Motorcycle Repair: Speedometer

Question
The speedometer on a 1970 Yamaha GS6/7 was not working. Got a new cable and it works now but backwards 80-0 instead of 0-80.
Any suggestions? Thanks, Terry

Answer
Terry,

Odd speedo problem for sure. I would suggest checking
that the worm gear in the wheel is working properly
and going the right direction. Other than that
there is a possibility someone installed the wrong gears.

Any other problem would have to be in the speedo itself.
When magnetism is lost the speedo may go up and down
or look like it is dropping in speed. This can only be
fixed by a calibration unit or magnetizer.

I worked on Yamahas for many years and I never saw that happen.
I did have one engine that ran backwards!

Luck to you,

WS
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