. The only difference I see is that I have a single gold pinstripe and you have 2. I guess yours is an 850.
Regarding capacity, I haven't tried to measure it. I had the tank coated so it would be less than stock anyway.

swooshdave · Jun 23, 2020

NickZ said:
I just noticed this thread.
I have a '72 with fiberglass tank. I am also assuming it is original.
My tank is identical to yours, Dave, even down to the smudges on the Norton stick on decal. The only difference I see is that I have a single gold pinstripe and you have 2. I guess yours is an 850.
Regarding capacity, I haven't tried to measure it. I had the tank coated so it would be less than stock anyway.

Lining should not be significant enough for this informal survey.

gortnipper · Jun 23, 2020

I bought this in the early 90s out of a newspaper want ad. Pre internet.

Full Length 24.5"
Rear 10.5"
Middle 14"
Front 10"

swooshdave · Jun 23, 2020

gortnipper said:
I bought this in the early 90s out of a newspaper want ad. Pre internet.

Full Length 24.5"
Rear 10.5"
Middle 14"
Front 10"

View attachment 17212
View attachment 17213

How is the paint on that one? Looks repainted. Is it just dirty or are there imperfections in the paint?

gortnipper · Jun 23, 2020

It is mostly just all dusty. There are some rub Mark's on the end of the tank from the new seat I got at the same time from the UK. I think those should polish out.

Since it was in rough shape and had a big ding in it, i had it repainted when I got it by a very good restoration shop that did high end vintage car work, as I knew them as they were down the block from me.

Ron L · Jun 23, 2020

O.K., late to the party, but I have measured my 3 steel I/S tanks and just for giggles, a fiberglass ('72) tank. Two of the steel tanks are similar to Interbak's black tank about 9 1/4 at the front, 10 inches at the rear, 22 3/4 long, and 9 1/4 tall. The third is like his blue tank, about 8 inches at the front, 9 inches at the rear, and 23 inches long. This tank was crumpled pretty badly and restored by metal wizard Ross Thompson, so these measurements may not be of use. I don't know what model year any of these tanks originated.

My fiberglass tank is 9 inches at the front 10 1/4 at the rear and 24 inches long.

swooshdave · Jun 23, 2020

The reason I was measuring the length from the steering stem notch back was because that measurement would affect the seat more than overall length.

Regardless measuring an irregular shape is always going to be interesting.

Interbak · Jun 24, 2020

swooshdave said:
I believe that the different shapes at the rear of the tank wouldn't match up with the Corbin seat to Matt's high standards. That's my guess.

I suspect you’re right. My custom seat follows the lines of the blue tank , with the black tank the rear corners of the tank stick out past the seat and ruin the flow.

Interstate Tank Variations

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