B50MX Cold Start

Here's a cold start with my 1973 BSA B50MX Dual Sport Conversion. It's a low mileage racing machine with Lucas lighting and street legal!
The bike had sat for months before starting it here. I put fresh gas in it, cleaned the idle circuit in the original Amal Concentric carb, primed the carb...and it fired on the first kick! It's smoking a bit at first as it "wet-sumped" over the months, but in a minute or so the oil was returned to the tank (actually, oil-in-frame) and the smoke stopped.
Great bike! Very special!

[@delli6059]

beautiful machine,thanks for sharing

[@Beeza56]

Lovely! Thanks for posting. Have never seen this model in the flesh, not even at Oley.

[@DeloresGutkowski]

'Promo SM' 😢

[@HumberNorton]

No idea what the means...

[@BillyG869]

What’s that stupid exhaust about

[@HumberNorton]

Billy: That "stupid exhaust" is actually the original factory exhaust system on the BSA B50MX. It's admittedly, a stupid system, an extra 25 pounds of chromed steel on a lightweight racing machine, and I have no idea what the "geniuses" at BSA were thinking while their whole empire was sinking in 1973. Maybe it had to comply with some noise regulations in the USA? Anyway, probably nobody raced their BSA B50MX with that double-megaphone system, and took them off. Then they got lost, discarded, etc. So the few with the original "stupid" exhaust are extremely rare and the exhaust system itself is worth $1000!