Hi Just bought an 85 vf750c Magna - learned to ride on it as a teenager and always wanted one. Under strain there is a very loud rattle knock type of sound from the bottom rear of the engine area - almost sounds like it´s coming from the pipes. Not the tranny or shaft cause it keeps going for a bit If I stop and rev - but only does it after riding for a bit - then it goes away. I have heard of the inner pipe weld going and causing a loud rattle - is there anything else in that area of the bike that could cause this noise? I am a novice mechanic - but learning