• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Steering Stem Removal

jschara

New member
I'm tryin to get to my front fork bearings on my 1979 R65. Have removed the upper triple clamp but can't seem to ge t the stem to go down. From videos I have seen a good wack should do it. No such luck so far. Any suggestion? Heat?

Thanks, Jim
 

Attachments

  • 0-47.jpeg
    0-47.jpeg
    48.5 KB · Views: 168
  • 0-48.jpeg
    0-48.jpeg
    47.5 KB · Views: 169
Front Fork Stem

Excuse my ignorance but from your photo, it appears that the fork tubes are still attached to the lower triple tree and they're resting on a block of wood. IOW, it appears there's still force preventing the lower triple tree from dropping.

RPGR90s
 
That's correct. The forks are still attach to the lower triple clamp so that I won't have to re-aline them if I only have to clean the bearings. I drop the wood block a few inches when pounding on the stem so that they will drop. Good eye.
 
The weight of the forks puts a sideways load on the stem, making it resist the "good whack" on top. A pointed tip Sharpie will help mark the fork alignment and depth into the lower tree for reassembly.
 
You were right on BoxerBruce. Once I removed the forks the assembly droped with a hit of the hammer. It looked horrible in there, but once I cleaned it up, the races felt perfectly smooth. Both top and bottom. I'm thinking, just clean and repack the bearings and reassemble. Any thoughts?
 

Attachments

  • 0-50.jpeg
    0-50.jpeg
    41.9 KB · Views: 93
What do you mean by "the races felt perfectly smooth?" Based on your photo, it looks like fretting (false brinelling) has set in. This is the characteristic failure mode of rolling element bearings in situations where the bearing is stationary and exposed to vibration. In motorcycle steering head bearings, much of the life of the bearing is spent with the motorcycle going straight rather than turning. You need turning (rotation) of the bearing in order to wipe a film of lube between the rollers and races which prevents the microscopic contact of the roller metal and race metal which leads to fretting.
 
I would replace the bearings. You are there, they look like they may be worn in. You are in this far, why not change them.
 
What do you mean by "the races felt perfectly smooth?" Based on your photo, it looks like fretting (false brinelling) has set in. This is the characteristic failure mode of rolling element bearings in situations where the bearing is stationary and exposed to vibration. In motorcycle steering head bearings, much of the life of the bearing is spent with the motorcycle going straight rather than turning. You need turning (rotation) of the bearing in order to wipe a film of lube between the rollers and races which prevents the microscopic contact of the roller metal and race metal which leads to fretting.

+1, the bearing pictured is shot as a steering head bearing.
 
Replace

I knew a fellow who greased the old bearings and reinstalled them.

Three months later he replaced them.

If it were me, I would replace the bearings and races both. St.
 
If you do replace the races, make very sure the bottom one is completely seated before going for a ride. It's a very strange feeling after you hit the first good bump and some up/down play suddenly appears in the steering stem. Or so I'm told. :) And I have a lower race removal tool if you'd like to buy or borrow it.
 
If you do replace the races, make very sure the bottom one is completely seated before going for a ride. It's a very strange feeling after you hit the first good bump and some up/down play suddenly appears in the steering stem. Or so I'm told. :) And I have a lower race removal tool if you'd like to buy or borrow it.

Certainly make sure the races are bottomed out. The lower race is recessed so I use one of the old races on top of the new race to ensure that it is bottomed out. This will capture the old race but a sharp whack on the side with a chisel will pop it out.
 
Back
Top