Yet more mk3 seat woes.

Got another seat , now over 10 years since the norvil (useless) one was put in the rafters. It is as bad ! Have I got a rogue bike ? Think not. The original bracket is stepped, offset outwards and is visible well below the rim . Have the suppliers missed an obvious design necessity or is my bike a one off ? Help !!! Photos supplied. Roy.

L.A.B. said:

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L.A.B. said:

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AsI thought. Wrong hinge bracket welded onto base! Why would norvil, (les emery?) And now, blazing saddles not know about this? May need some very careful cutting and welding of new and old bracket as new seat cover is glued and not clipped. Unlike myself, people who don't consume large amounts of lager could be greatly stressed by these strange designs inbuilt to test us !!!

The seat with the rusty bracket doesn't look too far out.

Some of the replacement seats available ( pattern ones, i.e. wassel in my case) have brackets that are the wrong shape and in the wrong place. Looks like that is whats wrong here.
Cut off the old bracket, bend up a new one and weld or pop rivet in place. Bending up the seat hinge bracket is a pita, to get the bends in the right place took me a couple or three tries. Welding the bracket on requires the seat stripping. You can also trim the seat pan edge so it has the right profile so the trim strip doesn't foul the hinge.
I would think the new seats from AN will be a good fit. They certainly look well made, the pan pressing looks far better than the wassel offerings.

When I went to an interstate set up, I bought a used 750 tank and seat (also side panels, which im not using). I bought some of the correct washers and removed the mk3 hinge arrangement from the frame and went with the older hook bracket and screw tight method. It all retro fits to the mk3 without any trouble. I found it simple to get a decent fit and have since found it occasionally useful to remove the seat completely out of the way.

I was told by a very well respected Norton vendor that no 2 MKIII seat fits from bike to bike. That MKIII seats are not interchangeable and each must be sized and fit to that specific frame/tank.
He went on to say that Corbin is usually very insistent that they get hands on the tank at least before building an Interstate MKIII seat.

Yes not all MK 11 Interstate seats are alike , so matching up with the research is important . In my case the troublesome seat latch arrangement was ditched for the earlier pre MK 111 Interstate seat with the 2 screw down knobs . Happy .

One day in 1974 in an office somewhere in Hampshire UK, ''what could we do to really piss owners off? I know fit a hinge on the MK3 seat'' why change what worked before so well.

Mart UK said:

When I went to an interstate set up, I bought a used 750 tank and seat (also side panels, which im not using). I bought some of the correct washers and removed the mk3 hinge arrangement from the frame and went with the older hook bracket and screw tight method. It all retro fits to the mk3 without any trouble. I found it simple to get a decent fit and have since found it occasionally useful to remove the seat completely out of the way.

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I did exactly the same years ago.

Madnorton said:

One day in 1974 in an office somewhere in Hampshire UK, ''what could we do to really piss owners off? I know fit a hinge on the MK3 seat'' why change what worked before so well.

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Because the motorcycling press complained it wasn't up to date.

Seems I have a few options to mull over and have 3 seats to make one good one !!! Thanks for replies. Hmmm?

Lineslinger said:

I was told by a very well respected Norton vendor that no 2 MKIII seat fits from bike to bike. That MKIII seats are not interchangeable and each must be sized and fit to that specific frame/tank.
He went on to say that Corbin is usually very insistent that they get hands on the tank at least before building an Interstate MKIII seat.

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I very much doubt that. Improbable that there were variations on seat pans per bike . Seat pans come with the brackets welded so perhaps some bending tweaks ? I'm almost finished grinding, drilling , epoxying , trimming and fileing rubber on the rogue norvil "wassel" seat. Be very ashamed Mr emery !! Ps , the paint on the wassel seat seems to absorb moisture "hygroscopic" like brake fluid. What started off as a touch up is going to be a full repaint. GRIEF !!! It now fits ? May have to alter the grab rail !!! Nothings simple with it. Roy.

The yaki said:

I very much doubt that. Improbable that there were variations on seat pans per bike . Seat pans come with the brackets welded so perhaps some bending tweaks ? I'm almost finished grinding, drilling , epoxying , trimming and fileing rubber on the rogue norvil "wassel" seat. Be very ashamed Mr emery !! Ps , the paint on the wassel seat seems to absorb moisture "hygroscopic" like brake fluid. What started off as a touch up is going to be a full repaint. GRIEF !!! It now fits ? May have to alter the grab rail !!! Nothings simple with it. Roy.

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Yeah there are variations on seat lengths to fit the tanks , Interstate , roadster and Police models .
Just thinking about this and going for a ride today made me think the foam is now collapsing on mine , rider portion , passenger end is fine . What to do thoughts . ? I have drawers full of substandard parts , as ordered in new .

The yaki said:

I very much doubt that. Improbable that there were variations on seat pans per bike . Seat pans come with the brackets welded so perhaps some bending tweaks ? I'm almost finished grinding, drilling , epoxying , trimming and fileing rubber on the rogue norvil "wassel" seat. Be very ashamed Mr emery !! Ps , the paint on the wassel seat seems to absorb moisture "hygroscopic" like brake fluid. What started off as a touch up is going to be a full repaint. GRIEF !!! It now fits ? May have to alter the grab rail !!! Nothings simple with it. Roy.

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"The yaki".... As to whether you very much doubt my observations IDGAS.
I did not cite variations in seat pan sizing...
Read the information in the post.
I have actually interacted and worked with more than a few Norton seats both Roadster and Interstate.
The sizing of the seat pan and its configuration has a minor influence on fitting, but the irregular sizing of the Interstate tanks and how it fits the frame is the main influence in interstate seat fit.
Again. read the post.
That information came directly from Corbin and cNw. Corbin would not build a seat for me without the tank and preferably the frame.
After that information came forth I proceeded to buy out a collection of Norton parts, some still in original packaging including the side panels and tanks pictured below.
I was considering installing the original silver steel interstate tank and panels pictured to replace the fiberglass leaker that came with the bike. But, the building of a seat to fit correctly was more than I wanted to spend. I then ended up repainting the yellow Roadster tank and using it, for now.
The Silver Interstate tank measured out to an obvious difference from the fiberglass tank that came with the bike.

Pictured are a couple of the factory originals mentioned. Matt R might still have some of them.