Never did find my camera cord just took the card out and put it in the computer. Here is a picture of the bud air filter. I just took a racket ball container that has a screw on lid. I attached the lid to the carb and cut the container to the right size, by cutting the bottom off. the beer can is a perfect fit did not have to use any apoxy or anything. Fome in the biddle with oil on it. Oh ya a little silicone blue RTV stuff for seal lid on carb.
I made one of these out of pepsi cans (as im too young to buy beer :cry.
I made a motorized bike for a college engineering project, so I had to write a lot of information about each and every bit, also made this diagram of the can air filter. Might be of use if you want to make one.
The stock air filters on the Happy time carbs dont allow much air to flow. If you are after performance then this is one of the most basic modifications. There are several different materials you could use as the filter element. Each has its different advantages, depending on where you ride depends on what level of filtration you need.
The main two types of filter elements:
Pleated paper filter elements are very commonly used for engine air cleaners, because they are very cost efficient and can easily be replaced. Once they clog up you can just throw it away and replace it with a new sheet.
Polyurethane foam elements are used in some aftermarket replacement off road air filters. By adding a little bit of oil to the foam it is possible to enhance the dirt collecting properties of the filter. Foam is especially suited to catching large particles such as dust and sand; it also allows very unrestricted air flow. A disadvantage is that it isn't very good at stopping small particles of pollution.
If you want enhanced filtration with out effecting air flow much, then a thin nylon mesh material, like womens tights can be used as a screen on top of the sponge element.
The next thing you need to think about is how the filter is going to be housed. The filter needs to be protected from heat, and also needs to be in a sturdy housing because the carburettor vibrates a lot from the engine.
There are many different shapes you could use when designing the housing, but compactness is usually a priority.
This cylinder air filter is designed to take up very little space. There are cone shaped varieties and other dome shapes too. (A coke can or beer can can be perfectly modified for this shape.)
This shape is ideal for a car but where space is limited isn't really suitable. It has the advantage of having a high flow of air 'rammed' into the intake because the panel is facing the oncoming air flow as the bike is moving.
This is similar to the existing Air filter, it is made for a Chainsaw engine. It has. A low air flow rate because
of the small air intake holes.
A velocity stack is a generally cylindrical tube with a radiused inlet end device, (looks like a horn shape). Which is used between the air filter and the carb intake. It is designed to:
1. Allow smooth and even entry of air into the intake duct with the flow stream adhering to the boundary layer that adheres the pipe walls.
2. Modify the dynamic tuning range of the intake tract by functioning as a small reverse megaphone which can extend the duration of pulses within the tract.
3. Alter the dynamic tuning speed (dynamic engine compression) if it includes longer or shorter lengths thereby changing the tuned length to a lower or higher rpm.
Basically the shape of the stack speeds up and smooths the airflow as it enters the carburettor, a perfectly tuned velocity stack can increase the horsepower of the engine.
This is my home made air filter, it is made from a coke can and filled with a slightly less porous sponge element to the stock air filter, but has much more holes in it to increase air flow, I have put some oil on the sponge, and used a screen made from a pair of tights! Works great, and you get a great sense of satisfaction too. I cut the original air filter box to give me a mounting plate to the inlet on the carb, this was then bolted to the can which fits almost perfectly. The concave indent at the bottom of the can was popped out by using a hammer carefully, this left me with a dome shape on top of the can.
First I drilled out the holes where the screws would go through to hold the filter in place to the inlet, then drilled a further ten holes in the dome for air flow.
Give it a go, its not difficult, and its not hard to make an improvement on the existing filter. Make sure you post some pics of your DIY filters to inspire others. Hope this all helps!