Is this Normal?

[greyghost]

got a quick question

I've just changed from a Standard Cast inlet/exhaust manifold to a Janspeed tube steel inlet and a Maniflow 3 into 1 extractor exhaust.

the pervious needle in the carb was a DZ, i started with a 6 and have had to put an MME in to keep the car cool.
the car was running well with the 6, but was getting too hot. its winter here and and i'll just melt it in the 45º summer heat.
so now i'm running an MME and the car is much cooler.

this just seems a very BIG needle for a slightly over-bored 850, wouldn't you think.

[JC T ONE]

The more "flow" you get, the fatter/richer the mixture need to be.
When the engine runs lean it gets hot hence burned exhaust valves(if you dont adjust it)
plus the cast manifold "transport" more heat away from the engine

[greyghost]

cool i thought as much, it just seems a big jump in needle size, thats all

[mk1]

I agree, it's a big old needle but if it feels like it's right & the car is running cool, I'd leave as is.

[guru_1071]

dont forget you may need to swing the dizzy a bit, which will help with the running temp

[greyghost]

Guru,
I shouldn't have to move the dizzy much, as everything else is exactly as it was when it was parked up.
only the manifolds have changed. but ill through a light in it to check.

Mark,
yes it is running well and "strong" so i'll live with it.