1979 GS750E - Resonant Vibration under load

[BassCliff]

Hi,

A "squeal" could be the tachometer itself. You can disconnect it to test. Then take off the gauges, turn them upside down, and spray your favorite lube (WD40, silicone, 3-n-1 oil, etc) into the cable holes. If that doesn't work, it could be that the mechanism is gummed up and needs to be cleaned really well. In that case, disassemble and clean as necessary. Use a small flat screwdriver and needle nose pliers to carefully pry off the bezel. Then clean up and reassemble.





Clean the bell housing/magnet interface so that the watchspring mechanism is unimpeded.


Thank you for your indulgence,

BassCliff

[gs12tim]

man, what a bowl full of red herrings this one's been.

I took off the front fender, brakes, and front wheel. Removed the speedo hub, and disassembled the circlip etc. Cleaned it all up and regreased. Cleaned up and regreased the axle etc. Put it all back together and checked the torque. As the PO had installed a fork brace, I left the fender off and went for a ride..

Hooray ! no squeal, minimal to no resonance.

Came back to the garage and picked up the front fender. Took a look at the underside of the front edge and yup - polished clean w/ lots of tire residue. My squeal was the sound of the tire deforming under centripetal force and coming into contact with the underside of the front fender. This would explain why the squeal got worse from 60 to 65 to 70 mph. I guess the PO installed the fender incorrectly when he put new tires on it.

Oh well, at least I got a chance (or motivation) to give my new bike the once over. Lubed cables, greased axle & speedo hub, checked carb sync, checked timing, checked coil bolts & tank isolators, found out my headlight bucket was cracked and fixed that... not bad.

And I did get her up to 85 (indicated) and she runs beautifully.

thanks for all the hints & suggestions

Tim

[BassCliff]

Hi,

My squeal was the sound of the tire deforming under centripetal force and coming into contact with the underside of the front fender.

Well, that's a new one on me. Thanks for sharing.



Thank you for your indulgence,

BassCliff