...
a mell of a hess.
here is another potential hell of a mess:
you can see that both the primary gear and that driving the balancer shaft were not tight. This is one of the best kept secrets at Yamaha concerning this engine group. It happens because the the package - the two gears plus the spacer and the two sheetmetal spring retainers for the balancer gear - is undersized and this primarily because the two sheetmetal discs get compressed. When the package is too small, the big nut on the crank locks up against the shoulder that can be seen. No amount of tightening then tightens the package and the 6mm woodruff key in the crank must bear the entire torque. Sooner or later it shears off and the balance and crank meet - just once - and the both are finished for good.
This happens much more frequently than Yamaha is wont to admit.
Keep and eye on this and on the gear on the balancer itself were similar stuff can happen.