The difference between auto and motorcycle lenses is that the auto lens/reflector typically has a shade over the bulb that is not used in motorcycle lenses due to vibration concerns.

Richard Atwell covers it well (with pictures!)

http://www.ratwell.com/technical/BoschH4.html

> On Jun 30, 2015, at 5:22 PM, Jeff Palmer <jpalmer@MYMTS.NET> wrote:
> 
> Hi everyone. I've had Bosch H4 headlights in my van forever. Model 0301600107. I see in my bus depot kit that they use 0301600118 labelled Motorcycle. Which is correct for my 85?
> 
> Thanks
> Jeff 
> 
> Sent from my iPhone

It's really easy to fall into the trap of believing what we do is more important than what we are.
-- Fred Rogers