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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Brahma on February 27, 2020, 08:58:03 PM
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Having owned my 1985 K100RT for 35 years, I am no stranger to the vibrations of the exhaust guard. As my bike has aged, the flimsy captured nut retainers have broken bit by bit, and sounds loud enough to wake the dead have been experienced throughout the decades. I would adopt some "fix" and it might last a season, only to have to try again some months later. Short of getting the OEM repair kit introduced some years later by drilling and inserting threaded pop rivets where the captured nut retainers are- a kit that took me fifteen years to find, I finally was given what I thought was a skeptical solution by my older brother.
At seemingly any hardware store, GE Clear Silicone can be found in tube form for under $10. With the guard removed, and no matter how little of the captured nut retainers are left on the exhaust, flood the area liberally with the silicone- including the nuts. Likewise, on the underside of the guard, run a bead where the guard sits atop the captured nut retainers. Do this for every attachment point. Allow the silicone to "skin" up for no more than ten minutes, then mount the guard and secure. Allow to cure for at least 24 hours without running the bike.
What happens is not only is there a bit of extra adhesion of the guard to the exhaust given by the silicone, but it also must fill any void that will cause vibration! What I was skeptical about actually works! The silicone can take the heat- there is no smoking or odor, and the bike is quieter than it has been in years! I don't know what it will look like when it comes time to ever remove the guard, but the vibrations are fixed!
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Update- it's now November and the exhaust guard still remains vibration-free, which in my experience is not only a world-record, but truly phenomenal. I urge everyone experiencing this awful nuisance to give this a try- it is definitely working for me...
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Thanks for the update with the long-term success of your remedy, Brahma.
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Mine starts to sing right at 3600 RPM, It reminds me to stop being lazy and bump the shifter. Seriously thanks for the tip the singing gets on my nerves sometimes.
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Thanks for the tip! I've installed the OEM repair kit and have also done the other trick with fiberglass insulation jammed between the muffler and heat shield but it still buzzes. I'll give this a shot, hopefully within the week.
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Mine starts to sing right at 3600 RPM, It reminds me to stop being lazy and bump the shifter. Seriously thanks for the tip the singing gets on my nerves sometimes.
It tells me to twist the throttle!
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The silicone trick didn't seem to work in my case . . . but my current thought is that an internal baffle or pipe is loose.
EDIT: Well, it might have worked after all. After the silicone treatment there was still a loud 'brraappp' vibration sound around 3,000 RPM near the front of the exhaust guard, around the front bolt mount. I noted that section had a fairly low contour crown and would have a wave vibration around 3K. So I used a block of wood and a big hammer to create a higher crown and that seemed to fix the problem.