Shampoo Air Box how to: intake silencer and air jetting

Ok loud intake haters,

Here's how the box is made.

What u need!

Tools:scissors, hole saw, hack saw or pipe cutter

1. Shampoo bottle cleaned out well at least 3in Diameter. Less diameter doesn't work as well idk why

2. Pantyhose

3. Few hose clamps

4. A foot of 3/4in irrigation tubing

***5. Some rigid wall metal tubing or pipe, size depends on your hoses

So what ya gotta do?

Select hoses. The combo hose setup I use here is specifically for phbg, cuz the sump pump flex hose hits it perfect. Otherwise you could just use a radiator hose that fits your carb. In this situation, I'm using a 1.5in ID 2in OD radiator hose to join to the bottle. The flex hose is about 1.25in OD when stretched.

1. First cut the bottle all the way around so the top can slip over the bottom section. You'll have to cut a notch in the bottom section to allow it to shrink when the top part goes over it in a slipfit. Clean it again.

2. Next, get your hole saw and pick a size of hole that is smaller than the OD of your radiator hose. My hole is 1.75in and the hose is 2in OD. When you squeeze the hose into the hole it will be mostly airtight due to the interference fit.

3. Then! ******

Find a piece of pipe that just fits into the larger radiator pipe, that will be inside the airbox with stretched pantyhose around it, and hose clamped or cable tied to the sandwiched pipe~>hose~>pantyhose~>clamp

Doesn't matter what metal you use, pvc might work too but I never tried it.

4. Squeeze the filter/hose assembly into the bottom of the airbox from inside. Spit and pliers helps, sounds like a hot date!

5. If you're phbg'in it, find that flex hose and cut a length that'll work for ya, I go as short as possible, but up to about a foot. Find another metal tubing spacer that fits tightly inside the flexy tube. Then screw the flexy guy with the metal tubing in it up into the radiator hose on the bottom of the airbox. Once it's in, hose lamp it into position on the outer radiator hose.

6. Now cut your intake ports in the top section. I usually cut a very small circle in the bottle then cut an X to about 3/4in. The tubing will slip in easily and stick in due to interference fit.

7. Cut the intake tubes from 3/4in plastic irrigation tubing. I do length anywhere from 1/2in to 2.75in.

You can have anywhere from 2-4 tubes, you can experiment with tubes of different lengths, plugging some holes with rubber cork, some long tubes, some short. The more tubes the more air, but also more loudness.

I cut a X into the outer end, and use pliers to bend them out into a flange, so they don't fall into the box. You might have to jet down a touch with this mod if you're at 4 short tubes and it's still too rich.

But then it's very easy to change your jetting as you can pull a tube entirely out of you need more air.

It's all experimentation.

8. Assemble the top and bottom sections, and wrap tape around to seal. Electrical tape works great for this.

That's pretty much it. Changing airflow for your jetting is so easy once you have a setup dialed in.

Feeling a lil lean? Add a longer tube or add a cork to one of the ports.

Feeling rich boggy? Add some shorter tubes or pull them all out.

No intake tubes will still silence the intake, but not that well. The tubes are the key to this setup.

The dome top really does a lot of silencing due to its reflection of soundeaves back into the intake.

NOTES:

1.don't leave much extra pantyhose on the edges as it can flip up into the box when you're running and block air.

2. Make sure that pantyhose is streched tight and clamped hard. If it comes off it's got a one way ticket into your carb and engine.

3. As for the top of the bottle, if you decide to make that a port as well, it allows like 3x the air as the side ports. It can make you run lean, I usually just keep the cap on these days.

Ok that's it. It's super simple but I don't think I ever made such an in depth instruction guide.

Good luck

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Re: Shampoo Air Box how to: intake silencer and air jetting

nice writeup

never saw you mention the metal ring on the inside, thats huge.

always wanted to make me one but i just cant handle that much junk hanging off my bikes. 100 miles on my polini this weekend had my ears ringing though... maybe its time to change my mind.

Re: Shampoo Air Box how to: intake silencer and air jetting

As far as number of ports,

This 50cc very ported reeded av7 only requires 2 ports. Same with my 50cc very fucking ported derbi with a 21mm phbg.

If you're running 65cc+, do 4 ports and you can always plug one if it's too much.

Re: Shampoo Air Box how to: intake silencer and air jetting

2 more notes.

I usually use some electrical wire or string and tape that to the bottles cap or tie it around the cap, then secure the air box to something on the frame so it doesn't flop around be like scooters ball sac.

