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Question on initial steering head bearing install

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Mark Malin
(@18720)
Posts: 7
Active Member Customer Registered
Topic starter
 

Hi, all

I have an 88 R100RS and am replacing the steering head bearings and fork seals.  The bike is currently sitting with the forks/wheels/brakes/handlebars/etc. off (obviously) and the steering head removed.  I have replaced the bearing races in the steering head (upper and lower) and have the lower bearing on the steering head "tree" (the tube that attaches to the lower triple clamp.  I'm going to use a Toaster Tan upper clamp FWIW.  I need to work on the forks now, but want to at least initially install the steering head "tree".  I realize that I don't seat the steering head bearing pressure until the forks, wheels, etc are on (if I understand correctly) but want to pack the bearings and slide the mechanism into the bike's frame, put the top bearing in place, install the cap (cover) and put the tensioning adjuster nut on to seat the bearings such that I can leave it like this until I get ready to do the forks.  How tight should I tighten that adjuster nut?  And I assume it's OK to let the assembly sit like this without the upper triple clamp installed as I work on the forks, right?  

PS - if anyone is in the Madison, WI area and is experienced with doing the fork alignment and such and feels like helping...beer and food will happily be provided!

 

Mark

 
Posted : 11/24/2023 12:14
Brad Wernecke
(@14295)
Posts: 10
Active Member
 

Mark I can not figure out how to contact you!  So come and meet other WI airheads for a beer on Saturday, December 2 around noon, at the Great Dane Brewery on Jupiter Rd in Madison WI.  I would be more than happy to come by and give you a hand as I too live here in Mad-town!  Contact your Air-Marshal for more details and/or my contact info.  Brad Wernecke

 
Posted : 11/27/2023 09:33
Mark Malin reacted
Mark Malin
(@18720)
Posts: 7
Active Member Customer Registered
Topic starter
 

Posted by: @14295

Mark I can not figure out how to contact you!  So come and meet other WI airheads for a beer on Saturday, December 2 around noon, at the Great Dane Brewery on Jupiter Rd in Madison WI.  I would be more than happy to come by and give you a hand as I too live here in Mad-town!  Contact your Air-Marshal for more details and/or my contact info.  Brad Wernecke

 

Hi, Brad!  I'm trying to figure out how to reach you, but also can't seem to figure out how to contact you. I'll try to be at the December  2'nd event.  Meanwhile, if you'd be up for helping, that would be fantastic!  We just need to figure out how to contact each other.  

 

 
Posted : 11/27/2023 13:42
Richard Whatley
(@wobbly)
Posts: 2499
Member
 

• Take your time selecting a long-term water-resistant grease for the head post bearings. Apply it liberally and wipe off the excess after installation is complete. These bearings need the grease for water protection, not lubrication.

• The bearing "nut" under the yoke (aka "crown") has a specified torque of 29 ft-lbs. This torque will draw-up and fully seat both the new bearings. Unlike other motorcycles, the Airhead runs the head post with a pre-load torque. I usually install the yoke at this time. This allows you to re-mount the gauge cluster and keep it out of harm's way. 

• Use that same water-resistant grease to repack all the springs and sliding bits that make up the steering damper adjustment block on the underside of the triple tree. You'll be glad you did.

• Before you install it... exercise the hydraulic steering damper unit by pushing/pulling the piston through a full stroke several times. Fit a new hydraulic damper if there are any issues with the unit. 

• Before installing the tubes, clamp the axle end of the leg in a vise and spin the tubes in the fork legs. This is great way to check for bent stanchions, which will show up as wobbling at the top of the tube.

• Before installation is a very good time to turn each of the stanchion assys upside-down and pump out all the old fork oil. A good brand of 7W fork oil (250cc per) will restore the original ride and steering control. 

• If you'll wipe the tubes with an oily rag, a very, very thin coat of oil is all it should take to seat the tubes all the way into the triple tree. Do not tighten the triple tree pinch bolts until the top caps are installed and torqued. 

• When complete, with the steering damper set to "0" position, the forks should flop back and forth with very nearly zero resistance. There should not be any "tight spots", ratcheting or other hindrances when rolling the head post bearings from lock to lock. 

 

If you have the front end that far apart, you may also enjoy reading THIS.

 

Hope this helps.

This post was modified 3 months ago 2 times by Richard Whatley
This post was modified 2 months ago by Richard Whatley

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

 
Posted : 12/05/2023 14:36
Mark Malin
(@18720)
Posts: 7
Active Member Customer Registered
Topic starter
 

Thanks for the info.  One question - you mention the bearing nut having a torque spec.  I’m wondering since it is designed to be tightened using the “hook spanned” (we are talking about the nut with the notched in it), how can I torque it to spec?  And then do I back it off for and tighten it with the hook spanned to set the bearing preload?

 
Posted : 12/05/2023 14:56
Brad Wernecke
(@14295)
Posts: 10
Active Member
 

Richard and Mark,   Please note: Mark has a 1988 R100RS which is a newer mono-lever model.  His bike will have very different parts and specs than those given above, which seem to apply to the older dual shock models.  Brad

 

 
Posted : 12/11/2023 15:26
Steven Rankin
(@14724)
Posts: 145
Estimable Member
 

Just a note, while the bearings in the steering head don't spin like regular wheel bearings, they do still in fact need lubrication.  The grease provides this as well as a tiny bit of cushioning against the pounding force the bearings are subjected to.  So not just to keep water out.  St.

Beware! I do not suffer fools gladly! St.

 
Posted : 12/12/2023 06:26
David Elkow
(@4949)
Posts: 279
Reputable Member
 

Oy, … I am confused by this discussion. My bike is a ‘78, but here the ‘88 looks very similar. There are 2 nuts at the top of the steering tube. One is more like a ring with slots in the edge, to be turned with the hooked spanner in the tool kit. This nut is under the top plate. It adjusts the preload force on the steering bearings. For my bike the preload torque is 350Ncm +/- 20, which translates to 29 to 33 inch pounds. Most folks do it by feel, verified by riding. THEN, there is a big CAP NUT on top of the top plate. This nut locks the adjustment in place, and secures the top plate. It gets the big torque figure of 120 NM or 87 ft lbs.

 
Posted : 12/13/2023 18:57
Brad Wernecke
(@14295)
Posts: 10
Active Member
 

Thanks Dave, you hit the nail on the head!  Thanks for simplifying this.  It is the same set up for both bikes, and your procedure apply to both models.  Mark has this part down pat, and is now onto the Randy Glass Fork Alignment procedure.  

 

 
Posted : 12/15/2023 08:48
David Elkow
(@4949)
Posts: 279
Reputable Member
 

Final thought.  Verifying the steering bearing preload by riding.  If the preload is too little (loose), going 30 to 40 mph in 3rd gear, loosen your grip on the bars and cut the throttle (no brakes) - the front end will want to wobble. If the preload is too much (over tightened) the bike will want to hunt and wander strangely at low speeds. 

 
Posted : 12/20/2023 19:00
Mark Malin reacted

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