Each motor compression cycle of your stock engine leaves a little residue getting sent right back into your motor to be burned up, somewhat decreasing performance and engine life.
Speed Dealer Customs claim that their kit doesn’t allow the sludge back in after it’s sent out to the filter. Included in the kit is the velocity stack. a set of breather bolts, velocity stack and a choke knob. The choke knob fits right in with the new velocity stack and bolts, with 3 settings full/half/off.
Available in Polished Aluminum, Black Anodizing ($138.49), Solid Brass ($219.49). Order online at Speed Dealer Customs (SDC) Tel. 417-717-4316
Can SDC back up these claims? I doubt these things have a long enough inlet tract length to smoothen or increase flow much,if at all,over just having nothing on the intake side of the carb.I imaging the mesh would play havoc with efficient flow rates.Any theoretical advantage of not sucking back some unburnt charge would be easily be outweighed by the ring seal damage by one good gust of dust.How can “it’s” go to the filter,when there isn’t a filter?
If you want something pretty,buy some thing.
What holds the mesh in?
I had pretty much the same thought. A little dirt in the intake is generally something that can “somewhat decreas(e) performance and engine life.”
As for the mesh, it LOOKS as if it’s teased into a groove cut into the inlet, right about where it begins to flare.
18Bravo,It says on their website that the SS mesh is placed in a groove in the face of the unit where it meets the carb’s body.I would not trust that method retaining the mesh securely on any motor I’ll ever assemble: On an old moped or two stroke weed whacker,maybe.
I used to run a velocity stack because psychologically I thought it would give me more horses. I never did “dyno” my bike before or after putting on the stack, but will express my feelings on them. These day’s, I would ONLY use a velocity stack when I’m on the drag strip. For the most part, I think it’s redundant, as there are many more carb applications that will boost horsepower ( wind forced for one). My experience with the stacks is like Terrence Tory said. I occasionally ride on dirt roads (sometimes it’s inevitable) and would cringe just thinking about the dirt and small gravel particles being sucked into my motor. Hey, If I can “feel” the dirt and gravel on my face…I KNOW some is being sucked into my motor! Aside from occasionally sucking my pant leg into the carb (no big deal, but it sure shuts the motor down in a BIG hurry until you pull your pant leg away) when I was putting my right leg on the forward control. Another thing, I had to carry a tennis ball with me (actually, I had it dangling from a rope under the carb) to stuff into the stack when I parked it. Though it was a chance to express my artistic side by drawing a picture on the tennis ball, it was kind of a pain in the butt. Like I said before, these days I wouldn’t use one unless I was on the drag strip. but then……These days it seems more about “looks” than the actual performance of your sled! For example……I have lived in Sturgis all my 60 years of life and have seen it all! What irritates me the most is that even though the “rally” is as American as apple pie…..Us locals STILL have to go to work every day! What irritates many of us locals is these BIG horsepower bikes with the 300 millimeter rear tires that look like they are going 150 standing still…..BUT….in reality….We get stuck BEHIND them on the interstate while they are doing a staggering 45 MPH (with 2-5 bikes taking up BOTH lanes) in a 75 MPH!!! I guess “looking” cool means MORE than actually doing the speed limit!
Sorry….That’s my rant for the month!
Sooo lets try and throw the reverse inlet out into the atmosphere is the theory here with this deal, hmmmm. Gimmicks, gimmicks galore. Trying to defy a natural phenomenon that is part of all internal combustion engines. Superflow (and I am sure others) have articles about the advantages of timing the reverse flow to “increase” the power in a engine as Terence Tory brings up in his thoughts on this one. Of course when you take into consideration that any “velocity stack” in the open with the wind rushing by it at speed does the same thing as this, (Ok they got a screen).
Double Bullshit. Stack to short , crap in your engine etc…
Second problem I bet if you ride a bike with those breather bolts after 20 miles they would fill up and start leaking oil.
The entire ‘air-dynamics’ debate/speculation aside (too complex to cover here – eg unless you do a GOOD CFD analysis – you are largely speculating) – if you see what the “atmosphere” looks like that we breath in, in the 21st century, near anything that resembles a city – you would stop breathing immediately.
I would not “run” Velocity Stacks [VS] on anything but a pure show bike – viz it looks ‘cool’ (note: hate that fu**ing word).
The air filters of today have ZERO resemblance to the what was there 50 – 100 YEARS ago.
If you see a bike with a VS then she is in all likelihood one of two extremes – a trailer queen or a drag (strip) queen…
PS – aerodynamics is one of the most complex subjects in mechanical engineering. A race-track/drag-strip is a very controlled environment. A relatively short run (even an endurance race) with engines of a notably limited life. It is risky to blindly apply race dynamics to everyday commuting. Sure you can get “strange” air behaviour to squeeze a bit more out of a motor “On Any Sunday”, but very hot air behaves differently to very cold air and chances are, all you would get in real life is a motor that works well in a narrow window of conditions, the rest of the time it is a dog. In real life, re the air track, the best advice is: KEEP IT SIMPLE SON, just as the best Bourbon, straight and smooth…
These breather bolts beat me. So the “sludge doesn’t go back in”? Where does it go then? Dripping on your engine and from there to the floor? Neat.