Replace your Chinese Paper Air Filter for 20% to 25% more power.

Last year I got (2) 250 cc (239 cc actually) and (1) 110 cc Chinese Quads. The 110 cc had the regular front air box and 5" x 7" oiled foam air filter. No Problem - was able to get a relatively good combustion mix as evidenced by the spark plug read.

The 250's came with the performance "Round Tapered Paper Cone type filer" - no airbox. No matter what I did, I could NOT get a good burn color on the spark plugs of both ATV's. It was always way too black, even leaning it out to the point that the quads either would not run or start. The Chinese paper cone filter looked fine - hold it up to a light & the light shone right thru it. They both would start right up and seemed to run OK, it was just that the plug was too black (rich).

I suspected the filter wasn't right and last winter built a home made air box with a Fram paper air filter (see my post under "Raceway"). After installing the new air box and filter, neither one would start except with a shot of either - OK, they had been sitting all winter and I had replaced the gas filter & hoses - no big deal, maybe air in the fuel line, etc.

This weekend at 70 degrees and only 3 or 4 days of not being run, neither would start. So, I started messing around with mixtures again and guess what - If I backed out the Idle / low speed mixture screw ¾ of a turn, they both started right up and idled well. (3/4 of a turn RICHER is a LOT !!!! ) So, that Chinese cone type paper air filter was causing a BIG restriction to the inflow of air to the carb.

I went out today to "play" in the sand / gravel pit and WHOW !!! All of a sudden, by the SOP Dynameter (Seat of Pants) it had a good 20% - 25% more torque and horse power. Boy would it climb hills, just spinning the rear wheels like crazy (I also have a 14 tooth front gear with a 50 tooth rear gear - 3.57 ratio). Me at 230#'s, just doing donuts with 3 to 4 complete revolutions !!! (got dizzy after 4 and stopped) (after all, I am 60).

So, If you have a Chinese paper type air filter - GET RID OF IT !!!. Get something made in America and be prepared to richen up the idle / low speed mixture screw. And, make sure that you hold on tight !!!