Amal Carb

eagle56 · Post by **eagle56** » Tue Apr 03, 2007 7:43 pm

Think I may have the wrong carb on my 18s 1952 ajay.

he Carb I have fitted is a 389/39 will this be the reason why on over run the bike bangs and pops.

TommoT · Post by **TommoT** » Tue Apr 03, 2007 11:53 pm

...nope, this carb should work fine on your bike depending on the jets and air slides fitted. The original carb would have been an 89B (I think), wiht the seperate float bowl, but the 389 Monoblock will work fine, set up correctly.

eagle56 · Post by **eagle56** » Wed Apr 04, 2007 9:37 pm

Thanx
i was told that the 389 was for a twin and the smaller amal was for the single.

I have since seen an add on the net wth a 18s with a 389.

Was thinking of changing it but I can save the spondooloo's for something else now.

itma · Post by **itma** » Wed Apr 04, 2007 9:41 pm

bangs and pops on overun are mostly air leaks in the exhaust system

ville · Post by **ville** » Fri Apr 06, 2007 1:33 pm

Hi

According to Dennis Wright's nice list at AJS & =M= Archives the size of that 389/39 is 1 3/16", when the size of original carb 89B is 1 3/32". Because of bigger size and probably too large main jet, your engine is getting too much petrol and part of it is burning in the exhaust.

This was just a guess...

-Ville