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**The factory specs for bore and stroke (101mm x 112mm)**

I get a volume of

**54.7583 in³/cylinder.**

.7854 * (

**101**^2) *

**112*** (.1^3) * (.393700787^3) =

**54.75837050105755872 in³/Cyl.**

Converted to ft³ per cylinder:

**/**

54.75837050105755872

54.75837050105755872

**1728**(amount of in³ to 1 ft³) =

**0.031688 ft³/Cyl.**

So if one cylinder completes an intake stroke on each revolution, then just multiplying by the rpm will get us CFM at the rpm in question right?

**RPM * 0.031688 ft³ = CFM**

**2k RPM = 63 CFM**

3k RPM = 95 CFM

4k RPM = 126 CFM

5k RPM = 158 CFM

6k RPM = 190 CFM

7k RPM = 221 CFM

3k RPM = 95 CFM

4k RPM = 126 CFM

5k RPM = 158 CFM

6k RPM = 190 CFM

7k RPM = 221 CFM

(I went up to 7k because I have read some member(s) run em that high using computer/power commander based ignition control...)

Did I do the math right?

Assuming an generous 85% efficiency, because we all know 100% is impossible. That leaves us with

**188 PEAK CFM.... @ 7krpm!!!!**So we're pretty much getting

**134+ CFM on a stock bike at rev limiter**.

Seems like we could get that kinda flow with quite a few different air boxes, even the stocker? My only concern was for the ram air effect, but I figure that would be negligible without boost right?

Anyway, does anyone know the CFMs for the different intakes available and even for a K&N in the stock box w/ the pair mod done? I have money to put into other things for the bike right now(pegs/bars/risers etc.) and am trying to see what my best options were. Thanks in advance.