Re: repro vs original carburetor jets

Posted by Doug Linden on December 06, 1996 at 14:46:19

In Reply to: repro vs original carburetor jets
posted by Wayne Parker on November 18, 1996 at 16:30:06

: While rebuilding a carb and comparing the repro jets to the original jets, I noticed that the repro jets have a different shape on top - kind of like a bullet as compared to a concave shape on the originals. Will this have any effect on carb performance? I think I may use the originals instead of the repro jets from the rebuild kit. Does anyone have an opinion on the repro jets as to their quality and flow performance? If I use the original jets, what is the best way to clean them without damaging or enlarging them.
I have found that the originals jets can be brought back to their original performance with a little patience. Paul Moller's book is invaluable and a flow tester is a must.
A bunch of us got together one afternoon and we all tested and "adjusted" our jets. It took some time to get the orifaces right. We found the best way to adjust the oriface was to use a small collar for a lathe which would squeeze the oriface down in size and we use pin gauges to find the proper diameter hole. Our experience was that all the jet holes were too big, not too small. We also redid a few jets because we didn't like the flow pattern of a few jets. We can't verify that a jet that didn't have a nice looking stream of water worked any better than one that looked funny.
As a note we found that all the repro jets we looked at were nowhere near the flow that was specified. Some were too much, while others were too little. I'd stick with the original jets.
It's been 3 years and the carb still works as good as that afternoon I put the carb back on.

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