High compression Carb and Low compression Carb, Difference?

[TtownJoeShow]

Hey, normally i'm good at figuring this kinda thing out, but i can't see why a carb would be set up differently for a high compression engine, other then jets because ya might be usen race gas.....

what do you guys think?

[barrett8]

more compression = more heat so you bike will run lean if you do not jet it richer

[riverrat]

Engines are air pumps. Carburetors work off the vacuum created by the "air pump". So if you change the way the air is being pumped, you might have to change the fuel/air ratio(by jetting). That's it.

[riverrat]

more compression = more heat so you bike will run lean if you do not jet it richer

Not true. I had to jet down. I was told because high compression engines are more efficient, they use less fuel. Not sure if that is the case universally though. Cars with higher compression engines get better gas mileage, I remember that from my hot-rodding days. Heat is not the determining factor in how lean your bike is, it is only one piece of the puzzle. Yes higher compression can generate more heat, that is why your cooling system must be up to snuff, and sometimes needs to be upgraded, but it doesn't mean you are running lean, after switching to high compression.

[ceaserthethird]

I like this info, when going up in compression you'll need to
Run Race Gas.

[jrsqlc]

I like this info, when going up in compression you'll need to
Run Race Gas.

this is NOT necessarily true at all!! i called wiseco about my 12:1 piston for my 350X and was told NOT to run race gas.

[ceaserthethird]

2 strokes yes

[TtownJoeShow]

interesting stuff guys!!!! thanks!!! i suspected the jetting was the only difference..... i like the high comp piston not needing race fuel for a 4 stroke, might have to investigate that!!

[jrsqlc]

yes do investigate all you can for your model and app