<img src="http://upload.wikimedia.org/wikipedia/commons/b/b8/Opposite_piston_engine_anim.gif"><ul><li><a href="http://en.wikipedia.org/wiki/Image:Opposite_piston_engine_anim.gif">http://en.wikipedia.org/wiki/Image:Opposite_piston_engine_anim.gif</a</li></ul>

<center><img src="http://www.petealbrecht.com/blog/deltic2.jpg"></center><p>Diesel, 2-stroke, 18-cylinders. Saw use in fast patrol boats and railways. Applying full throttle would take a couple minutes of run-up.

with one of their race bikes. It's now in the museum, but they brought it out to a historic event and one of the DKW Club members helped push-start it - apparently it was ear-splitting. It may have included a supercharger as many of the factory race bikes did.
Cheers!

That Deltic is one cool motor, worth reading up on!

<img src="http://upload.wikimedia.org/wikipedia/commons/6/60/Napier_deltic_animation.gif">

Used both on high speed naval ships, and British Locomotives.

Has a distinctive and interesting exhaust 'note' when running hard.<ul><li><a href="http://en.wikipedia.org/wiki/Delta_engine">Wiki entry</a></li></ul>

Cook Inertial Propulsion engine<ul><li><a href="http://www.forceborne.com/FBW/simplified_explanation.htm">http://www.forceborne.com/FBW/simplified_explanation.htm</a</li></ul>

looks like oiling that sucker would be a nightmare...