did my 10k maint. couple of days ago and got to put 150 miles on today. ive been using mobil1 20-50 vtwin and royal purple 75-90 in the primary and trans. switched to amsoil to give it a try and dam im impressed ! my primary is totally quiet now. no difference in trans shifting but less primary noise. i still have about 1200 miles before the motor oil needs changed and i have the 20-50 vtwin amsoil sitting on the bench.if it quiets the sewing machine down alittle quess i'll be staying with amsoil.