If you have a air leak it will be very near impossible to tune and could burn the top end up. The stator cover, flywheel, and stator, can be pulled and the seal on that side can be sprayed with soap, There is a hose coming from the WAterpump cover, and the crankcase breather hose(coming from white elbow below rear motor mount) can be put into soapy water to check for bubbles. Sent from my iPhone using Tapatalk