Wobble Baby Wobble

[JPSpen]

Fairing was off when I got it.. I saw no need to put it back on..

I already have two fully faired bikes...And the GS with the popeshield..

I'm getting close to wrapping up this motorcycle trailer project.. Then I'll have a look at the back end.. I agree on the rear end causing apparent front end issues...
I'll be checking and resetting the swing arm and all the bearings..

John

[JPSpen]

Update.. It finally cooled off enough for me to get a good look at the R65.

OMG !!!  The swingarm moves back and forth almost 3/8 of an inch...

Anybody know what size the socket is for the swingarm.. I thought I had one but none of mine will fit...

Thanks

John

[Barry]

You need a thin wall 27mm socket or a standard socket can be modified to fit. As well as reducing the wall thickness so that the socket fits into the frame aperture, grind or turn the end face down to remove the lead in chamfers.  This ensures the socket get a good purchase on the thin lock nuts.

[JPSpen]

So, While several folks guessed the problem might be the swingarm.. Nobody would ever believe this unless they saw it with their own eyes...

There was a 10mm nut in the grease between the adjuster and the wall of the swingarm keeping the adjuster from being tightned far enough to load the bearings...

BMW of OKC last had this apart for a clutch... So you know the mechanic just said F'it....

This is why I work on my own stuff...Jeez...

Does the swingarm just center up between the two sides ?  or is the spacing greater on one side  ?

Thanks

John

[montmil]

... Does the swingarm just center up between the two sides ?  or is the spacing greater on one side  ? John

Gaps between swing arm and chassis should be equal. Drill bit shanks can be useful measuring "sticks".

You will need to use a pair of ViseGrips or similar to hold the 27mm socket while the correct size Allen wrench can pass through the socket and snug up the pivot pins. Little bit on this side... little it on the other... ad infinitum.

Once you're equidistant with the gaps, start snugging up the 27mm nut. This may require a few attempts. Use the Allen to keep the pins from moving.

Monte
Still fighting the remnants of a two and a half week bout with pneumonia

[JPSpen]

The wobble is gone.. Bike rides as it should now...Completely different from the way it was... Even when it didn't start to oscillate, It was still pretty squirrelly at times.. All that is gone now...
Pegged the speedo....
What a fun little bike...

John

[Semper Gumby]

Hi John,

You are not going to like this much but...

With the Vetter fairing (and side panniers?) on, you have overloaded the bike.  You can help things by going down Monte's list but the simple fact is that the front forks are not stiff enough for the added weight of the Vetter on the front end.

I went through all of this on my R65 10 (?) years ago.  I tried everything: Telex front fork brace, 100/90H18 rear tire monted on the front, setting the pre-load on the rear swing arm bearings to the maximum torque allowed.  Nothing worked.  My bike would start to wobble near 65 mph.  I was going to send my rear swing arm to SanJose BMW for bracing when I gave up.

So what cured this?  You have two choices.  Remove the Vetter or bolt a K100 front end on the front of the bike.  It has larger diameter front forks and 18" rim that is 2.5 inches wide.  The bearing numbers are the same for the R65 and the K100.  Try to get a solid mount K100 top tripple tree.  The early ones had rubber anti-vibration handlebar mounts that make braking "interesting".

The R65 was designed to be a Nekked bike (yes I know there were few European R65RTs.)

FWIW - With the 1988 K100 front end is rock solid at 90 mph (downhill with a tail wind) and the steering is greatly improved at speeds above 50 mph.  

There are two types of K100 front end: standard and "S" sport forks.  I didn't plan it this way but I ended up with the Sport forks.  The "S" is stamped on the top of the forks on the nut.

Good luck.

PS - My old R65 front end is about to go on a BSA Hornet Cafe bike.

[Semper Gumby]

Ah you removed the fairing - Good for you!  

I use a 4mm allen in accross gap between the the frame and the swing arm to center the swing arm in the frame.  I push it side to side until the amount of play is the same in each gap.

I hate to say it, but I wonder what the BMW mechanic did to the clutch?  What year is this bike?  (fingers crossed)  

[JPSpen]

The clutch and seals were done late 2010.. I picked up the bike early 2011 and returned it to stock...Rode it a couple of times and then replaced the tires.. After the tires it was still funky and that's when I discovered the swingarm wasn't right....

She's good now...I've put more miles on her this week than the last year and a half...

John