rotoral

Hello everyone - I need help! I converted my Hirobo 315B from Nitro to Electric and that came out great. If the main rotor is in perfect track, I get a nasty vibration. De-track the blades and she runs smooth. Anyone ever seen this before and what size main blades should this model run?? And finally, the plastic tail rotor grips seem to have so much slop around the bearings and I have seen the tail blades actually spin out of track. Have their been any upgrades or modifications that can help eliminate this? Yes, I have replaced the tail grips. Always appreciate your time and advise..