April: Air Filters & Maintenance
Air filter size: We have thoroughly researched the variety of air filters available for our engines, and have concluded the following. First, get a high quality fabric air filter such as K&N or S&B. The K&N filter offers a better filter element that is easier to clean and maintain, and will outflow the other brands after the first washing or two. They are slightly more expensive, but you get what you pay for. Within the rules of most major sanctioning bodies, (ie no opened ended or velocity stack style filters with inserts, etc), and after countless hours of flowbench testing, we have determined that there is no sense in getting an air filter that is taller than 4 inches in filter element. The standard air filter with dimensions of 3 1/2" diameter by 4" in height is sufficient.We also offer a larger diameter air filter, (4 1/2"d X 4"h), that with a little extra effort will flow slightly better. To see any benefit of the larger diameter filter at all, you need to take a pen knife or small exacto blade to the inside radius of the mounting flange. We can perform this extra work for you if you need, but it is really pretty simple and straight forward. Also, we recommend the straight filter flange as apposed to the popular 20* angled flange filters that some shops and large mail order houses sell. While the angled filter "can" flow equal to the straight filter, if it is not mounted in the proper direction / orientation, then it actually hurts the airflow significantly. For this reason, we only recommend the straight flange filters.
Air filter maintenance: It is imperative that you use a clean and properly oiled air filter and or pre-filter every time that your kart enters the track. Cleaning: Cleaning the air filter properly requires just a bit of time and care to protect your valuable investment and keep it operating at it's peak. Remove your air filter from your engine, being careful not to allow any dirt or contaminants to fall into the carburetor air horn. After removing the air filter, use a short piece of duct tape to cover the air filter adapter to protect it from anything falling inside. Gently brush any loose dirt from the outside of the air filter with a soft bristle brush or soft tooth brush. Next, completely saturate the filter from the inside out with cool tap water. Spray liberally, a degreaser such as Simple Green, to the outside of the filter and let set for 15 minutes (not allowing it to dry). Wash / rinse the filter from the inside out. A garden hose with low pressure works great, or even better is a hose attatchment at your kitchen sink. Rinse thoroughly, repeating as needed, thoroughly rinsing the filter and allow to air dry overnight. Never use compressed air to dry the filter as it can damage the filter element, (or fabric inside the filter,) allowing dirt to enter the engine. If you need to dry the filter more quickly, you may use a common hair drier on a low heat and air setting. When dry, spray the exterior of the filter with a high quality fabric filter oil such as PJ-1 or K&N fabric filter oil. Completely cover the filter with an even coat. The filter is now ready to install.
If you use a foam pre-filter, you may wish to clean and oil it similarly. Please be sure to use an appropriate oil designed for foam filter material. Ther IS a difference! For convenience and frugality, you can also use automatic transmision fluid as your foam air filter oil. Just keep a bit in a small container such as a coffee can, and be sure to wring the foam pre-filter out thoroughly before putting it over your fabric air filter. Having extra filters to replace during a racing event is a great idea. You can pre-oil the filters and store them in a ziplock bag to keep them in a clean and safe environment. This also saves a step at the track and prevents dirt contamination by trying to do your filter oiling at the track. NEVER spray filter oil directly on the engine or while the filter is still attatched to the engine.