Newbie question magneto Dommie 99

Peter...yesterday there were at least two comments here...did you see them? If you deleted your own question to rephrase it, they probably went also.

I'd first try measuring how hot each pipe is on tickover when it is retarded most. Maybe the previous owner fixed it before you. You can buy cheap infrared thermometers. Handy in the house when cooking the turkey, or checking the freezer.

Don't swap the leads. Waste of effort unless you are fanatical about original appearance.

But then it has to be worth checking for equal opening angles. But I don't know acceptable tolerance...one or two degrees maybe?

hello your motorcycle a Norton Model 99 should be on coil ignition and the left hand cylinder should be set up with ignition lead the farthest way from from the rear of cylinders  And remember a four stroke engine fires once ever 720 degrees  so a twin fire only once ever 360  and the timing runs backwards  to the engine on the timing side and distributor cams can get worn at one side more then the other side and can be out as much as 8% so you need to re-check the timing with a good alloy timing disc  and a good timing light  with the pointer fixed to the rear cylinder barrel stud  and you need to rocker covers removed to see that at tdc you have all the valves are in closed position  then you can start you timing and you distributor rotor should b pointing to the oil tank and battery box for the left hand cylinder now most members will say this makes no difference but I have found over the 52 years of owners ship of a number of Norton twins  this dose make a difference  as ignition cams can be out even new ones can be out  now all the best yours  anna j 

hello the Model 99 were coil ignition from September 1957 to october 1962 when bracebridge street workshops closed  and that was the end of the Model 99 along with others  the only time the factory fitted magnetos on the model 99 was from september 1955 to 1957 from september 1957 the alternators where fitted and so was the coil ignition system with the prs8 ignition and lighting switch and d2 distributor  as standard and nothing was changed in 1962 until closure in october of that year and the only new machine for that year was the export Atlas 750               yours   anna j

... and the owner is happy with it, who cares what it left the factory with? (a rhetorical question as I think I know the answer.....)?