New SU float needles and seats

[swindler]

Hi all

I'm just about to replace the float needles with a new Burlen kit (along with fitting unsinkable foam floats as a precaution against ethanol after the solder on one of my brass ones gave way - on E5...). I've taken the first old one out and two interesting points. Firstly the tip on the old one looks to be intact but has stretched/lifted slightly from the needle. Second, and i've measured this a few times, the new one is shorter by 0.5mm overall. Put together this will mean the valve is closing with the fuel level about 1mm higher than before. I don't know how sensitive this is - the arms are set to the correct 7/16". Will I need to retune the carbs/reset the base of the jets?

Cheers

[christopher storey]

IMHO Highly unlikely to need alteration of float height, for these reasons :
1. 1mm is less than a 10% alteration in the depression of the float at shut off ( and a much smaller percentage of the mean "altitude" of the float above jet level

2.The buoyancy of the new floats is likely to be different from the original copper ones ( certainly that seemed to be the case with the ones I fitted to my Daimler 2.5)

3. It is virtually impossible to achieve a resetting to an accuracy of +/- 1mm

[abowie]

I'm with Christopher.

Just check that you have the float lever height set correctly. The jets should be fine.