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amac carburetor


A friend of mine has a raleigh 500 sv model 21 of 1927 with an AMAC caburetor.
After the restoration we have a probleme starting the motorcycle.
The carb has been done by someone in england and the floater was replaced,we think, however after some experiments in moving the floater upwards a bit the engine finally starts and idles so we think that this is the probleme,the floater is too long and therefore the petrollevel too low.
Has anyone an AMAC carb type 15MD4/W9624 or similar who can messure the height of the floater, so we can adjust one.
There is almost no documentation on the internet about AMAC and we presume that they are slightly different from AMAL
Thanks for helping regards blackrider

These days old carburettors are often built from slightly mixed collections of parts, so we have to do the best with what we have!

My AMAC book gives model T. 15MDY and T. 15MDX as 1928 touring models with bottom and top feed float bowls, respectively, so maybe the "4" you quote is a mis-read of X or Y? Equivalent 1926 and 1927 models are PJY and PJX. "15" refers to 1 1/8" throttle valve - sounds about right for a sv 500.

Anyway, the plan should be to get the fuel level just below the top of the jet. From your description it sounds like this can be done - even if you need to modify the notch on the float needle or the clip on the float. An easy check for about the right fuel level is that the carb shouldn't drip if the bike is upright, but begins to drip if the bike is leaned over away from the fuel bowl. Test this with the throttle open (no needle bocking the main jet) but the engine not running!!!

Hope this helps. I can copy the parts list, but I doubt it would be of much use.


Hello Leon thanks for the info , the numbers on the carb are difficult to read but what I know the mainjet is 180 so that matches with  sv 500. the choke is the type like tt carbs with an open groove on the side.
Your plan sounds good and I will give it a go, thanks again I will let the forum know what the results are in the next weeks


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