Saturday, 2 August 2014

Crimps

Time to make up some fuel lines. I've got 14" of 1/4" ethanol resistant fuel lines knocking around, and some suitable crimp ferrules.


To make a good crimp, you need a little tool which you can buy or, with a bit of 1/2" square barstock you can make your own. The tool is just two 2" lengths of 1/2" square bar, clamped together and drilled for a 1/2" hole, such that there is a semicircle in each bar. V shaped grooves have been filed at four positions around the outside of the hole, and two short 1/4" rods set into the two halves of the tool maintain alignment.

Cut the end of the fuel line square with a sharp blade. Slip the ferrule over the end and push the banjo, tee, or hose tail (with the union nut in place) into the hose, as far as it goes. The fuel line, normally 1/2" OD, will swell out to something like 17/32".

Place the two halves of the tool around the ferrule and squeeze in the vice. The ferrule compresses the tube back to about 15/32", thus retaining it on the hose tail. It produces a better crimp if you squeeze it half way, and then rotate the ferrule/hose assembly 90 degrees in the tool, then finish the crimp.


Compressing the ferrule to less than its original diameter generates some 'spare' material, which swages out into the V grooves we cut. Here is the fuel tap end:


Here is the carburettor banjo:


And here is the non-standard 1/4" fuel filter. Judging by the cr@p I get out of my Bantam tank we will need this:



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