Guy Barnes

29 September 2026 at 13:46 #84035

Hello,

 

I’ve recently acquired an M45 (which I love very much). It is generally in a fit fettle but is suffering from poor running/fuelling in the higher rev ranges. The carbs look standard – does anyone know the correct needles at all? It has KT needles fitted currently…

 

Many thanks!

Len Cozzolino

29 September 2026 at 17:00 #84036

Hi Guy,

 

The standard needles for the M45 are K.T. or WO 3  and 100 fixed jet (known at SU Burlen Services as Invicta jets!).  The carburettors are S.U. HV5.

 

If you go on the Burlen website, it gives the needle choice between weak, standard and rich.

Len

Guy Barnes

30 September 2026 at 11:10 #84044

Len,

Thank you, super helpful. Will get on the phone to Burlen!

Best,

Guy

 

L C Hannam

4 October 2026 at 09:59 #84072

“Normal” jets on my LG6’s HV5 carburetters, with a drilled fork at the base for choke lever attachment … the “Invicta” type has a screw there instead, to which is a knurled nut for jet height adjustment. These are generally fitted to downdraft SU carburetters with Thermo electric choke apparatus … thus my V12 has these jets.

 

Laurence