Velocity stacks blue or red????

[jic44]

Just bought a set of flatslide carbs and im wondering what is the difference in the blue velocity stacks and the red ones... If any! cheers lads.

[Mori Man]

Blue 50mm and spec'd for the FIII tuning (I use these)

Red 35mm and commonly used - generally with smaller MJ

You also get Black & Green too

[AFM327]

Anyone have a set of blue ones they want to sell? I need a new set of stacks and it would be good to compare the different sizes on the dyno.

[Mori Man]

Think I have this the right way round.

Shorter = more acceleration
Longer = more top end

If you look at drag bikes they usually run with 15mm or nothing at all on them eeking out every bit of power they can.

http://keihincarbs.com/special/STACKS/gate.html

They only ones that step out of this equation are trumpets made by Yoshimura which they call dual velocity stacks and these increase power through the whole range.