1937 or Mid-'38 Gear Cover

 This cover was in poor shape.  Note the bronze rivets. (I think these rivets held a type of throw-out bearing oiler?)
 It has a unique cast-in flat boss for a vent fitting (above the kicker)
 New bushings and honed for fitment(by yours truly)
 DC Welding repaired and welded the damaged kicker boss, and McFarland Machine bored the cover for the new bushings. 
 You can see(photo above) where the rivets held some type of accessory - no longer needed.
Palmer's "How To Restore Your Harley-Davidson" is a very important book.