Hi Wondering if anyone has had this before. My gl 1500 has 33,000 miles on it I am using rotella 20/40 oil in the summer months when the temp is hot outside. The engine makes a rattling sound when at 3,000 rpms dosen't matter what gear the bike is in only does it on acceleration only when getting off the throttle it stops. Also this only happens when the temp gauge goes over the half way mark ( it is fine before the temp goes up ) It is not overheating and the coolant is full. It is not a lifter or rod knock it does not sound like a wrist pin either. I was going to change the alternator insulator rubbers as i do not know if they are original or not but i cannot see how these would make the sound only when the engine heats up. any help would be greatly appreciated.