How To: Make a jet block extractor

A useful tool to press out the jet block when stripping a pre-Monobloc Amal carburettor…

 

1: To clean the jet block requires removal, but it’s fairly delicate – driving it out can distort the structure. Pressing is a safer option, but the base of the carb offers little support...

Step 1.jpg

2: I made up an aluminium ring with the correct diameter and 26tpi thread to screw onto the threads on the bottom of the mixing chamber, for the bottom nut.

Step 2.jpg

3: That gives plenty of support to put the carb body into the arbour press and, using a piece of aluminium bar down the middle, press out the jet block without excess force.

Step 3.jpg

4: There we are – although it was quite corroded, the ring has made it possible to press it out controllably instead of battering away and causing (probably irreversible) damage.

Step 4.jpg