interstate/roadster

Apart from the tank, seat and side panels are there any other differences between the interstate and the roadster?
I have an 850 MK 11a. I've been gradually getting the above parts to make it a roadster.
The last item I bought was the seat, but it doesn't fit.
It is to slim for my frame. The lugs on the roadster seat measure 9.5 inches but on the interstate they are 10.75 inches.
Is this normal!
Anyone out there with a roadster or interstate, can you send me the measurements of yours to compare.
Something's wrong and I hope its not my frame.

cheers
chris r

no differences, until you get to the estarts with their hinged seats.

same basic bike, just the dressing changes.

Of course there are always exceptions, early fastbacks etc...

The seat position on the Roadster is easier on the hip joints as it further forward but the lugs should be the same distance apart just further back on the roadster seat to get the gap to the tank back. Range is shorter and in rural UK can be a concern.

Thanks for the reply but is it the seat or the frame?

chris r

seat

I hope it is but its brand new, bought from Wassels who usually know whats what.
I`ll see what they say.
Thanks again
chris r

10.75 is the correct size, there is something wrong with the other seat.

Yep that's a relief, just had it confirmed on the Norton owners club site as well. Will send seat back in the morning.
Thanks all for your help
Chris r

Not critical to seats, but the Interstates originally had different pipes and mufflers. The muffler was parallel to the ground rather that swept upwards. Lots of Interstates these days with the swept pipes. Mine included!

Russ