Fastback seat & bodywork

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Jul 16, 2004

I am thinking about fitting the fastbackseat including tailpiece on my ’72 Commando 750.
The parts are available, though anything but cheap.
My question is, wether the Interpol-Petroltank fitted on my bike will cause me any problems?
In my impression the fastback-Petroltank seems roughly similar to the Interpol-Tank (shaped as Dominator Modell).

Thanks for the advice!

Greetings from Hamburg, Germany
Hello Matt,

The Interpol tank is the same length as the Fastback, but the tank is wider. The "ears" will need to be removed from the fastback seat. Otherwise everything else will fit nicely. Norton marketed this combination as the Fastback LR (long range).
Hi Ron!

Thanks for your quick reply! I thought the same when I first looked at pictures of a Fastback LR. Is there a possiblity that you can bent the ears outwards to make it fit, instead of fitting the LR seat? Well, it might look a bit awkward, wouldn't it? Giving it too much width maybe? I do like the looks with those ears.
Fasback seat

Instead of modifying a stock fastback seat you can get a brand new "long range fastback" seat that will fit nicely with your interpol tank.
It's been a while since I looked at the Interpol tank, but I believe there is too much width to spread the ears. Gary is correct, the seat is available already upholstered without the ears. They are made in England and should be available there, so you won't need to have one shipped from across the ocean.
Fastback bodywork

Hi Matt,

I posted the same message several weeks ago. My winter project is also fitting fastback bodywork to my '72 roadster. I have already acquired the parts for standard fastback. The seat came from RK Leighton in England who also make the Fastback LR seat mentioned by others. The hardest part to find is the rear fender of which there are two versions. For the '72 model range the fender has a notched out area to fit around the oil tank rear oil line connection.

I've got the tank and tail piece painted in original signal red waiting for clear coat....still need to paint the rear fender and fastback/interpol type side covers black.
Hi Matt,

The width of the fastback seat frame where the "ears" (knee pads) start is 9 3/4". I the width is approximately the same for the actual pads - I am not certian as someone chopped them off my seat. (before I was involved) :cry:
The repro fastback tank I have is 8 1/2" at the base, and 7" at the tie down lugs.
Actually, I have about 2" of the kneepads left, which brings me to my next Question:
Can anyone check the dimensions of the missing knee pads?
I want to weld the pads back on, but I might be tempted to go the LR route.

I hope that helps, there are pics of the new tank and old seat on my site.

arrgh... techincal problems.

Were the fastback tanks notched for the knee grips? Or is that an aftermarket thing?

Re: post above ~my site link is below.

illf8ed wrote: "The hardest part to find is the rear fender of which there are two versions. For the '72 model range the fender has a notched out area to fit around the oil tank rear oil line connection."

Actually there were at least three variations. I have one which attaches to the battery tray with only one bolt, one with the normal two holes for the horn tab, but no notch for the oil tank, and one as you describe with two holes in the front and the notch! Go figure!

Phil asked: "Were the fastback tanks notched for the knee grips? Or is that an aftermarket thing?"

All fastback tanks are "notched" for the knee pads. The only difference I have found in tanks is the '68-early '69 have the badge recesses where the later tanks were smooth for decals. Incidently, the best reproductions for these badges are made by Bill Giar, as I'm sure Greg Fauth (NORBSA) would testify.
Just a word of warning.. I went 85% down this road myself back inthe 1990s.. I scored an excellent second hand LR tank from RGM UK.

They also supplied a talipiece and side covers.

They did an excellent job of respraying the tanks and tailpiece.. including rust proofing the interior of the tank. They also got a new seat (LR) which was beautifully (internally ) supported/ upholstered.

That was the good bit.

The seat had CRAP ~ RUBBISH mount brackets.
The side panel (LH) was damaged and had no mount bracket! (They could not supply it.. )

They claimed the same cover was undamaged before dispatch.. the packaging was not damaged on arrival ??

The tail piece is NOT guaranteed to fit as many or most 850s have a different width rear frame. I had to 'file' out heaps of fibre glass to get the thing to sit correctly.

The misc brackets to mount the (cheap and nasty) tail-light replica were not to be found anywhere!

I could not find a replacement / original mudguard.. plastic/ glass !

The tailight/ number-plate plate was a pain as it was stainless and would not line up quite right.

While I beleive many of the small parts and guard etc are morereadily available now... I suggest tread carefully ~ even to the point of seeing the key components before buying..

I gave up and sold the whole package to a M/C journalist for $500 !!
Guten Abend!

Thanks for all the response!

I was made an offer for a complete Fastback-Kit (tank, seat, tailpiece) in pretty good shape for $ 500. I have not taken a glimpse at it, so I don’t know its real condition. That guy is a norton specialist, with tons of experience in his book.

Should I give it a try for that price or better leave it?

Guten Abend!

Definitely have a bo peek.. you may always regret not having done so..

But as suggested have a look in the tank for rust or corrosion. And ask him if he has ALL the bits required.. will the tail piece fit your frame etc etc.. IF not you an go back and pester the &^*&'er out of him, (unless he is a largish tattooed bad dude ofcourse)
And if he won't acept less.. you will be able to say you gave it bash ~ even if you decide against it!

Your choice ~ follow your gut feeling.. it is generally right..

Good luck!
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