Here are the photos I promised, but I got no joy from reinstalling the cable.
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But here is the rub -- if I move the front wheel backwards, it causes the speedo cable to turn. If, however, does not turn if I turn the wheel in the forwards direction.
It seems that my worst fear has been confirmed -- it is a problem with the gearset in the front wheel, not the cable or the speedometer itself.
The part is as follows:
BOX ASSY., SPEEDOMETER GEAR (Honda Motorcycle Code 1111335)
However, it is "unobtanium" as far as I can find. Looks like I'm headed to the motorcycle salvage yard, soon.
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Lee