Kamikaze (translated as divine wind)- hey, it sounded cool!  Anyhow, it's actually a DIY air intake that I feel maximizes airflow to the carb similar to a velocity stack.  I did this mod because I noticed that the pod filter has a siginifcant narrowing of the inside rubber, relative to the mounting flange, that sits right over the carb air inlet- at least on mine.  I imagine this narrowing doesn't help air volume and certianly induces some turbulence.  I wanted something better, something to maximize the dimension for airlfow  while minimizing air turbulence.  I feel nothing does this job better by design than the stock snorkel.

Here's what you need:
- Small piece of air filter material (HEPA vacuum cleaner filter, interior HVAC HEPA filter)
- A sturdy container with diameter the size of the ID of the stock air snorkel and a sturdy screw on lid
- Dremel tool
- Razor blade
- Cooking spray

A container like this works great.  


1.  Cut the container so that it fits in the snorkel.
2.  Cut, grind and open up the top of the lid leaving a shoulder
    around the top.
3. Cut a 5" cricle of air filter material and fit it over the container
    opening.
4.  Screw cap on the container.
5.  Use razor blade to trip excess from the bottom of the lid.
6.  Instert the new air filter into the snorkel.
7.  Spray air filter material with a light coat of cooking spray.
8.  Attatch snorkel to carb.
9.  Start bike.
10. Get on bike and ride!













Other options are adding a thin metal screen behind the filter.    

When your filter gets dirty just unscrew the top, replace filter, screw the top back on and trim the excess.    

and,...
any remnants of the Glycerin Suppositories, should only increase combustion!.....

I agree on the metal screen.  I got some a little bit ago as an option.  I'm ditching the polyfill material though.  I was looking at the bottom of the bag and I saw lots of little loose fibers gathered there.  Obvioulsy it's from the collective total of the bulk of polyfill and a small section itself will have very few fibers.   I'm sure that blowing it out before install would remove any loose fibers as well but I'm going a different route now.    

I also found what looks to be a simple drop in filter- it's a HEPA filter for a portable vacuum cleaner.  I'll take pics later and post.  

my thoughts.....  looks nice ...  should work for a while.

But.... as the filter material gets dirty I'm thinking that it will start restricting the flow.    

One of the reasons they use the pleated material in cone filters.  More surface area so that the dirt doesn't clog it as soon.

But... you could try for a while and see .....   then report back...

Thanks for the tip, I might have to look into something of the sort.

Thumper, I'd imagine with that setup you are getting some of the performance similar to this setup.  That's probably why, when all combined, you are popping wheelies so easily.  After riding it this evening I can now see why it would be easy.     

Here are pics of the metal screen that is glued on to the rim.  Obviously this is without the filter material or retainer cap.  



From inside.


   

If you use the auto industry's standard calculation of air required for "nil" vacuum restriction within the air intake system, you should have at least 130% of engine capacity in available air volume between the throttle butterflies and the air filter element.  

I'm not sure if the same applies for motorcycle but I bet it is similarly 130% or around that number.  The Kamikaze tube has a volume of about 30 cubic inches or 75% of engine capacity.  That falls short of the 130% recommended above but is improved over the pod filter.  In addition, it creates a better, more uniform vacuum as compared to a pod filter and it has no narrowing or other obstruction to airflow at the point where the air enters the carb mouth.   My math may be a little rusty but I think I got it right.  

I think my tube needs about 25% more air filter surface area for pulling air in.  I'm working on some ideas to solve this.    

meck wrote on 03/12/09 at 12:28:14:


Meck, I've done about 15 miles with it so far.  There were a few stretches of steady rpm riding in there but most was intentional starting, stopping, hard accels and roll-ons in various gears.  I'm thinking that the combo of free air + vacuum creates a better environment for pulling the gas thru the jets and then emulsifiying the mixture before it enters the cylinder.  Throttle response felt improved.  I think it allows the pilot jet air-correction jet to work better IMO.  I don't know nearly as much about carbs as many folk on here do and I might have some of the stuff mixed up.  I'm sure they will correct me soon enough!

Here's an exerpt from an article about the pilot air correction jet:
"The Pilot Circuit (also called the primary, low speed or idle circuit) consists of a brass fuel jet- called the pilot jet (in the float bowl), the pilot mixture screw (outside of, but adjacent to the float chamber), and the pilot air-correction jet (in perimeter of the “mouth” of the carb). The Pilot circuit delivers it’s air/fuel mixture through a small hole in the floor of the carb outlet, downstream of the throttle plate. It regulates the fuel mixture at idle and small throttle openings, typically under one-quarter throttle. The pilot air correction jet admits air to the pilot system, through a channel above the pilot jet, as a fuel/air ratio modifier and emulsion improver."

I don't know about other's pod filters but mine had a narrowing inside that appeared, when on the carb, would cause some obstruction to the pilot air correction jet circuit.  It may not cover it up but the air certainly had to quickly bend 90 degrees up and again 90 degrees towards the carb.  I think with the pod filter setup I had, I had some rich spots and some lean spots throught the rpm range.  Some of that may have been the jetting/mixture screw setup as well.  Testing yesterday seemed to show a smoothing out of these spots.  I've got a #55 pilot with bleed holes.  My testing included some adjustments with the idle mixture screw.  With the pod filter it idled and ran best 1 full turn out.  With this mod it seems to run best all the way in.  I think the vacuum more efficiently pulls fuel through the pilot jet whereas with the pod filter the vacuum was less so opening it up a turn helped to compensate.  

I'm not saying this is a sure fire improvement for everyone.  I sure made a difference on my bike.  Probably using the K&N and filter in the airbox and and desnorkeling the top probably gets you closer to this setup than the pod filter.  I would love for a few others out there to try it and see how it works for there bikes.  This setup like I've got pictured is pretty sensitive to the material used for filtering.  The material has to be as free flowing as possible due to the narrow inlet area to get the true benefit.  I've tried several things and the best two so far have been 4 washed and dried dryer sheets (the little square ones you throw in the dryer with the wet clothes), and a piece of filter from an indoor HVAC filter rated at 700 (long explanation on the rating).  as far as how long it stays clean? I don't know.    I do know the I live on a long gravel road that gets very dusty.  I've had my pod filter on since October.  I cut it open and removed the material last night.  It looked amazingly clean to me.  I guess if I have to screw on a new 10 cent cloth once every 3-4 months it will be worth it to me.  

BTW, here's the whole carb article.  It's a great read.
http://roadstarclinic.com/content/view/56/96/