I recently acquired this R75/7. The bike runs great, every time I get on it my ride ends up being much longer than I planned, just from enjoyment. The only issue is the tach. The needle would jump around + or - 200 rpm. Now is is beginning to make a lot of noise. When I unhook the cable the noise stops, leading me to believe the tach is gong bad. Don't think I have skill/patience to rebuild it. What is the best option for getting that done. Also will I do any harm in sealing the cable and just riding it without the tach for the time being. Thanks
I would think that a /7 bike should have the electronic tach... there is no drive cable as there was on the /5 models. Which of course leaves only the instrument "head" as the source of the noise.
Back on the RH ignition coil (under the fuel tank), should be a single grass-green wire. That's the wire that sends the ignition pulse to the tach. Unplug that one wire and the tach will take a rest.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I had the same problem on my1975 R75/6. I didn't have the needle jumping problem. The noise did go away when disconnecting the cable. I was able to find a replacement tach, and put it into the gauge cluster. Noise went away. I assume it was something in the tach. I too don't feel competent to try and repair it myself. With the replacement installed, I will eventually send the original tach off for repair.
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