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hi All. as above really sums it up.
T I A Mark

The 200 is 35mm, the 220 is 33mm.

220 is the Keihin PWK 33 and the 200 is the Keihin PWK 35

Here's the manufacturers website with info.

http://www.keihin-na.com/aftermarket/pwk/

Thanks .
that seems counter intuitive ?
the 220 having the smaller carb?
good info that.
although i read the spec for both carbs and it looks like they are the same size but jetted differently?
cheers mark

The 220 also has milder port timing. That, combined with a smaller carb results in better low to mid range performance. At least that's the theory behind the difference.

This also explains why different aftermarket exhaust pipes are recommended for the 220 vs the 200. Stock, both the 200 and 220 use the same exhaust.

Yeah, general rule of thumb is smaller carb for low end (torque), larger bore for top end (peak horsepower) (all other things being equal) and is why people always talk about the 220 being more of a tractor than the 200. Just basic physics, a smaller bore flows at a higher velocity than a larger bore. A really good explanation here. That is one reason for carb divider plates (as in the RB mod) as it decreases the effective bore at partial opening, increasing velocity for better torque/throttle response down low, but allowing larger volume at full opening.

bufftester wrote:Yeah, general rule of thumb is smaller carb for low end (torque), larger bore for top end (peak horsepower) (all other things being equal) and is why people always talk about the 220 being more of a tractor than the 200. Just basic physics, a smaller bore flows at a higher velocity than a larger bore. A really good explanation here. That is one reason for carb divider plates (as in the RB mod) as it decreases the effective bore at partial opening, increasing velocity for better torque/throttle response down low, but allowing larger volume at full opening.

thanks buffy, i am saving my pennies for a bunch of RB upgrades.
cheers mark