CFM of throttle bodies


Jun 23, 2006
Hey ya all,
Does anybody know the CFM of the throttle bodies? I'm trying to figure out if a bigger filter is worth my time or not. I will be calling Triumph dealers tomorrow, but they take a while to get back to me. I'm thinking somebody has an answer.
Tall Tx Guy
Thank you Pig9r.

I'm trying to come up with a rough idea of what the Rock's CFM is and what size filter I need for that MGS airbox. The single RU-2780 is able to deliver well at low RPMs but struggles at higher RPMs / higher HPs because, I think, its CFM is somewhat limited compared to the Rock's peak CFM.
Are talking about fitting a single 2780 on the intake? You might have issues then. I never have noticed any problems with the triple 2780's under the bearclaw. Dougl contacted K&N a while back and got some info from them. While the 2780 had less cfm flow than the others they said you can expect better results because each throttle body is fitted with a filter.

OK I found Dougl's post... Link Removed

Here are flow rates for various K&N filters I got from Leon Collins at K&N. The values are in cfm @ 1.5" water.

RU-2780 191 x 3 = 573
RU-1700 263 x 3 = 789
RC-1250 207 x 3 = 621

TB-2204 (under seat) = 680

Can't find CFM of RU-5111 (undertank).