The G9 should have been the perfect bike for the careful owner.......they had oil filters everywhere......unfortunately,put one in the hands of the average idiot who owned old bikes in the 60 and 70s,and they suffer.........the meehanite crank didnt resist dirt very well,or reduced oil supply caused by neglected and blocked filters...........so its very common to find cranks ground 060 under ,and more.............IMHO,the other main problem was the forks didnt wear well ,and were easily bent......the stantions apparently a very soft steel.............other problems were cam and tappet wear,IMHO,caused by too strong valve springs........strong springs needed for the 7000 odd revs the horsepower was quoted at...................the B52/GB gear box was ok,but nowhere as good as a AMC box.,and the splined clutch adaptor is often loose on a worn mainshft spline....which means primary chain runout,...same problem as Nortons always had in that era.