The only quads i have seen with a manual clutch are the sport quads for high speed and racing quads. I have not worked on any new ones so im not sure if they work the same as the older semi automatics. The semi auromatic with manual shift have been around for decades. Just push the foot petal to shift has an automatic centrifical clutch. As. the engine speeds up the centrifical clutch plates move out to grab the drum and you move, then shift to another gear. Not quite as simplistic as the automatics, but give you more control in rocky terrain. Surprized that new ones still have a foot shift i thought most had electric shift. Footshift must be for backup if the electric shift fails.

its the exhaust gasket