Replacing the stock airbox with a UNI Filter
This guide will instruct you on how to replace the stock air intake box on your buggy with a UNI foam filter air intake for better airflow and greater performance!
When changing to a higher airflow intake like a UNI foam filter, you will need to rejet your carburetor to a larger jet size. See the Buggy Parts NW Info Center article on Air Flow and Exhaust and/or article on Rejetting the Carburetor for more information.
This how-to has instructions for both 150cc and 250cc engines.
– 2 Screwdrivers (philips and flathead).
How to install a UNI foam filter air intake
1. Remove all screws to the stock airbox connecting it to the frame of the buggy.
2. Loosen the screw on the clamp connecting the stock airbox to the carburetor intake.
3. Disconnect any breather hoses that run to the airbox and remove stock airbox from the vehicle.
Note: these breather hoses can be zip-tie wrapped to the frame out of the way, but must not be blocked off. You can use a UNI breather filter like this one to prevent dirt and debris from getting into the breather hoses.
4a. For 150cc GY6 engine:
– You should be using a velocity stack (“Redneck Intake”) for this mod.
I. Attach the coupler end of the velocity stack to the air intake of the carburetor and tighten the clamp.
II. Attach the UNI filter to the open end of the velocity stack tube and tighten the clamp screw.
4b. For 250cc engines:
– You can attach the UNI filter directly to the carburetor air intake, or use one of our intake elbows if you are limited in space.
I. Attach the UNI filter to the air intake of the carburetor and tighten the clamp.
5. Remove the red outer sleeve of the UNI filter and use UNI foam filter spray oil to wet the grey inner filter until it is tacky without being soaked or dripping.
6. Replace the red sleeve and repeat the process until the outer sleeve is tacky with oil but not soaked through.
7. UNI filters and sleeves can be cleaned by removing them and using UNI foam filter cleaner spray.
Note: In dusty riding conditions, the red outer sleeve can become caked with dirt. diminishing airflow and performance. Removing the sleeve and shaking it or beating it against a tire can dislodge some of the dirt and restore airflow. Replace the red outer sleeve after this partial cleaning.
Idea: Some people who ride in extremely dusty conditions carry a spare pre-oiled UNI filter in a ziplock bag to swap out when the current one becomes too dirty.
Even better idea: Put an Outerwears pre-filter over the UNI filter to prevent the overwhelming majority of dirt and debris from ever reaching your filter in the first place! Outerwears are water repellent and ideal for riding in dusty, sandy, or muddy conditions where your air filter can quickly cake up full of mud and decrease performance!
When using an Outerwears pre-filter, use the UNI filter oil on the INSIDE of the red UNI cover, not the outside. This will keep the Outerwears pre-filter from gumming up its pores with the oil.