Concentrics and Monoblocs

[simon.holyfield]

Way back in the mists of time, when I had dark hair and less wrinkles, I bought a kit of parts to make a 1958 Huntmaster.

With that kit came a brand new concentric.

FB dwellers will know that the bits are painted and are coming back together at last, having been pushed to the back of the bike restoration queue for too long, so the end is in sight.

My question is, given that my FH would have had a monobloc and that I can easily look up the jetting for the monobloc, how should I jet the concentric?

[Steven.Carter]

Ahh,, mines got a 200 main jet,,, middle clip position. Best thing about a concentric is the tickler is easy to get at.

She looks very shiny

[simon.holyfield]

Ahh,, mines got a 200 main jet,,, middle clip position. Best thing about a concentric is the tickler is easy to get at.

She looks very shiny

Thanks Steve. That paint job would have provided a lot of us with new carburettors.

What concentric are you using? Do you know what size the slide is?

[Steven.Carter]

Its a 3.5 slide and its a 920 Amal, I forgot to say that

[dave.owen]

Surely a 926

[Roger Gwynn]

Surely a 626, 600 series 26mm choke. 926 does not exist! The starting point for this conversion is that Concs run about 10% richer than Monos so 10% smaller jets and one size smaller slide.