Usually on the frame rail just below the engine. Depending on the yr. they are being made alot less accessable. Most of my bikes are right in the footpeg area or up around the steering neck.
Lower frame rail, left side, in front of the foot peg area, near the front wheel. Easy to see by looking through the left wheel well and down. If you turn the wheels to the left the rear of the LF tire could almost hit it. :cheers2: