[SEL] BSA 420cc engine

[Ted & Sue Domeney]

Hello All
Sorry not to reply sooner, but have been away two days. ( OT--- Travel across state, collect family piano from daughter who no longer has room to keep it, bring it home next day and store it in Dad's shed. That's what Dad's shed is for isn't it??, not for repairing and displaying smelly, noisy, dirty old engines).

Anyway, thanks for the good advice everyone.
I don't need a manual, but thank you Peter Ogborne for your offer. The information on original bore size was all I needed, 82mm. I wanted to know how much wear I was reading. It seems I have a "G" model as the engine number commences with G. 

I already have one BSA 420cc, but on that one I did not need to do any work on the internals (rings and bearings etc.) 

Back to the engine my enquiry relates to. The piston has a slight concave top. This (as has been said) would not affect engine capacity, but (if all other parameters are the same) would affect the compression ratio.

Jerry, the photograph of your colleague's engine is very good- a clever display. Some details are different between his and mine- principally the fuel tank-mine is round, or tube shaped. The oil breather dipstick (combined) and oil filler cap are different too. We have used pretty much the same colour. You can't get the colour I used, at the paint shop- it's a Tedmix.

Once again 
Thank you all.

Teddee