Monday, 30 June 2014

Always a good idea to try positioning new bare flywheels with a length of wooden broom handle in place of mainshaft to check all is approximately as calculated. Not least the available distance between them for the conrod !

A crack in the originals can be clearly seen close up running towards the mainshaft from the oil feed outlet on the inner wall . Probably would not get much worse if only subjected to light road use but sprinting is too much of a risk.

Norton simply used cast iron for their road going OHV singles so it is to be expected that after a half century of use this might be weak spot to reveal itself.

Found a use for old CD or DVD discs. Download a timing disc from the internet and glue it on. Although in theory the bigger the diameter the more accurate the reading I find that it is more easy to mark zero for TDC without making up a bit of stiff wire and finding a place to attach it.

Thursday, 12 June 2014

The original Norton piston looks more to do with the steam age than modern items. I have invested in a Wiseco forged piston which looks a more serious a component. It was designed for a Triumph and the difference is obvious being the pin size and the compression height; being the distance from the top face and the centre of the pin. I can handle these issues however with a new bush and a longer conrod. The valve pockets are however a little high and  must deal with this .

The beauty of a modern high performance piston is beguiling.
 The standard of machining is space age. 
A work of art.

Saturday, 7 June 2014

The tappet follower which was designed (right) after the Norton factory decided to move away from having a lever type tappet was good for several years from the post-war era until they had a minor re-design for the alternator models. It is not difficult to see why the design had a much more substantial thickness as any attempt to remove the thinner item would break the the factory must have discovered themselves.

When Pierre Vernier invented the vernier scale he must have known he was onto a good thing. As I belong to the generation of people who used slide-rules before calculators came along the idea is very familiar. However just as slide rules were referred to a 'guessing sticks' so vernier callipers were called " very- near" callipers. The big change was when they became digital and I now use it constantly.