1990 BMW K75 Headlight Shake

[mdk_mdk]

Hello, new MotoBricker here, I picked up a 1990 K75 off of Cape Cod and just got it back on the road (See attached JPEG). Great to be back on a Brick, I had a blue 1986 K75C back when I was a lad, loved that bike, put 65K miles on it before I sold it when kids and a house came. (See my avatar picture)

The K75 from Cape Cod is a just a K75, no real fairing, only has a small headlight housing and instrument panel. The issue I have is the headlight shakes when riding, friends say they can see it shake a lot in their mirrors when I'm behind them. I took the headlight off and the 4 mounting screws are tight but I'm wondering if the bushings need to be replaced. (See part #5 in the attached RealOEM PNG diagram below). The bushings don't look dry rotted or worn but they do move around a bit. I did some searching but all the posts related to headlight shaking were for the K75S, not the K75.

Does anyone know if there's another way of tightening the headlight housing or determining if the bushings need replacing before I put out $56 for new bushings?

[Laitch]

Welcome!

I've got a '95 K75 with the same setup. It doesn't wobble severely. The illumination is good. There is some vibration of the headlight, especially on gravel roads or if the front wheel needs better balancing, but I've decided to be unbothered by it and consider it a form of safety conspicuity. :giggles  We don't have the K75S stuff-the-monkey option with our models.


If you install new bushings, please post the results. I get most of my OEM parts from Max BMW online.

[The Mighty Gryphon]

Legal Disclaimer:  I don't own this particular model and because I am basing my response on studying the provided parts list illustration I am probably talking out of my butt.

#6 in the illustration appears to run through the rubber bushing.  If the rubber has shrunk through age, there may be insufficient compression for the bushing to grip the parts it isolates.  I would suggest adding a washer or two under the flange of part #6 to increase the compression on the bushing.

[mdk_mdk]

Interesting...I was thinking the same thing!
I'll have to find a washer that's the right size (ID & OD), I'll let you know how it works.

[The Mighty Gryphon]

 A hard washer may not be necessary.  A piece of rubber gasket material could be cut into washers to be put under the flange. 

[mdk_mdk]

Good idea, I have some bulk gasket material that I can try.

[The Mighty Gryphon]

Keep us posted.

[Motorhobo]

That's a great looking bike -- graphite black is my favorite brick color. I painted mine after 15 years and considerable abuse and one of these days I'm going to have it professionally done -- same color.

I just checked my bike which is the same as yours -- if I put my hand on the lens and move the headlight around, movement is transferred to the blinker assembly in concert. So headlight, headlight mount and blinker assembly are effectively a single piece when it's all assembled properly. If your headlight moves independently of the headlight mounting assembly or the left/right blinker assembly then something's not right.

I've had some issues with that hardware that holds the entire headlight assembly together. I can't remember the details but I remember that I had trouble lining up the mounting screws with the threaded piece that was supposed to accommodate them. So the screws popped right out as soon I started riding.

Did you disassemble the whole headlight assembly? I remember it being a PITA to get back together.

[mdk_mdk]

I found some thick, 1" OD, 0.5" ID washers in my basement hardware store that cleared the inner pin and installed them between the large bolt washer and the rubber grommet. Worked well, the headlight assembly still floats but does not have as much movement as before. Thanks for all your help!

[The Mighty Gryphon]

Great!  Thanks for the update.

[blackie1]

thx for the kick up the ass MDK
i have had my K75 for a year now and had just gotten use to the "they all do that" headlight/instrument panel shake

found a couple of washers in my shed and 15 x mins later all firmed up.

my bike is an RT with the fairing removed so i was able just to remove the headlight, extract bolt "2" in your diagram above and slip a washer, the same size as you used, over that bolt and re installed.

very easy job for me as i have no fairing to contend with but even so I would recommend the rest of you groovers and "shakers" harden up a bit

[Laitch]

. .  .  I am probably talking out of my butt.

[beemuker]

We don't have the K75S stuff-the-monkey option with our models.

I have a K75s and I have the headlight wobble. Kind sir, what monkey are you referring to that could use a good stuffing?

[The Mighty Gryphon]

Ah, Naked Lunch, "that moment when you actually see what's on your fork".  It was the bible in my circle of friends in the late 60's.  We used to greet each other with "you got any replicas in there?".  I was always surprised at how many really hip people didn't know that the name Steely Dan was lifted from the chapter "AJ's Annual Party". 

It's scary how much of what I see today looks like stuff from that book.  I think it's now the San Fransisco city charter. 

[mdk_mdk]

Glad it worked for you also @blackie1. You can order the rubber bushings for about $60 but since they weren't falling apart or dry rotted, seemed like a waste. I think as someone said the bushings shrink over time and just need a little more pressure to expand and hold the plastic housing.

thx for the kick up the ass MDK
i have had my K75 for a year now and had just gotten use to the "they all do that" headlight/instrument panel shake

found a couple of washers in my shed and 15 x mins later all firmed up.

my bike is an RT with the fairing removed so i was able just to remove the headlight, extract bolt "2" in your diagram above and slip a washer, the same size as you used, over that bolt and re installed.

very easy job for me as i have no fairing to contend with but even so I would recommend the rest of you groovers and "shakers" harden up a bit