carb cfm size

What is the total size in cfm's of the 4 carbs on a 81ish 750?

 

RPM x Displacement = ?

I think anyway.

 

If I remember, it works out to 99 - 117 depending on the % efficiency you give the engine as a whole. However, when compared to the automotive rating standard, 2BBL and 4BBL carbs are rated at different vacuum levels.
Holley has a 2BBL carb rated at 500 CFM that is basically half of a 4BBL rated at 600 CFM. The XJ carb rack might be rated around 600 CFM or more (?) on that standard.

 

thanks, that's what I was looking for.

 

I day dream about making these Hitachi carbs into a boat anchor!
So I googled "motorcycle carb cfm" and found this.

http://www.nightrider.com/biketech/calc ... s_page.htm

here’s their formula

street carb cfm = rpm x displacement / 3456 x 0.85

81 750 Seca

9500 X 45.64 = 433580 / 3456 = 125.45 X .85 = 106.63 CFM

ab

 

If you note in albran's formula the 85 % is the efficiency rating.
This formula is what the engine flows, but not what the 4 carbs together would flow- - let's say into a V8 engine.

In theory, a single Hitachi could run the bike if hooked to a common plenum (would need to be re-jetted)

 

after viewing the responses on pods, airboxes, and these hitachi carbs, I've decided to experiment a bit. I'll be using some weber carbs (old sand rail project), a dual cable throttle from my Norton spares, and a homemade intake. It's going to take awhile, but since I'm retired, time is not a concern. When the "gotta ride" feeling hits, the Norton will handle the urge. If nothing else, it'll be a good time in the shop, and could end up pretty wild looking. Might require an electric fuel pump, and a quick prime through the manifold (ala the old log ram mopar manifold).
Pictures will be non-existent, as I'm not savvy nor do I have the equiptment. Sorry.
Update. As progress is done, pics will be posted. I've been told this is the easy part, and I don't have to do much either. One of my buds will take the pics and show me what keys to hit.

 

aww man, where do you live? maybe another member could come by and snap a pic... for the sake of us all