Don't know what happened there! I think I was going to say treat your bike to the best synthetic oil, as said in previous posts it is false economy not to. In the grand scheme of things an oil change every 6k is relatively inexpensive unless your clocking up some serious mileage, then you may have to do some serious cost efficient research. Each to their own but I'll stick with my Castrol. The previous owner had used Motul at 2k so it had only been in for 4K when I changed it, the difference with the Castrol is very noticeable.
rather than worry about oil, which by the sounds of it is fine. I'd be looking at your stub axle and suspension linkages. unless you have done them recently could well be shot. should be done every 2 years
