Velocity Stacks???

[Ric]

Just curious to see if anyone has thought to put OR successfully put velocity stacks in between their pods and carbs. It seems like a plausible idea once the stock airbox is removed, more so on twin-cylinder bikes. And since motorcycle engines as a whole make their power at high rpm compared to a car engine, it'd be possible to tune the incoming air pulse to offer a tunnel-ram effect, getting more out of a pod filter setup.

I have a plethora of other weird thoughts/ideas that pop in my head from time to time, just go easy on me - I'm still learning what hot rod tricks work and what don't on bikes(the 4-bbl on a Vmax would've never worked out).

 

[tkent02]

Decent pods have little velocity stacks built in.

 

[Ric]

Okay, glad to know that! Is that all a bike needs if one decides to go that route? Or am I thinking more like a tuned port/tunnel ram intake and mistaking it for a velocity stack?

 

[Steve]

Keep in mind that anything "tuned" is tuned for one particular engine speed.

Also keep in mind that if it's tuned at one speed, it will be DE-tuned at another speed (when the pulses are out of phase).

You might notice that a "tunnel ram" manifold draws air from a plenum of a specific size for that engine. Not sure there is enough room on your bike (what bike is it, by the way?) to do that setup properly. You might also notice that you usually find a tunnel ram on a race car, more than likely a drag race car. They tend to spend most of their time (what little there is of it) ONLY in the upper extreme of their RPM range. They spend very little time at part-throttle, cruising down the road at 60 mph or accelerating carefully out of a turn in the hills. Think about how your bike is REALLY going to be operated.

Believe it or not, the factory engineers put more than just a few minutes of thought and design into the bike, and what came on the bike actually works quite well.

.

 

[gs11ezrydr]

Just look inside a stock air box plenum and you will see rubber velocity stacks/carb boots inside the plenum attached to the rear of the carbs. Defiantly helps CV carbs I have left my plenum on with the rubber velocity/boot stacks inside and removed the air filter case and attached a long oval K+N filter to the large round hole that attaches the air box to the plenum. No side drafts, Rain water etc. One large filter and better cross distribution between the carbs No pod woes either lol. Stage 3 jet kit installed it flows that well and no loss in throttle response off idle or dead spots during roll ons. Stacks at the rear of pods who knows might be on to something, Right length and spacing ???

 

[Ric]

(what bike is it, by the way?)

Believe it or not, it's a little GS 300. It does good for what it is, but even as good as it does now it could use all the help it can get carting my 280-lb carcass around.

You make a most excellent point about such a narrow operating range. I think I'll ditch this thought now, because this thing actually pulls good down low. Don't wanna take that away.

 

[chuck hahn]

You need something like these. Measure the OD of the airbox side of the carbs and order appropriate size. Ebay search MOTORCYCLE VELOCITY STACKS and youll get a bunch of sellections.

http://www.ebay.com/itm/39mm-39-mm-...550-/230997908570?hash=item35c88c5c5a&vxp=mtr

 

[Ric]

That's kinda an issue - I don't have the free time to measure the inlet horn at moment, and I can't fi d the dimension online(believe me, I've googled like mad). Does anyone know it right off the top of their head? Stock Mikuni BS30SS.

 

[JJ]

You need something like these. Measure the OD of the airbox side of the carbs and order appropriate size. Ebay search MOTORCYCLE VELOCITY STACKS and youll get a bunch of sellections.

http://www.ebay.com/itm/39mm-39-mm-...550-/230997908570?hash=item35c88c5c5a&vxp=mtr

Who in their right mind would want to run those on the street? All they are good for is keeping rocks and pebbles out of your engine.

 

[8ball]

That's kinda an issue - I don't have the free time to measure the inlet horn. Does anyone know it right off the top of their head? Stock Mikuni BS30SS.

I'm sorry, but, WHAT?! You don't have enough time to loosen a clamp, push back an air box boot a couple mm's and put a set of calipers on it, but you will have enough time to mess with your jetting and needle heights to get your A/F mixture good enough that the thing will run anywhere near properly? There is no magic formula for jetting for mods. I guarantee you will have the carbs on and off 3 or 4 times....at a minimum....to get it right.

