BMW G650X Challenge Thread Index

Discussion in 'Thumpers' started by GB, Apr 24, 2008.

  1. leafman60

    leafman60 Long timer

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    Also requested-

    From original post 8518 XCo thread

    After 24,000 miles, I have finally replaced my worn steering bearings on my XCountry.

    I’ve read several other accounts of notchy bearings after low mileage. Reasons have been given that allege no or little grease from the factory and/or poor bearing pre-load due to the original set-up or lack of owner maintenance.

    These are tapered roller bearings and the problem is that the rollers can wear into both their inner and outer races and create detent pockets that grab the rollers and try to hold the wheel in the straight-ahead position.<o

    My inner and outer races from the lower bearing that supports most of the bike loading-

    [​IMG]

    [​IMG]

    Examining my bearings shows grease from the factory. My lower bearing after removal and its inner race after removing the roller cage-

    [​IMG]

    [​IMG]

    Based on this info, I assume my bearings ran loose without proper pre-load and the rollers vibrated around on races creating those scars.


    is is not a step by step guide for doing the replacement but I have, a few tips on removing these bearings.

    The X series bikes are designed different from the GS cousins. They have an all-aluminum triple clamp/steering stem assembly. The stem fits into a clamped receiver in the top bracket and an aluminum stem bolt threads down through the top bracket into the stem. Tightening this bolt pre-loads the bearings. When proper pre-load is obtained, the fork tube and center stem clamps are tightened to hold that pre-load. There are no castle ring nuts or any of that stuff as found on other bikes.

    View of top bracket and center stem bolt. The center stem clamp bolt can also be seen.

    [​IMG]

    Once you have removed the wheel and for tubes, simply loosen the center stem clamp, remove the center stem bolt and drop the stem and lower bracket out. You do not have to remove the handlebars and all the instrument/headlamp assemblies.

    Removing the lower bearing from the aluminum steering stem is the fun part. I used a Dremel tool and cut-off wheel to cut the roller cage and then used a screwdriver to pry it apart.

    [​IMG]

    Once some of the rollers fall out, the cage and remaining rollers fall off and leave only the inner race that must be slipped off its stem boss.

    Follow the factory manual and in spite of anything you see for other bikes (with steel stems), heat the entire lower bracket and stem to 180-200 degrees F. You can use a home oven and the silver bracket paint will not be damaged with this temperature.

    Then, clamp the stem assembly in a protected vise. Having a heat gun or hair dryer to keep heat on the race is also a good idea.

    [​IMG]

    With a suitable tool, you can then drive the inner race off its boss. It will slide under impact without too much trouble. You drive against the little ridge around the race that retains the rollers.

    [​IMG]

    Once off the boss, I cut the race through with my Dremel and wedged-in a chisel to spread the race and allow it to slip over the top boss that’s not as tight of a fit as the bottom.

    [​IMG]

    Use the old split race upside-down as a driving tool to seat the new bearing on the lower boss against the bearing shield cup. This is not difficult.

    [​IMG]

    With the new, greased bearing in place, reinstall the stem assembly to the bike along with the upper greased bearing. You will have two protective shield cups piggybacked on top. Position the upper bracket on the stem and thread in the aluminum center stem bolt and snug it down enough to hold the bearings together for now.

    Install the fork legs and wheel assembly. Tighten the lower clamps on the fork legs but leave the upper bracket fork legs clamps loose for now in order to properly set the bearing pre-load.

    Setting the steering head pre-load:

    The factory manual procedure for setting steering bearing pre-load is to tighten the stem bolt to 20 NM, turn the forks lock to lock a time or two, loosen the stem bolt completely and then torque it back to 5 NM. Then tighten the center stem clamp and fork tube clamps and lastly torque the stem bolt down to 20 NM to secure the stem bolt.

    The time-honored traditional method of steering head bearing adjustment involves tightening the bearings down to put a slight drag on turning the front wheel while elevated and then slackening the stem bolt until the elevated front wheel will just fall from side to side under its own weight once bumped off centerline.

    I tried both methods with the X bike and ended up with a hybrid approach. I am skeptical of simply using a fixed torque number as suggested by the factory manual.

    First, I tightened the stem bolt down to 20 NM and turned the forks lock to lock two or three times to center and seat the bearings. I then loosened the stem bolt and then hand-tightened it with an Allen wrench until my elevated front wheel was hesitant to fall away on its own weight. I then backed the stem bolt out until the wheel would barely just fall away after a nudge from center.

