I was getting alot of back fire in the carb. I've cleaned the OEM filter and hand wiped the air box before only to make more HP but the carb was still back firing. This time I took the air box and snorkel completely off the carb, cleaned them with an air compressor and nozzel then replaced the OEM oiled air filter w/ a K&N air filter. Put it all back together and WALLA!, no more back fire. I can even ride wheelies w/ my 3,000 lb. WARN winch mounted on the front. I've never been able to do that before now. The backfire was caused by the lack of air flow through the snorkel which is mounted beside the radiator cap under the front-side of the handlebars.