I have worked on a friends xtc 700 for a couple of weeks now, jetting seems ok, pipes are properly in place, clutching seems to be good, it might need another helix but that's it. What has got me stumped is the vibration between 50 and 62 mph (80-100 km/h) it comes from the left foot side. The bearing for the drive axle on the speedometerside has been checked by the mechanic that does the bigger jobs (I just tune), so I assume it is ok. I did notice 8 lugs half or fully missing on the left side of the track, oddly that does not add to the vibration when revving on a stand, only at load. Any suggestions?