    I then tightened the center stem clamp to 25 NM as well as the 4 upper fork clamp bolts to 25NM and finally went back and tightened the center stem bolt to 20 NM to secure it from backing out.

    After about 500 miles, I will re-set the bearing pre-load and then hopefully be set for many miles.



    ___________

    Steering head bearings are the same sets used on older BMW airheads and other models.

    SKF part number is SKF 320/28 (X or XQ etc) and includes the race, $30-40 each with race from suppliers.




    [​IMG]


    .
  2. rockydog

    rockydog just a guy

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    thanks for the posts, Leaf, good stuff
  3. keepshoveling

    keepshoveling DNF

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    Those are great leafman, thank you!
  4. jjmead1

    jjmead1 now THAT"S a bike!

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    don't boulder my Golden, CO
  5. XallengeXccepted

    XallengeXccepted Been here awhile

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    Thank you for the work you have done putting those together, leafman. It will really help a bunch of people out. On a side note, I wish we could get the front page to this thread updated a bit to include some of these helpful nuggets.
  6. eaglescan

    eaglescan Borrego rocks

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    Oddometer:
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    Langley,B C
    Another huge thanks to leafman for the time & effort for the info. I have a suggestion for all, start a book or doc. on you PC, and record the post # of all these useful reports. When we need to do some maint. ,it should be easier to find!. cheers, Steve
    P.S. , regarding the steering head bearings, I drilled into the headstock and put in a grease fitting. Pumped it full of grease and do it once a year. all good still, 69 000 km.
  7. gqelements

    gqelements Been here awhile

    Joined:
    Oct 26, 2012
    Oddometer:
    901
    Location:
    T-Dot, Canada
    after taking off the clutch cover I found the attached pictured 'bolt' underneath, covered in oil. The bottom of this 'bolt' is threaded and top is size 10 Torx. I think it may have fell out of the engine once I opened the cover.

    Any chance someone may know what this thing is? Not finding anything in the fiche.

    Really afraid to put this bike back together without knowing where this thing came from...


    [​IMG]
  8. keepshoveling

    keepshoveling DNF

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    Picture isn't showing up for me.
  9. BikerBobber

    BikerBobber Trying to get lost

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    Seeleys Bay, Ontario
    Don't see your picture.
    Go to Max BMW site https://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51546&rnd=07012015 and see if you can see something similar on the micro fiche.
  10. gqelements

    gqelements Been here awhile

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    901
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    Updated the image link, should show now. Unfortunately can't find anything on the fiche:
    [​IMG]
  11. Dutchgit

    Dutchgit Completely clogless

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    I wonder if it's anything from the engine. Never seen any countersunk head screw in there while I had it open.
    Closest thing is a screw from the generator but it couldn't have come out looking al unmolested.
  12. keepshoveling

    keepshoveling DNF

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  13. gwl

    gwl Been here awhile

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    TDC locking screw..... So I was doing a valve adjustment and I moved the bike while it was in gear. I did not use the TDC screw. So I think I have eveything lined up but not sure how to use the TDC lock screw thing. I took the screw out and put a screw driver in the hole and can feel a flat spot and then a hole as I move te bike while in gear. So do I line up the hole then screw the bolt in to hold the TDC in place? Or do I line up on the flat spot???????
  14. gwl

    gwl Been here awhile

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    I found what I was looking for on f650.com
  15. TobyG

    TobyG be happy :)

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    :ear
  16. gwl

    gwl Been here awhile

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    http://faq.f650.com/FAQs/TDCBoltFAQ.htm
    this link should work. But it says i can make a bolt that will lock the flynwheel in place. There for the fly wheel and cylinder will be in top dead center. if something happens to the cams you can line up marks
  17. TobyG

    TobyG be happy :)

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    That's what you meant...

    I thought you would've figured out where that weird screw came from :doh
  18. keepshoveling

    keepshoveling DNF

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    Different poster?
  19. TobyG

    TobyG be happy :)

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    Dammit, you're right...not my day :lol3
  20. Pejie

    Pejie old rider

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    May 4, 2007
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    842
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    Inman Valley South Australia
    let us know how you go even if the aprilia part is wrong at least it is another part number off the list. I'm after 2 sets & haven't been able to find an alternative. What wheels are on the XC? It is hard to believe they would be unique to the X.