They are quite easy to repair. The main problem is the brass contacts fixed into the plastic back piece get extremely hot due to corrosion causing excessive contact resistance and the contact sinking into the plastic. These can be drilled out and replaced with another contact (I machined one from a brass 'cheese head' screw). Alternatively, you could possibly use the back from a CB350K ignition switch (I do have one somewhere - I will measure it up to make sure). The yellow Zinc chromate-passivated steel housing is quite easy to replate, if you suitably seal off the non plated parts and the chrome key access part. The chrome part is a different matter as it is 'pot-metal' like the indicators and early alloy gas cap, which pits badly (welll in does in UK weather!) the steel part is staked onto this alloy part and I dare say they could be separated and then screwed together but its a difficult part to have re-chromed. I did not go this far as my chromed parts cleaned up OK. the connector cleans up OK but again the CB250 parts are the same I think. I am fairly sure you can get the crimp contacts, not so sure on the brown circular plastic housing. the U shaped moving contacts look the same as the CB550K to me but there again, I will measure and post my findings on here.
Or you could use the guy you are suggesting, obviously he does a good job. Personally, I like to tackle as much restoration as I can myself plus the fact I am a Yorkshireman!!!!!!!!!!
Cheers,
AshD
