Hello again,
I have worked for a few motorcycle industry manufactures on catalogs and ads for magazines such as American Rider, Drag Specialties, Cycle World... so I am aware that in the industry colors are very critical. American bike part manufactures won't use red since it is seen as the color representing Japanese bikes and vice versa. So I understand you not wanting any orange since that shouts Harley-Davidson. However, I am including a few version using the German colors for your consideration. Mimicking the German flag won't tie into any other bike and may lend itself to the positive perception of German engineering.
Marcelo