Having recently become a Honda guy, I'm looking for any information anyone may have on the early evolution of the Honda HR194 with 4 height levers, sometimes called the "commercial model".
[Linked Image]
Note that the base, handle, and many other features are different from the single height lever HR194.

Here is a sort of generic HR194 commercial (from ebay) viewed from underneath:
[Linked Image]

Note the bar blade, which seems to be fitted to all Honda walk-behind mowers unless they have a U in the type number: HRU has swing back blades, HR has a bar blade. If I'm wrong about that, please tell me.

The mower in the picture has no grass chute, no rear stone shield, and a full-circle part of the base casting that drops down to protect the crankshaft from getting things wound around it. This seems normal for most mowers so far. However, let's look at my similar HR194:

[Linked Image]

It obviously has three major differences from the ebay one: it has a pressed steel grass chute, or "scroll guide" (crudely panel-beaten by me), a top-pivoted rear stone shield suspended from the axles of the back wheels, and a large gap in the crankshaft-protecting circular shield. You can see that this gap in the circular shield is not due to damage, the casting was made that way. I've removed the cover ("roto stop cover lid") that attaches to this gap to take that picture. Assembled it looks like this

[Linked Image]

If you go back to the first picture of the generic ebay HR194 commercial, you can see a couple of the mounting points for the grass chute. They even look as if they have been tapped, so I'm guessing the grass chute has been deleted along the way, as a tenant's improvement. I don't know about the suspended stone shield, but you can see that the axle extensions it mounts on are present, and so are the deep cutouts in the sides of the base to accommodate those extensions. This ebay mower clearly has a full-circle crankshaft-protecting shield as part of the base casting, there isn't a bolt-on section of the shield, so apparently access to the roto stop without removing it was no longer required.

So, there seem to have been running changes in the design of the base of the HR194 commercial. Can anyone tell me anything about this, such as when, why etc.? It may help me to date my mower. The HR194 commercial first went on sale in 1983.