I am changing out the clutch in my 2003 VTX 1800 and am also thinking of changing the oil brand. I’ve been seeing quite a few people recommending M1 10/40 racing oil, and others say Rotella T4/6. I’m not happy with the amsoil I was using as I had quite a bit of top end noise(more than usual). And want to use a higher Zinc based oil as well. Any thoughts? I appreciate your constructive feedback