I love it. Your use of a 1/35th scale german motorcyle is excellent. The skin tones/highlights could be better, but very creative. I am going to try several similar conversions.
This is sooo much better than the commercially available Ork bikes. If this was a kit, I would buy several! It has a few weaknesses, as have been pointed out, but it really makes me grin widely. Waaaaargh! the Orks!!