You are here:

MG Car Repair/SU Carburettor jets


Hello Mr. Jones
My query is regarding the jets for the SU carburettor.
I have a pair of used, good condition 1.75" SU carburettor complete with needles but without the jets.

I happen to have a few sets of old stock but unused jets for the 1.25" and 1.50" SU carburettor around. Physically they fit nicely to the 1.75" SU carburettor but I am wondering whether they are suitable for the needles of the bigger carburettor. I know the jets come in 0.090 and 0.100 sizes.

I would appreciate your views.


Hello Yahaha

In general, 1.25 and 1.50 carbs used .090 jets, but the 1.75 used larger .100 jets.

Try inserting the needle from your 1.75" carb into one of your jets.
If you insert a .100 needle into a .090 jet, the needle will be too big, so it will not go fully into the hole.  

MG Car Repair

All Answers

Answers by Expert:

Ask Experts


Barrie Jones


MG Sports Cars from 1949 to 1980 - Including MGB, MGBGT V8, TF1500, TF, TD and modern Midgets. I also specialise in SU carburettors, Lucas wiring, suspension, steering & brakes.


I have owned my 1955 TF1500 since 1966. Technical specialist for the TD and TF with the MG Car Club T Register. Also owned 20 MGBs and currently own an MGBGT V8. Written 3 books on MGs and produced a DVD on how to strip and rebuild the TD/TF gearbox.

MG Car Club.

Barrie's Notes on the 1953-55 MG TF (author). /=====/ Barrie's Notes on the MGB (author). /=====/ Barrie's Notes on the MGB GT V8 (author). /=====/ The Essential Buyer's Guide to the MG TD, TF and TF1500. (author)

M Phil, C Eng, BSc (Eng).

©2017 All rights reserved.