CARB pic and question on sizing

[skyeryder]

As long as I've been around R's I should know this one but I used to be scared of carbs:D , Where exactly do I measure at to decide what size carb I have???? Check out this pic below has anyone tried this and with what results?

[skyeryder]

That carb is a Keihin flat side PJ 07CACH i can't tell what the last letter is. Better pic maybe...

[tex250r]

Flip it over and look where your float valve is. Where the fuel cuts off there should be a number on that brass peice. Its where your floats push up your seat. Kind of like how jets are labeled.

Im pretty sure thats right? Might need someone to back me up on this one.

[jon370r]

You need to measure the inside diameter of the small end that is pictured. That Carb has been modified with some type of turbo swirl in the throat, maybe from Trinity Racing, so most likely its no longer the factory size anymore and the numbers won't give you the whole story. As for the swirl action, I don't see any benefit because the air starts and stops everytime the reeds open and close so its going to be drawn straight through the reedcage anyway due to its design.