steel vs fiberglass tank size

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I just laid my new (used) steel commando tank on the bike prior to mocking up decals and finalizing a paint color.....what's apparent is that the steel tank is longer...if the tank is back enough so the forks don't hit it while going from lock to lock, the tank pushes my corbin seat up.....if the seat to tank gap is acceptable, then the tank hits the forks....damn...didn't think that was a possibility, ..my only choice might be to work the rear seat bracket to allow the seat to go back about 1/8, hopefully that will be enough to get everything to sit correct. anybody else experienced this?
 
what tank style are you talking about. Roadsters should be identical in fitment, Steel hold more fluid than glass, but otherwise should mate up.

Cheers Richard
 
There's about five different lengths in Interstate tanks. That's why CNW doesn't do them for the Interstate any more.
 
Any chance you can remove some of the forward rubbers to give clearance on the handlebars?

Russ
 
it's a commando / roadster tank....i will take the steel tank off the bike today and take some specific measurements....i did measure that from the front mounting studs to the petcocks.....the steel tank is about 1/2 longer but, that measurement doesn't matter if the front studs are in the same place...will take some pics also, thanks. guys.

i have an update...i just checked from above looking for a difference in size or shape....the front of the steel is wider / quicker than the glass tank which has a curve that is more gentle / sloped to the rear thus, reducing its front portion of width.....that may be what is causing the problem although knowing nobody else experienced this still pissess me off....WHY ME....WHY ME!

all of this probably wouldn't matter if the corbin was being utilized....the stock seat was never that tight to the tank.

just checked something else....although they may be the same in length, the glass tank's top is shorter and the top of the metal tank runs further back....this is for the added length needed for the glass tank rear knobs for the band / strap, so while they are they may be the same in length, the upper / applicable length is longer on the metal tank (maybe why it holds more)....the glass tank knobs fit under the front of the corbin seat so length wasn't an issue on the glass tank, now that it's known the metal tank has a longer applicable length, the corbin is the problem....or at least the majority of the problem....I may have to shave the front of the seat back a little to reduce its length....WOW, WHAT A PAIN IN THE ASSS........WAS THINKING IT WAS BE A SIMPLE CHANGE OUT....IT NEVER IS!

just spoke to Matt at Colorado Norton Works....he says the difference between the metal tanks regarding individual specs could be huge....there were 6 different manufactures during the day, all of which could vary enough to be causing the problem.....so it looks like i will have to shave some of the front of the seat to get it to work
 
Is it one of the 'seamless' MkIII tanks ? They are like loaves of bread. It's all dependent on how long they were left to rise before being put in the oven (or something like that !) There are no two alike of those. I had one expensively re-finished and it wouldn't clear the frame at the rear.

There's a thread on here somewhere with photographs.
 
don't know if it's a seamless tank...i know it sounds obvious but, how would i know?

bump bump bump
 
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