As well, orientation of the box is easy, it will turn on the bottom rubber hose to adjust what direction you want air intake and the sound to come from. Very helpful in rain.

Just make sure you have all connections tight and if you're clamping onto a hose make sure it's in the space where the metal inside spacer is. That makes it secure and mostly airtight.

The flex tube can be flattened when you clamp it to the phbg. Just flatten it with the clamp once on and then trim the excess and reclamp so you're sure it's on that lil threaded input to the phbg

Re: Shampoo Air Box how to: intake silencer and air jetting

Yeah my ears never ring after riding. The only loud sound is out the exhaust.

> Graham Motzing Wrote:

> -------------------------------------------------------

> nice writeup

>

> never saw you mention the metal ring on the inside, thats huge.

>

> always wanted to make me one but i just cant handle that much junk

> hanging off my bikes. 100 miles on my polini this weekend had my ears

> ringing though... maybe its time to change my mind.

Re: Shampoo Air Box how to: intake silencer and air jetting

The guide we needed, gonna throw one on my TM24

Re: Shampoo Air Box how to: intake silencer and air jetting

One more thing.

Your engine needs a lot less air than you think. Especially 50cc.

If you're running anything less than a 15phbg, you only really need 2 ports.

Even my ripper ripper 50cc hobbit only has 2 tubes and I'm getting to 11k + I think. it's all about jetting to the box and engine together.

They work in tandem.

Lastly on piston port engines.

This airbox works great, just have to rejet a bit, it's worth it in the end for eliminating that soaked leg bullshit. All the backwash that made you stink is now trapped in the airbox, and is sucked back in.

That's how you can run a bit rich on these setups w/piston port so you have to rejet.

This airbox shines with reeds. Best thing ever to ride along at a very low volume when running a 24mm oko. Ya night and day in sound

Re: Shampoo Air Box how to: intake silencer and air jetting

Various applications,

Flex hose can be pulled towards the frame with a spring if the hose is floppy

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Re: Shampoo Air Box how to: intake silencer and air jetting

These boxes can all be painted with spray paint or covered in a sock or cut very accurately if you care about that shit.

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Re: Shampoo Air Box how to: intake silencer and air jetting

One other tuning trick.

On my 70cc + ripper builds, the fastest bikes I have, I often leave one port wide open, then run 2 standard tubes, and plug the 4th port. I think the small amount of unmetered air really helps keep everything consistent and with no noticeable loss in power.

Re: Shampoo Air Box how to: intake silencer and air jetting

Once using this setup, I always just jet the carb to the box first, I'll have a tube setting that I like, then try to get it dialed in.

Once you're pretty close dialing your carb jetting, that's when adjusting lengths and amount of tubes can show immediate results, very quick adjustments more lean or more rich.

Re: Shampoo Air Box how to: intake silencer and air jetting

Thanks for the write up Jbotty! The pics are RaD

Re: Shampoo Air Box how to: intake silencer and air jetting

> JBOT Admin Wrote:

> -------------------------------------------------------

> One more thing.

>

> Your engine needs a lot less air than you think. Especially 50cc.

>

Yeah this is really something that you just can't jam through people's thick fuckin heads.

The engine is only pulling full draw for like 2 millionths of a second, at WOT, full blast. The rest of the time, the mass of air flowing into the mouth of the carb is some kind of a sinusoidal-lookin wave, going negative sometimes (the gas on your foot spitty out part). Putting an airbox on there- even a stock dinky one- traps all that air coming back and jams it back in the engine when the carb sucks again. The best airboxes that i've ever looked at/studied/simulated are four stroke dirtbikes that are basically working like a reverse expansion chamber creating awesome supercharge pressures.

The real fucker with this is that when your carb presure goes positive or real close to positive, all the fuel that is being drawn through the jets looses suction and drops back out of all those little metering circuits which means when the engine sucks again it has to pull it back up. This is also part of why a misfiring or a poorly running engine sometimes needs huge jetting to run right. Back in the good ol' days when people posted lots of info on this forum, there was a thread every week with someone running like a 120 something jet in their PHBG/Puch polini setup because something was fucked up.

You look at anyone from formula 1 to 125cc kart guys who know how to build engines and they all have a lot of effort put into the airbox, sometimes more than the exhaust.

