Bouncing on front forks?

[8ninety8]

I'm about to replace fork seals and will likely take things apart. Last time I disassembled the front end, (about 1990) new bearings, springs, yokes, brace, etc., I vaguely remember at some point of re-assembly grabing the front brake and bouncing the the forks vigorously up and down before tightening something.

I've gone through many threads in various info links and old BMWMOA tech articles and I can't find where I read this (bouncing the fork) and what and why exactly was I doing before a final snugging up of something. Maybe it's not important, but I'd like to remember exactly what to do before taking it apart, again.

I've never had any problem with this bike, (R90S) no wobble at any speed, no stiction, can't induce wobble, always snaps back when provoked, not upset by bumps when laid over, no play in bearings, forks drop correctly side to side, should I just forget about taking it apart beyond installing new seals? Any advice is welcome.

[20774]

My recollection is that the bouncing is done to let the front end find its proper place as you tighten things in steps. You should start at the top and work down, tightening each area as you do down. Lower yoke pinch bolts, fender brace/brake caliper hold down, large axle nut, axle pinch bolt.

Another approach would be to remove the top caps and the fork springs. Then, with the front end off the ground, perform the same gradual tightening process, but at each stage, ensure that the sliders can easily be lifted by hand. You'll need the axle installed. If at any stage, stiction shows up, investigate before you move on. Then reinstall the springs and caps.

I probably remember this from Snowbum at http://bmwmotorcycletech.info/frontforks.htm

[shire2000]

I have always bounced the front end to realign things after tearing it apart.
Assemble everything but do not tighten anything beyond finger tight.
1. Install the front wheel and snug up the axle, and finger tighten the pinch bolts. Torque up the top yoke. Install brake components and make certain they work. If bike has disk brakes, torque the caliper mounts at this time. Bounce front end, getting good movement.
2. Torque the bottom yoke and the front axle and then pinch bolts.
3. Lastly bounce again and torque the fork brace.

Lastly, go over every bolt with the torque wrench just to make sure. Also, if the bike has disk brakes, I will loosen the mounting bolts and retorque them, just to ensure that they are aligned correctly. I get a little anal with front ends. If something comes loose, it is usually at the most inopportune time and either in the middle of nowhere or the middle of traffic. Neither one is a good thing.

That's the procedure that I have sed for a long time. Hasn't failed me yet.

:ca