Powernow

[greenmonster]

Anyone tried?
Works?

http://www.frankmxparts.com/63mm-Power-Now-power-blade-37-39-41-Keihin-FCR-mx-carburetor
http://www.cyclebuy.com/shopping/powernow/press.htm

[koko64]

Very interesting.
I've seen them in a dirt bike catalogue.
They make me think of the auxiliary venturi in Weber carbs, but for flatslides.

[memper]

Looks like a V stack with a piece of sheet metal in it.
Anyone care to explain how this becomes beneficial? I always thought air was happiest with the least amount of turbulence. Perhaps the blade cuts down on that?

Got it:
http://crfsonly.com/reviews/powerblade/powerblade-250x.php

Lube for legless reptiles...

[koko64]

I was checking out the Dellorto manual and saw that their latest carbs have a feature which is designed to do what the powerblade claims, but is different. Some of the Dellorto carbs have a badge or heart shaped bore and throat, yep asymmetrical. The lower part is smaller and as the slide opens the larger throat and venturi are exposed. This gives the air velocity at small throttle positions and volume at wide throttle openings. It's doing the CV carb thing with a flatslide to get good part throttle response from a big bore carb which gives good peak power. It must work and be worth it because it looks tricky to make compared to boring a round hole.

Reckon the powerblade is trying (at least claiming) to do this by splitting the tract in half so you have a smaller carb at small throttle openings. The blade/vane would have to be on both sides of the slide and maybe even extend into the port to work I guess. No wonder they brought out the second blade for the other side of the slide. Guess if you bugger up the design it could promote turbulence.

Seems Dellorto's design is better (but understandibly pricey). Check out Dellortodirect.com.

[memper]

The Dels seem to have a much better solution.
Carb science can be so complex that it just doesnt seem that a plug and play solution like the blades would work.

[koko64]

Maybe the whole kit helps low end/midrange response. Might mean you can run a bigger carb with less compromise.
If it works it would make a peak power type carb more streetable.
Hmmm.