Shaking it head

[jamo]

My r65 has just started in the last month or so shaking its head alarmingly.
This happens between 35-45 mph all other speeds it's fine.
I have changed the head bearings and discs last July when I serviced it.
There is no discernable play in either the head or wheel bearings. I have had the wheel balanced and its still shaking.
I am now at a loss. Any one out there able to shed any light on the problem.

[georgesgiralt]

Hello Jamo,
IMHO your set of head bearings have too much play. They need to have a little less play than they have.
It is not uncommon for these bearings to need an adjustment about a 1000 km from new.

[montmil]

New steering head bearings should be checked for correct preload after 100 miles / 160 kilometers and snugged up as needed. The roller bearing and races can move a bit as they find their happy place. With the front wheel off the ground and the wheel pointed straight ahead, a slight nudge on the handlebar should allow the wheel to move to full lock without banging the stops. Falling to the side too quickly and with a sharp impact on the stops indicates loose bearings.

You might also want to check the swing arm pivot bearings for correct preload as well as the rear wheel bearings to confirm they are up to spec.

Let us know what you discover.

[Barry]

Curious that wobble started suddenly. You would think that normal wear mechanisms would not trigger a sudden wobble. Even though you say there is no play maybe a head bearing suddenly seated a fraction. And besides absence of play there should be some preload to provide a damping effect. Definitely check the rear end as well as the front. Could a damper have suddenly failed.

[Tony Smith]

Curious that wobble started suddenly. You would think that normal wear mechanisms would not trigger a sudden wobble. Even though you say there is no play maybe a head bearing suddenly seated a fraction. And besides absence of play there should be some preload to provide a damping effect. Definitely check the rear end as well as the front. Could a damper have suddenly failed.

interestingly in the /7 and earlier the prime cause for the sudden head shake was the absurd top plate used instead of a proper fork top bridge. The failure mode of the plate usually started after the thing had been disturbed for some reason (like changing bearings). If the aluminium crown nut was not tight enough the secondary effect was fretting against the plate, counter intuitively the effect of soft metal fretting against harder metal usually means that the hard metal comes off second best. Before long the fretting sufficiently alters the shape of both the plate and the nut so that the only cure to the wobbles is replacement of both.

Now, the R65 top bridge is a far, far better thing, but I suspect that if not correctly tightened could lead to a similar fault developing.

My advice to the OP is this.

Start at the rear, check wheel bearings and then swingarm bearings. If they check out check front wheel bearings.

Next check the front forks for alignment and for STATIC movement in the head-stem bearings, check the preload whilst you are there.

Then put two of your biggest and heaviest friends on the bike and have them hold the front brake hard on (or put the bike against a stout wall) and lunge the bike forward - you at this point will have the dashboard off and will have your fingers under the top bridge and against the headstem.

If you feel or see any movement in the top bridge, you have found your fault. If you cannot immediately buy a serviceable top bridge, you can have a machine shop insert a sleeve.


And then do not ever leave the top bridge crown nut loose again.

PS, I have never had a case of the wobble in an R65 that wasn't a rear end problem, but i do remember being nearly flicked off my R100 several times before I twigged what the problem was. Which is why to this day my R100 wears a luftmeister top bridge.

[montmil]

Been following member Jamo's identical question over on BMBikes.org.uk and our Airhead friends across the pond respond with the same answers as we do here on our bmwr65.org.

It's kinda like the Borg and their Collective; we are all of the same mind.  

here's the link if you'd like to follow along:

http://www.bmbikes.org.uk/Forum/viewtopic.php?f=15&t=22829

[Barry]

Some of them over on BM Bikes are not familiar with the different arrangement  for the R65 top nut as there is no box spanner involved.  It's an Allen screw.

Jamo,

You did torque that top Allen screw up good and tight  - 60ftlbs. I'm guessing you will have done if you experienced what a bear they are to slacken off in the first place. And you also can't help notice it changes the preload on the bearing. And while we are at it you did have the top yoke clamps slackened off until after the adjustment process was complete.

[Tony Smith]

Been following member Jamo's identical question over on BMBikes.org.uk and our Airhead friends across the pond respond with the same answers as we do here on our bmwr65.org.

You have too much time on your hands Monte  

[marcmax]

I agree with you Tony, Monte has way too much time on his hands. Of course that gives him the opportunity to be the bmwr65.org version of Will Rogers. Sorry Monte, I know he is from the wrong side of the Texican northern border but he was still damn funny.

[montmil]

Youse wise guys... Here's something you may get a chuckle from.

Wedding and baby showers. Those are for the wimmen folk, correct? Always have been and still ought to be. But, no, I have to attend a Baby Shower this weekend. Three days in Austin, Texas.

Unless I'm able to sneak away and visit Revival Cycles down on South Congress, in the shadow of the Tejas Capitol, I gonna be directed by "The Skirts". I'm also told there will be no time available for me to ride my R65 that's stashed in Austin.

Who thought up this so-called trend of man-inclusive chick stuff? It's even worse that the latest fad of these ridiculous choreographed Dancing With the Stars wedding reception events.

Guess I could wish for rain. And beer. Yeah, beer.

[marcmax]

I seem to remember a different attitude from another thread. Let's see, what was that you said.....

Prince nothing. I am King of the castle... and I have the Queen's permission to say so.  

 [smiley=ROTFLMAO.gif]

[montmil]

I seem to remember a different attitude from another thread. Let's see, what was that you said.....

Prince nothing. I am King of the castle... and I have the Queen's permission to say so.  

 [smiley=ROTFLMAO.gif]

Yup. It's that last line that's the clincher.   and I have the Queen's permission to say so.

[jamo]

Thanks for every one that gave advice. Today I have put the advice in to action. Loosened off both fork tube clamp bolts. loosened the yolk top bolt. I marked the adjustment ring to know how far I moved it. Using a pair of pipe grips with no force the ring moved about 3/8" then tightened all bolts the bars still fell to the stop and bounced. I repeated the steps again moving the ring a further 3/8" resistance was encountered.  I tightened every thing again torquing the top bolt to 60 ft lbs the bars moved steadily to the stop with out bouncing.
Took it for  a test ride to 40 mph closed throttle with my hands off the bars letting the speed drop to 25 mph. No shake The problem is cured.
Thanks again every one.

[Lucky_Lou]

I seem to remember a different attitude from another thread. Let's see, what was that you said.....

Prince nothing. I am King of the castle... and I have the Queen's permission to say so.  

 [smiley=ROTFLMAO.gif]

Yup. It's that last line that's the clincher.   and I have the Queen's permission to say so.

Nice quote Monte.. I have to do my Thunderbirds "Parker" impression
Yus Mi Lady. Glad this is sorted I will be visiting my forks soon as I believe the seals are original.
Lou
Lou