that's why you can't tune 'em! Both jets should be the same size!
The only difference in part numbers (and front and rear)
it the 'handedness' of the fuel entry and choke hardware connection.
Check the two rebuild kits you have and you'll find the jets the same size.
They'll either be 0.09" or 0.1" diameter holes in the jets.
But both should be the same size. Otherwise the needles would have to
different to make up the same F/A ratio for the same mechanical
positions (# of flats down).
Paul Tegler wizardz@toad.net http://www.teglerizer.com
----- Original Message -----
From: "Ken Strayhorn" <ken@dukecomm.duke.edu>
To: <spitfires@autox.team.net>
Sent: Friday, September 01, 2000 2:52 PM
Subject: SU jets question
Friends -
I have a '72 MkIV that has twin SU carbs installed,
allegedly from a '70 model. They are impossible to
tune and I'm thinking that the jets are incorrectly
installed.
Fortunately, the DPO left a couple carb rebuild kits
in the trunk - but no indication of which goes on
the front and which goes on the rear. They are just
in boxes that say "Lucas rebuild kit" (yep, Lucas).
Using a pin gauge, I've discovered that the jet hole
(where the needle goes after it's all assembled) is
smaller on one than the other. Does the smaller jet
go on the rear, or the front?
Thanks for any help,
Ken Strayhorn
Hillsborough NC
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