Trouble starting ’40-42 16H Norton M/C

[Chris Preston]

'Evening All,

We have a 1940-42 Norton M/C in our museum's collection that we're working on getting back on the road again after some time sitting on display, but it's challenging us every step of the way back to being operational again. The following is in the words of the chap who's working on it:

"It's extremely difficult to start the motorcycle. The engine will turn over easily and appears to want to catch but won’t engage without difficulty. Continuous adjustments with fuel, advance and air have little effect but engine will backfire occasionally when trying to start. Lately, the backfire is getting very noticeable. Spark is good but plugs show carbonization. I suspect mixture is lean but backfire suggests rich? However, when the motorcycle does start (once every 5 min and 50+ kick starts) it runs very well for 20 sec before stopping. No amount of throttle adjust/control will keep it running. For those 20 sec of running it sounds very good and the bike can be revved with throttle. But at the end of that 20 sec it simply quits.

Spark appears good, and the points were adjusted and spark is good, but I am not convinced that the advance/retard setting is correct - movement is free, but seems to only go half way. Compression is good; gas is good, and so are the oil levels."

Any advice would be greatly appreciated.

Sincerely,

Chris Preston,
Ashton Armoury Museum,
Victoria, BC, Canada