And i agree with JJ about the wisdom of v-stack....even with screens....on a street bike. And for a track bike, I dang sure wouldn't be using a cheap universal eBay set. I'd want some with a bit of R&D behind them.

 

[Ric]

8ball, I get it. I know what you're saying. Look back at my edit, I tried to clear that up very shortly after. If it helps more, I'm on a big job repaving a segment of road in the Great Smoky Mtns National Park. That's gonna take up my time till the end of the month at least. I asked if anyone knows that diameter for that reason as well as because I have no calipers, and it'd take too long to pull all the stuff off just to pull a tape and then put it all back on. This bike is my way to work for now, so I can't get too involved with it duri g the workweek... and what little time I have after work I spend eating dinner and getting ready for bed, along with a few minutes to love on my family. With that dimension, I can order pods and a few different size jets to cover the ballpark, and then on a weekend I can take the time to swap and tune.

Admittedly, I've had those carbs off enough cleaning them in the past that I SHOULD HAVE taken a measurement. But I didn't. I didn't think I'd be going with pods till just recently.

 

[JJ]

Admittedly, I've had those carbs off enough cleaning them in the past that I SHOULD HAVE taken a measurement. But I didn't. I didn't think I'd be going with pods till just recently.

Ummmm, if you don't have enough spare time to measure your carbs, you definitely don't have the time required to dial them in with pods.

 

[60ratrod]

But but.... what about the cool factor? Actually, i agree with the majority here. If it runs fine now, and is your only transportation, leave it be. Since you are working something that i can only assume is an hourly wage job to support your loved ones, just wait until you have something else that you use as a daily driver and then tinker with this. That way you aren't out wages due to being stuck on the side of the road. Believe me when I say i know your predicament. I lost my family due to working nights and being gone in the navy. Having just enough time for your basic needs and their love is top priority over working on something that isn't broken

 

[Agemax]

Who in their right mind would want to run those on the street? All they are good for is keeping rocks and pebbles out of your engine.

I run 29mm smoothies on my 1000 with stacks and filter socks, on the street with no problems

 

[JJ]

I run 29mm smoothies on my 1000 with stacks and filter socks, on the street with no problems

I'm sure your filter socks offer much finer filtration than the mesh screens on the stacks in the eBay listing.

 

[Joe H]

Are you running these;

http://www.ebay.com/itm/Ramair-Moto...-Double-Trumpets-Velocity-Stack-/351209511379

 

[Agemax]

Are you running these;

http://www.ebay.com/itm/Ramair-Moto...-Double-Trumpets-Velocity-Stack-/351209511379

yes, i am.

 

[Ric]

But but.... what about the cool factor? Actually, i agree with the majority here. If it runs fine now, and is your only transportation, leave it be. Since you are working something that i can only assume is an hourly wage job to support your loved ones, just wait until you have something else that you use as a daily driver and then tinker with this. That way you aren't out wages due to being stuck on the side of the road. Believe me when I say i know your predicament. I lost my family due to working nights and being gone in the navy. Having just enough time for your basic needs and their love is top priority over working on something that isn't broken

Brother from an old Army sergeant, thank you for your services to help me sleep more soundly at night - sounds like it cost you a lot and I really hate that it happened to you!

I'll definitely keep it as is till I have everything to make the change, to include time. It needs an oil change, valve adjustment, and fork seals anyway, so a good weekend left alone with it will have it freshened up real nice. If I do err, I'll make sure to err on the rich side as well. That way I can still get to work for the week, and readjust the next weekend. It ain't my first rodeo, just my first CV carb.

When I was 18, I swapped a piston in my XT500 in an hour, and never pulled the engine out of the frame(okay, I did spin it 90? to pull the head and jug, but technically...).

 

[Joe H]

yes, i am.

Agemax, do you like them? Been thinking of trying some out on a project I have. They look like they would work as good as any other foam filter for dirt.

 

[Agemax]

Agemax, do you like them? Been thinking of trying some out on a project I have. They look like they would work as good as any other foam filter for dirt.

They seem to work rather well as far as filters go, they do filter well and offer no restriction to the air flow in the stacks.