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View Full Version : A little carb input needed. Help me decide.



RIDE-RED 250r
08-21-2012, 07:53 PM
I am running an ESR 350 big bore (78mm bore, stock stroke), ported for mid/top, ATC5 pipe and silencer, ESR reedblock (without spacer), race gas dome and 38mm PWK/AS.

What I'm wondering is this... Is my 38mm PWK/AS carb doing my engine justice set up more for mid/top as it is?? Would it unlock more potential by going to a 39.5, 40 or 40.5 PWK?

I understand that each engine has a carb size range best suited for it based on flow capacity and that going with a carb on the small side will give you better low end with a little less up top while going toward the larger size will give you more mid/top whele losing a little down low.

I also know that if you go so big that the engine just doesnt have the flow capacity to keep intake velocity up you will lose all around.

Just wondering if any of the more experienced big bore/mod guys have any input for me based on the way my engine is built. I like more in the mid/top range than bottom end. I do alot of gravel road riding where you are in the mid-top almost all the time. Low end is pretty much irrelevant to me.

Would I benefit by stepping up 2mm in bore from my 38? Or is the 38 already near the limit already?