As I said long ago, entries and vote. Comments can be made when the voting's over Posting ones bike only to have three of his friends log in and quote so the pics reappear for a page and a half hogging the thread and all this bantering ruin it. I think it's fun but entries, votes and outcome is what it should be and no commenting until the voting's over. JMO nothing more.
That is sensible, and would cut out the spats. But it would also remove virtualy all sense of competition from the thing.
The eventual outcome would be that everyone dutifully posts a pic or two of their latest favourite, then votes for themselves. Okay - that's the extreme scenario, but you would certainly get a massive field with a couple of votes for each and no real sense of a contest.
If you submit a bike for public approval and rating, you should expect to attract criticism as well as plaudits. That way, only bikes whose owners are confident in their offering will get entered - and you don't need any formal pre-qualification nonsense.