MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Carbs / Inlet manifold etc

Finally the beast has returned to the road, it is however obvious there is something not right about the carbs, the front one as a weird ie not vertical angle on the float chamber, if you tighten both dashpot screws down the piston gets locked and the jet is bent...

I have the original 2 x HS4 carbs on what looks to be a non oem inlet manifold - I found this when I went to apply all of Vizards mods to the inlet manifold and found mine was simply 'better/different' to the OEM one.

I have a spare set up of carbs bought second hand look a bit crusty - should I get a bunch of bits and send to Burlen or use this opportunity to convert to another card setup ?

The engine is 1275, high lift cam, hi ratio roller rocker, Peter Burgess ported head and lightened flywheel.

Ta
Malc Gilliver

Malc
To get the piston to drop properly it just needs the jet centering up--could you use the float bowl off another carb to replace the angled one if you have one suitable-
What size are the carbs on it now, you mention the originals were HS4's (1 1/2") but originals would have been HS2 ( 1/4")wouldn't they-?
William Revit

Sometimes just undoing the dashpot top and turning it so the screws mount through the next set of holes corrects the misalignment. Similarly, lift the piston up and down with one finger as you progressively tighten the screws does help. If neither of those sorts it, then centre the jet as Willy decribes.

If trying a differ carb set up the HIF44 really does work well on a modified 1275 like yours.
GuyW

The float chamber angle is set by the spacer between float chamber and carb body. Also what car the inlet manifold came from. Mini manifolds will fit midgets but you end up with a dent in your bonnet because a Mini manifold has a bigger angle than a Midget inlet manifold.

If you link to this page it's item 66 that sets the float chamber angle depending on application.

https://www.moss-europe.co.uk/en-gb/carburettors-5-twin-1-1-3-4-7-hs2-su-s-sprite-i-ii-sm--20--03--02

Rob
MG Moneypit

William - sorry they are the original HS2's - it was late !

I do have another set of carb - I was unsure about buiding a good set out of bits - I tend by nature to keep assemblies together - so that's good to know.

Guy - I have tried that - but as William as suggested using my spare set for spares I'll try that next - thanks.

Thanks Rob - I'll do some more looking into what I have and what it should be.

So next job is clean up and check the spare set and either fit that or combine.
Malc Gilliver

This thread was discussed between 04/07/2025 and 05/07/2025

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.