1st gen vf1000f velocity stack - are they necessary?

The velocity stacks on my vf1000f engine are fugly and torn due to being split and made to fit from a vf700 engine.

I believe due to the smaller diameter of the ones I'm using, restriction is causing power to drop off quickly at about 10k. This is when my buddy with his new 600 was able to pull past me, and it's simply not acceptable.

Does anyone know if these things are even worth replacing? Anyone have experience just running without them? Anyone ever make custom velocity stacks (what did you use).

 

Velocity stacks in general will straighten the air going in to the carb. It also keeps the air uniformed vs no stacks. Sometimes when air flows over top or comes in from the sides (because of turning) it can cause turbulence in the carb throat. Depending on the length/height of the velocity stacks they can help produce a "Ram Air" effect. Which can help greatly in the upper rpms. Depends on the total set up. The factory designed them for the motor so they most like help compared to not having them. I've never had mine off so I don't really know how my motor would perform without them.

I see they are still available, though a little pricy new. search the salvage yards/ebay.

OEM PARTS AND ACCESSORIES YAMAHA, SUZUKI, KAWASAKI, HONDA

 

I yanked the old velocity stacks and used 2 1/4" long pieces of 2" exhaust pipe to make some "new" stacks. I know their not as good as an aftermarket style, but per my research, i'm not too worried about a possible 3-4 hp loss on my 100 hp engine. And... the high RPM flat spot is gone!!!

 

I would probably stick with the OEM stacks, I've never heard of much to be gained by changing them. There probably is some room for improvement but it would take dyno time ($$$) as well as free time (what is that?) to figure it out.