Anyone know how much oil goes into the carb pots? SU HS4 1 1/2

[NonMember]

20 minutes ago, clive said:

I know when Honda were playing with lean burn tech they used very weak mixtures. I am sure I heard 18 or 20 mentioned

Yes, if you design the combustion chambers right then it is possible to persuade a petrol engine to run 18:1 or even 20:1 for cruise. Apparently the Dolomite Sprint engine is actually surprisingly happy with lean mixtures, though I doubt that was intentional. The other way to run very lean is GDI, because you can do stratified charge - the bit that's burning is locally a bit richer at the start of the burn, which helps avoid misfires.

[daverclasper]

So, worth trying a thicker than 20/50 (if I have some about), or will any increase in acceleration power be negligible anyway, I assume?.

Edited August 21, 2021 by daverclasper

[NonMember]

The dashpot oil is there to provide enrichment under "transient" conditions, i.e. within a second or so of opening the throttle. Too thin and you get a weak mixture, hesitation and a "flat spot". Too thick and you just waste fuel. Engine oil gives the right correction. You could try thicker and it may make a tiny difference but only to the way the engine responds to transient events. The actual power you get for the overtake all happens after the dashpot has finished its job.