I have a '01 250 4x4 that I recently got running again. When riding, the transmission slips for a second (hesitates, shudders) before fully engaging. Its more noticeable in higher gears and when shifting at higher RPM. I've also noticed slippage when turning hard and applying throttle. I'm not familiar with this quads clutch system. Could this be a centrifugal clutch issue? I just changed the oil to a motorcycle grade oil but not Suzuki brand oil. Not sure if that could be causing this?