Hi Wayne! On the topic of balance gears, I've just looked at the array of procedures in the K-series manual, and can understand your confusion and frustration.
Perhaps a little explanation on balance-gear concepts will clear some of the fog. In a common reciprocating engine, there are two general 'planes' of motion that need to be suppressed to cut down vibration.
First of all, you have a piston and rod, which is moving up and down in the cylinder. This obviously must be counteracted by SOMETHING in order to supress vibration.
If you spin the crankshaft, with no reciprocating assembly attached, you MAY find (Depending on the engine design) that the crank is balanced by itself... the counterweights counteract the mass of the swinging crank. More often, you'll find that the crank's counterweights are slightly HEAVIER than the throws, because designers have taken into account a certain amount of mass of the attached connecting-rod. Sometimes they even add a little more counterweight mass, to counteract the piston swinging back-and forth. Well-and-good, but...
The piston is just going up-and-down, while the crankshaft counterweights are going in a CIRCLE.
The fact that the piston's reciprocating mass is being worked-against by counterweights that are SPINNING, means that the vertical plane vibrations are being suppressed (in sinusoidal fashion), but the throw's counterweights are shaking the engine side-to-side... SO... it's a matter of evils.
To complicate things even worse, the rod's mass is swinging side-to-side, but also in sinusoidal fashion (it's moving up and down while swinging), but it becomes a rather complicated sum of vectors. To make matters worse, the engine's not shaking in just one plane, it's shaking in an irregular circle, while counterweights are 'trying' to shake it in an opposite, but unequal irregular circle.
So they make these little weights that spin in the exact-opposite direction as the crank, and they contain precision 'weights' which are supposed to be timed in such a fashion as to counteract the worst vibrations by equalling them, but being 180 degrees in the opposite direction... aka., thrust in one vector is being met with equal thrust on an opposite vector.
They had to PICK which vibration to fight, though... and the match of piston, rod, crank, balance gear, and timing were all part of the solution mathematics.
So in engines with balance-weights, it's not unusual to see the weights timed to match the crank throw (up when up, down when down)... just keep in mind that they'll be swinging in the opposite direction. I'm not suprised to see 'em in the 90-degrees out-of-phase orientation... again, they're swinging the opposite way... all depends on the other componentry.
As you can tell by the responses of the bunch... the preferred least-of-all-evils is to remove the weights, and live with a slight buzz from your neck down. I've got a K321 here with an inspection window blasted through the block where the advance weights took their leave of absence... apparently the sum of two equal but opposite vectors exceeded the abilities of the casting which they were employed. I did have a Kawasaki vertical-twin motorcycle with TWO chain-driven counterbalancing shafts... I'll have to admit... they didn't seem to do much good- my feet and hands would buzz for a good long time after just about ANY ride over 10 miles... but in their honor, at least I wasn't taking out the tool kit and tightening down every fastener like the BSA, Triumph and Norton riders did...
