SLMLINE SEAT

Allan...nobody has come back yet so I'll dive in.

As far as I can tell the mudguards and seats remained much the same. Bacon's 'Norton Twins Restoration' lists just the one for all slimlines. The later ones had a hump at the tail but that's all. The rear mudguards were changed a bit. Early ones came down at front left just inside the swing arm but later ones had that bit of metal snipped away (possibly by hand with tin snips... Often they are a bit rough) to give more tyre space presumably. And Mercuries at the end were altered again with simplified pressings. But the seat pan did not change as far as I have observed.

But he does say the fixing before 1961 had two spring clips at the rear before the back Dzus fastener appeared. Hopefully someone else will explain before you regret drilling the guard. Maybe you are just missing the clips and need to cut off the later Dzus fastener item? Your ES2 cannot be much after 1961?

The Twins Restoration book might be useful as of course cycle parts were the same. Nearly....

One possibility is that you have a rear mud guard from a US export es2 or Manxman or early US export Atlas. Those bikes had a shorter and lower petrol tank. To make up the space the seats had the front receptacles and rear pins moved backward. This had the effect of moving the seat forward. The Dzus fastener hole in the rear mud guard was moved forward accordingly.

Hello well Can i dive in here as I own a very rare Norton Manxman 650 from december 1960 . And the seat is only 1.1/4 inch forward to the standard fitting , and I dumped the dzus fitting and opted for my 3BA screw fitting with a nice white knob witch works a lot better and no faffing about to do As you would with the dzus fittings , so your rear mudguard must be an oddball , And As for the Tank there Not lower but a better shape for your knees to fit to the tank and holds 2.1/2 gallons of fuel witch gives you 150 miles before the next fill up and is only an 1/2 gallon less than standard tanks and the Norton Manxman 650 seat comes in a very nice Bright Red seat cover with White piping to finish off its good looks and fit for any Royal posterior yours anna j

On my 1961 Model 50, the female part of the dzus fastener is exactly 5.5 inches forward from the pointed top of the rear license plate mounting (fairing) where it fits up against the mudguard.

Mike