Back in August, I wrecked my bike when I was going around a turn. The engine case hit a curb and cracked. Since then I've been in the process of repairing the bike and it's back to ride-able condition -- still have a few minor things to do but that's beside the point. I bought a used engine off eBay, works great. But the registration for the bike still has the old engine number on it. Is this .. significant? Do I need to re-register it with the engine number I put in it? I'm in California. The guy I bought the engine off sent a copy of the title with the engine when I bought it -- it came off a totaled bike from Oregon though the engine number isn't listed on the title at all. I don't think every state does that, just the actual VIN in some cases.