If using Windows on a PC, the default program will have a slider in the bottom right hand corner of the monitor with a – on the left, a + on the right. Move the slider to the right to zoom in. Alternatively, with the mouse cursor over the image, roll the mouse wheel up, away from your hand.
The roll pin is actually 3off, 2 larger ones and a centre spacer that is in the middle of the crank. Was going to not use them, but now am having second thoughts. After reading what David wrote, they could prevent the pulley pressing tightly on the flywheel because of a machining error on one of the associated parts. Rather than throw the batch away, fitting a roll pin was a more economic (bodge) solution. The ‘corrosion’ could be a type of loctite to prevent the flywheel moving in and out on the shaft. Am not sure about this. Going to grind the valves as I think this is the cause of the lack of compression, the seats look terrible because of years of storage with the valves open. When I re-assemble, will try to work out why the roll pins were fitted.
Have a 2a on a Colwood that I have had and used for 30+ years. The info I got all that time ago was the points gap is 0.018 – 0.020”, timing 30o BTDC. Have taken a picture of my points set-up and it looks the same as David’s. Believe mine has not had the cowl off since the day it left the factory, so it’s original. Can alter the timing by moving the armature backplate on the slots as shown in the photo. As the cam for the points is separate from the flywheel, can set the timing with the flywheel off. But expect it to be spot on as there is so little wear on the engine. Do not think it has done more than a few 10’s of hours since 1951.
Really pleased to hear Andy was approving of the external energy transfer coil trial. If it works, it should cost £25 max for the first one and £10 for the next 6 as the 125g roll of enamelled copper wire and a roll of heat resistant polyester tape will do several primary coil windings. Can get an external coil for under £6 if it purchased via Temu. It could save some old engines because it is so cheap to do.
