Year of manufacture help on an N15CS

Hi
I am working on an Norton N15CS. It has different numbers on frame and engine.
I am trying to identify year of manufacture for the engine number, which is N15CS/116075.
The frame number is 114166.

I will most likely have some questions in regards to the front forks.
This machine has been "chopped out" back in the day and then left unfinished and it is now desired to be restored to original.
The front end had 6" over front fork inner tubes and some non-Norton inner dampers with modified extended fork damper rods. As such I have limited knowledge on what should really be inside. My other projects have been girder forked or Commando's, I have not had the pleasure of this era fork.
I understand that this would have fork inner tubes that were approximately an 1" longer than standard and a longer damper body and rod. Which I have now in hand. Per the owner, it had the rubber gaiters when he bought it (used from a dealer). My understanding is the use of rubber gaiters started in model year of 1965 or 1966? Can anyone confirm?
However some of the other internal bits I have questions about. I have attached two images to use as reference. Numbers in () will be from the first image and numbers in [] will be from second image
The first was given to me marked for P11/G80 and the other is taken from the parts book for 1963-1965 for models 88ss, 650ss, 650/99 and Atlas and has a separate section for 1966, 67, and 68 for the 650SS, Atlas, N15CS, P11, G15CS, etc.

http://s225.photobucket.com/user/Norton47/library/Norton Technical
http://s225.photobucket.com/user/Norton47/media/Norton Technical/63-65 Atlas Fork IPB.png.html


So first question. Which of the two fork IPB would make the best base line to work from?
Second, should the headlight ears (20, 51) and [31,31] have cutouts on the inside to allow them to slip over the lower triple tree?
Third, should these headlight ears be sheet metal or cast?
This image from a Norton Owners Club calendar from 1994, I think is what I am trying to recreate.
http://s225.photobucket.com/user/Norton47/media/Norton Technical/N15CS Curzon Front End IPB.jpg.html



Thanks in advance for your time

This diagram shows I believe early Norton twin forks with the curved headlamp ears;

http://s225.photobucket.com/user/Norton ... B.png.html

Later 750 forks had different ears;

http://s225.photobucket.com/user/Norton ... B.png.html

The Norton N15CS was NOT in a f/bed frame like the Atlas.
As these were made at Plumstead after they shut the Birmingham, UK factory down, there was a lot of “mix and match” with the AMC/Matchless components using the Atlas engine, matchless frame Norton or Matchless forks e.t.c. ;

http://www.nortonownersclub.org/models/hybrid

Bernhard
Thank you.
I have several articles on the N15CS and G15 series by Paul Morin and Anthony Curzon, both of which even more in depth information of the mix and match of the various years of these hybrids. The NOC article is rather general. For those interested http://archives.jampot.dk/Editorial/Scramblers/The_Atlas_Hybrids__From_G15CS_to_P11_(Paul_Morin).pdf

There are not any illustrated images of the N15CS forks, that is why I was inquiring as to which IPB might came closest to an N15CS, hoping that someone who had restored or worked on such might reply, as the information available indicates that they were built from Norton forks that were basically modified in length.

I was also attempting to see if someone could help with narrowing down which year of production for the 116075 serial number. It should be 1965 or 1966. There are differences between those years.
I have sent off to NOC for information on that year just trying to get a head start if I could.
Thanks again!

The G80/G85/P11 forks were AMC Teledraulics, as shown in your exploded diagram. These bikes used 1-1/4" fork tubes, but the parts (bushings, seals, springs, tubes, sliders) are different from the N15/G15.

The G15/N15 hybrids used long Norton Roadholders - the same basic forks as the Atlas and Commando, but about 3" longer than Atlas forks and about 1-1/2" longer than the Commando - others on this forum can give you the specific lengths.

AMC used Norton Roadholders in the G15/N15 series (sold as the Norton N15CS and Atlas 750SS, Matchless G15MkII, G15CS, G15CSR, AJS 33 and 33CSR)

The first series of about 300 bikes, built in '63 (G15CS/107xxx 'N' or 'M') had roadholders with teledraulic internals. From '64-on, they were straight roadholders with the longer fork tubes. The yokes were also Norton, mounted in the Matchless frame, as the Norton wheels (with 8", rather than the Matchless 7" brakes) required more room between the forks (7-3/8" vs 7"), with the 1/4" bearings, as opposed to the 3/16" bearings used in the AMC yokes.

If you are rebuilding N15/G15 forks, the parts are regular Norton parts for your late '65 frame, except for the longer (about 25") fork tubes.

Your engine is an early '66 which should be non-spigoted barrels, monoblocs, and magneto.

Hope this helps -

Bill