Norton Model 7 plunger Frame 1949

I have never seen a complete bare Plunger frame shown in any Norton book. The best option is the RGM site which shows the later swinging arm version. I believe that Andover Norton offer a similar diagram on their spares site. The Singles Parts Book for 1950 has diagrams of the various alteranative chunks hung off some Norton frames of that era. Checkout pages 65 & 67.

If you have a copy of the 1949 -1950 Norton Model 7 Dominator Twin, Spare Parts list, this has some parts of the frame as a drawing. On page 24 there is the complete plunger rear suspension. On page 14 there is the front and rear petrol tank mountings. The only way to get what you want, would be get some one to draw that frame for you with all the measurements added to the drawing. I had this done for one of my Norton frames when I was restoring it.

I used a catalogue picture (yes I know it won't be accurate) to get dimensions for the toolbox on my ES2. I printed the picture then used a known dimension (wheel diameter of 19" to calculate the scale.

This was good enough for my purposes but maybe not for yours. Why do you need it?

Hi Denis,

   It's quite difficult measuring the frame tubes with accuracy as the lugs, being cast items, can vary in size. The frames were assembled on a jig and I doubt if the frame makers measured tube lengths much as they assembled them, as long as it all fitted the jig fixed points. 

   If you think the bike has been crashed you need to check the front down tube and the saddle tube (rear down tube) to see that the are straight in both orientations. You can do this by simply checking with a straight edge such as a steel rule. Next fit a loose but close fitting tube in the head stock and another in the saddle tube plus 2 for each of the plunger vertical spindle holes, at least 2 feet long so you can site them through to check they are in line. Then you need to get some tubes at least 3 feet long to fit in the sidecar lug holes, front engine lug and gearbox lug and the holes in the bottom of the plunger castings. this will allow you to see any misalignment and where it occurs.