I have an xt2 with an axial .28 with an economical smaller venturi in the carb,
i was wondering if the smaller venturi which has less fuel getting in, more air gets in to the combustion chamber, having a slighlty larger venturi would add slighlty more fuel in and this would decrease the amount of air in the combustion chamber which would (By this theory) reduce engine temperature if there was a larger venturi?

Would this be true??

What? The larger the venturi, the more air gets in and the more fuel is used. Just like a real car...at least that's my impression.

I think those venturi inserts are of a help when you have a short track and too powerful an engine. They just reduce max airflow to make the vehicle more driveable (less power). For bashing, I'd remove it. You may have to re-tune a bit, but in theory you sholdn't have to, as the mixture sholdn't change. Less air coming in, makes it draw less fuel from the venturi and the mixture "should" stay the same.

hmmmm........I don't have much experience with these inserts....anyone else?

It's a pretty noticible power change when you remove or add a venturi insert, the tune of the engine does change ever so slightly, usually on the main needle. The temps change a small amount too beacause the engine is working harder when you remove it (higher temps) and when you add it the engine is working less due to an air flow restriction (lower temps) but not much...maybe 10-20 deg.

i realised i got it around the wrong way, the smaller the venturi less air gets in ( for some unkown reason i thought it was limiting the fuel getting in as it did in systems tech for school haha got confused) the larger the venturi the more air therefore more power with slightly higher temp..

cheers guys!