The Wings are not known for having a quiet transmission, especially the earliest models, and when they have covered a considerable mileage the whining can be quite pronounced.
While I was checking into parts for the 'new' engine I'm building I was really quite shaken by the way Honda had done the gear train on the counter (or lay) shaft.
The second gear and third gear in effect each run on a grooved journal, caused by the cutting of the splines in the shaft.
I had a couple of sets of early gears, most of which were perfect except for a lot of play in bearings of these two gears. The bearing is a pressed-in bronze shell or bush, but this part is not available as a replacement; no separate part number.
Honda did some strange things on these early models, but this is one of the strangest and a rubbish piece of engineering.
But they often seem to eventually realise their mistake and do a rectification job, so I checked into the later parts.
Sure enough, the 78-79 models have a much improved system.
The shafts are the exactly the same but there are now two internally splined bushes (Part #23485-410-003) which slide onto the shaft. The shoulders eliminate two of the splined thrust washers as well.
These now provide a full journal for the gears to rotate on. This is what should have happened right from the start. The difference in the reduction of the amount of slop in the gears is remarkable and should provide a much improved life cycle.
Unfortunately the early gears will not fit onto the bushes, even with the pressed-in bushes removed, so it is necessary to use 78-79 gears. It may be possible to have the early gear bores re-sized to do the job as there is only about one millimetre difference in diameter.