I don't want to piss on your parade, but do you honestly think a judge is going to just throw them all out because he didn't pull you over? You admitted to the officer that you were riding the bike, and that you hit the vehicle. What halfway sane judge wouldn't take that as an admission of guilt? We nail hit-n-run suspects all the time, at their home, days later. There is nothing here that is any different. Whether you showed back up and were a man about it, the fact of the matter is, you initially lied to the officer about it. You're lucky that charge didn't get thrown on there as well. For $450 bucks, I would save yourself the embarrassment in court, and just pay the fines and move on. Again... not trying to be an ass, but I don't see how you could possibly believe that you're not guilty? Based on a technicality? If you wanted to take it to trial, I suppose you might get ONE juror who is on your side, but when it's you, the cop, and the judge, you will never win. The cop is going to say "yeah, I questioned him at his house, his quad was sitting right there, he lied to me, and then showed up 15 minutes later admitting he did it".
You are correct that hearsay is not admissible in court, however an admission to an LEO is admissible in court. You're not going to win a hit and run case. That's a felony around here. I wouldn't run the risk of the judge upping the fines in that courtroom, and just pay the $450 and be done with it...