CURED! The Curse of the Buzzing Mirrors ....
Posted: Fri May 04, 2007 8:39 pm
From the "I should have thought of that sooner" department (cross-filed under the "Why didn't BMW think of this" department):
I've owned my R for just over four years now, and like everyone else, I've learned to live with the mirrors that vibrate at certain rpm's. I've read the posts concerning this (every few months someone new will join the board, who will have just acquired the bike, and will ask, "Is this normal?") and I've even seen a few suggestions for a cure. CycleRob posted a "someday in the future I'm gonna ..." post a while back where he wistfully envisions boring a hole in the underside of each mirror, then filling the cavity with an assortment of nuts and bolts in a glue stew concoction, so that when the glue hardens the mirror body will be substantially heavier. More mass = less vibrating, at least in theory.
I'd been thinking for a long while about something simpler, when it hit me. What do the Evolution-engined Harleys (not the counter-balanced Twin Cam 88's) do to quell their shaking? Well, they isolate the engine from the frame by virute of rubberized motor mounts. Well, Duh! Could it really be that easy? What would I use to rubber mount my mirrors? I'd been toying around with the idea of possibly snipping some small pieces of old bicycle inner tube when I got the light bulb flash in my head. So this is what I did:
Went down to the local home improvement store, meandered over to the plumbing stuff, and came away with several different sized rubber O-rings.
This is the first package I tried, and it fit perfectly:
I'm sure you metric folks can find an equivalent. Now here's what you do - remove each mirror, insert an O-ring at the base of the stalk, above the threads, and another at the top of the nut that screws on to the threaded portion of the stalk. Voila! Now, go take a ride, and notice that the dreaded buzzing - particularly in the infamous 4-5,000 rpm range - is gone! Now my mirrors act like every other bike I've owned (the numbers are legion), and I can actually see what's behind me. Calm and clear (is that a copper behind me?) up to the most ridiculous rpm levels. I'm talking above 6 grand, where I visit only rarely when revving the beast through the gears. Oh, just a hint of vibes sneak in as the revs rise, especially on the right side for some reason, but WOW what an improvement. Try it, you'll like it!
Now if you've never removed your mirrors, be advised of one little problem I had. As I stated above, the mirrors have a threaded section at the base of the stalk. They are held onto the bar by a specialized nut that screws on to the threaded section from below. Which means you've got to get under the handlebar, and using an allen wrench (there should be one in your toolkit that fits), turn that nut until it comes off (careful not to drop that nut and lose it!). The left mirror went fine, but on the right side, that nut is partially obscured by the switchgear housing, so I had to fiddle with it quite a bit before I could get the wrench on it. When trying to re-mount the mirror, access was so cramped that I got the nut on kinda sideways, and ... promptly proceeded to strip the threads on the mirror stalk. Major Bummer! After checking Ebay for some replacement mirrors, I decided to try filing the knackered threads, and sure enough, that did the trick. Didn't take much, just ran a file along the threads and cleaned up the gnarled threads a bit, and when I tested the nut on the threads off the bike, it went on just fine. So I attacked it again ON the bike, this time using my fingers to get the nut started straight, and in a moment I knew I had it. Couldn't wait to go for a ride and try out my solution, which I now know works like a charm!
I've owned my R for just over four years now, and like everyone else, I've learned to live with the mirrors that vibrate at certain rpm's. I've read the posts concerning this (every few months someone new will join the board, who will have just acquired the bike, and will ask, "Is this normal?") and I've even seen a few suggestions for a cure. CycleRob posted a "someday in the future I'm gonna ..." post a while back where he wistfully envisions boring a hole in the underside of each mirror, then filling the cavity with an assortment of nuts and bolts in a glue stew concoction, so that when the glue hardens the mirror body will be substantially heavier. More mass = less vibrating, at least in theory.
I'd been thinking for a long while about something simpler, when it hit me. What do the Evolution-engined Harleys (not the counter-balanced Twin Cam 88's) do to quell their shaking? Well, they isolate the engine from the frame by virute of rubberized motor mounts. Well, Duh! Could it really be that easy? What would I use to rubber mount my mirrors? I'd been toying around with the idea of possibly snipping some small pieces of old bicycle inner tube when I got the light bulb flash in my head. So this is what I did:
Went down to the local home improvement store, meandered over to the plumbing stuff, and came away with several different sized rubber O-rings.
This is the first package I tried, and it fit perfectly:
I'm sure you metric folks can find an equivalent. Now here's what you do - remove each mirror, insert an O-ring at the base of the stalk, above the threads, and another at the top of the nut that screws on to the threaded portion of the stalk. Voila! Now, go take a ride, and notice that the dreaded buzzing - particularly in the infamous 4-5,000 rpm range - is gone! Now my mirrors act like every other bike I've owned (the numbers are legion), and I can actually see what's behind me. Calm and clear (is that a copper behind me?) up to the most ridiculous rpm levels. I'm talking above 6 grand, where I visit only rarely when revving the beast through the gears. Oh, just a hint of vibes sneak in as the revs rise, especially on the right side for some reason, but WOW what an improvement. Try it, you'll like it!
Now if you've never removed your mirrors, be advised of one little problem I had. As I stated above, the mirrors have a threaded section at the base of the stalk. They are held onto the bar by a specialized nut that screws on to the threaded section from below. Which means you've got to get under the handlebar, and using an allen wrench (there should be one in your toolkit that fits), turn that nut until it comes off (careful not to drop that nut and lose it!). The left mirror went fine, but on the right side, that nut is partially obscured by the switchgear housing, so I had to fiddle with it quite a bit before I could get the wrench on it. When trying to re-mount the mirror, access was so cramped that I got the nut on kinda sideways, and ... promptly proceeded to strip the threads on the mirror stalk. Major Bummer! After checking Ebay for some replacement mirrors, I decided to try filing the knackered threads, and sure enough, that did the trick. Didn't take much, just ran a file along the threads and cleaned up the gnarled threads a bit, and when I tested the nut on the threads off the bike, it went on just fine. So I attacked it again ON the bike, this time using my fingers to get the nut started straight, and in a moment I knew I had it. Couldn't wait to go for a ride and try out my solution, which I now know works like a charm!