Problem is... similar to the Walter Kaaden quote about pipes: (from memory)

'you know a pipe is designed correctly when its impossible to mount, hits everything, and burns the rider's leg'

Re: Shampoo Air Box how to: intake silencer and air jetting

thanks for posting the design Jbot. so a tuned intake should help out your gas mileage seeing as your keeping the blowback in the system. how does the length of the intake tract affect performance? I see you you use about a foot of tubing before the bottle. does this create more velocity as opposed to putting the bottle directly on the carb?

awesome info in this thread. i never put much thought into the intake just slapped on a pod filter. thinking of the intake like an expansion chamber seems like there's alot of performance if not efficiency being left on the table.

Re: Shampoo Air Box how to: intake silencer and air jetting

I try to run as short as possible.

Using a radiator hose you can mount it into the carb within inches.

I've just had to mount some of the French style bikes with longer hoses. They're all rippers and don't care about the hose.

Can't speak to mpg, I do know that my setups run very consistently regardless of weather or temp. The large volume of air trapped in the assembly evens out the pressures and just makes shit smooth.

It's so cool to adjust jetting by precisely and minutely changing air flow.

NOTE: Don't assume your jetting will go up or down with the addition of the air box. I've seen some setups that require fatter jetting with the box vs no box. Some need leaner. It all depends on the design and hose length and amount/length of ports. Jet with the box on and disregard what your jetting was before with only a pod filter (edited)

Re: Shampoo Air Box how to: intake silencer and air jetting

One thing to remember,

When you adjust air flow, it affects the WHOLE RANGE.

So if you're lean on the main, and you swap to longer tubes or plug a port, your main might be perfect then, but then your needle and air/fuel screw might need to be adjusted to a more lean position because of the change in overall air flow.

Re: Shampoo Air Box how to: intake silencer and air jetting

> JBOT Admin Wrote:

> -------------------------------------------------------

> One thing to remember,

>

> When you adjust air flow, it affects the WHOLE RANGE.

>

> So if you're lean on the main, and you swap to longer tubes or plug a

> port, your main might be perfect then, but then your needle and air/fuel

> screw might need to be adjusted to a more lean position because of the

> change in overall air flow.

any cool tips on what tubing for mikuni tm? 45mm ID

Re: Shampoo Air Box how to: intake silencer and air jetting

Hose you mean.

Inch conversion is 1.77 so get a hose that has 1 3/4 ID.

Not rocket science

Re: Shampoo Air Box how to: intake silencer and air jetting

There's an airbox thread I started about a year ago with some good info on sizing in it. I think seem to remember that you're shooting for an airbox volume about 10 to 20 times your cylinder volume? So a liter shampoo bottle is perfect. Someone even went into the math on noise attenuation in regards to the size and length of the feeder tubes

Re: Shampoo Air Box how to: intake silencer and air jetting

This box has proven itself on every bike I have. The design is flawless.

It's never failed me. Such a cool lil thing

Re: Shampoo Air Box how to: intake silencer and air jetting

Brandon Weiss (Detective brandon to you) /

I gotta go hit up my local hair salon for empties, wanna try this

Re: Shampoo Air Box how to: intake silencer and air jetting

If you find a broken washing machine, this rubber flex tube is inside from the tub to the pump, and it's pretty bitchin.

I added an adaptor to the phbg to fit the larger hose.

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(edited)

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Re: Shampoo Air Box how to: intake silencer and air jetting

" I do know that my setups run very consistently regardless of weather or temp. The large volume of air trapped in the assembly evens out the pressures and just makes shit smooth."

feckin right!!!! ive been say'in this for years.

I had a A55 tomos that would wheeli, go 40mph all day, and still get 113 mpg. with only an aftermarket pipe, modded air-box, re-jet, and slightly increased sprocket ratio, and the main jet was only like 5 sizes bigger than stock.

"It's so cool to adjust jetting by precisely and minutely changing air flow."

my other modded stock A55 w/ airbox would get up to 45mph with a different pipe and steeper gearing. i used to tune this Streetmate with by taping over holes i drilled in the airbox. more tape when its cold out, less tape when its hot out. super useful in RVA with spring/fall 40F temperature swings.

then i did the same thing with another A55 except i modded the stock pipe.

then i moved the setup onto a 505D with similar results.

now im designing an air-box for my Morini M01. wanna keep it quiet when i put a pipe on it. (edited)

Re: Shampoo Air Box how to: intake silencer and air jetting

Heck yeah, thanks for the tips!

Re: Shampoo Air Box how to: intake silencer and air jetting

Ya know the vent thing on your Weber grill? I’ve done that with a disk of plastic on opened up stock airboxes before. Easier than tape, also can use as choke if for whatever your choke ain’t working.

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