M21 carb upgrade

[maddogmargetts@yahoo.co.u]

I have a notion that upgrading the carboretter on my M21 to concentric from the 376 mono block may be a good step. I figured it would fit closer to the inlet due to the float chamber being underneath, this the dynamo went get in the way and I am informed the bike should run more evenly. Could anyone please recommend a suitable concentric carb for the M21?

[Spaceman]

If the 376 carb has a 1 1/16" (27 mm) choke size then the corresponding Concentric would be a 627. Might be worth borrowing a 600 Concentric to see whether it actually fits above the dynamo?

[maddogmargetts@yahoo.co.u]

thank you Spaceman. I did put a new 376 one on a couple of years back then i saw a youtube thing on cleaning them
in boiling water with bicarbonate of soda. Have you heard of this method?

[Spaceman]

I'm not a chemist but its possible that the bicarbonate of soda will attack the zinc in the alloy the carb is made from. The best way to clean a carb is ultrasonically but I tend to clean them with brake cleaning fluid, compressed air and suitably sized tube brushes to get into all the narrow passageways.