DR650 Cush Drive Bearings

Discussion in 'Thumpers' started by BergDonk, Apr 7, 2011.

?

How's your > 96 DR650 Cush Drive?

  1. Lateral movement of sprocket 0-1 mm

  2. Lateral movement of sprocket 1-3 mm

  3. Lateral movement of sprocket 3-6 mm

  4. Lateral movement of sprocket > 6 mm

  5. Bearings changed @ < 5,000 kms

  6. Bearings changed @ < 10,000 kms

  7. Bearings changed @ < 15,000 kms

  8. Bearings changed @ < 20,000 kms

  9. Bearings changed @ > 20,000 kms

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  1. Dirty Harry

    Dirty Harry Coffee Addict

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    How many miles are on it?

    When you say fell out, you mean they just fell out whole and you put them back in, or they crumbled out in pieces? Play usually means its time for a new (quality SKF) bearing and cush rubbers.

    I believe the north America torque rating is 72.5 ft-lb with cotter pin. Thats a nut buster with a small wrench, so maybe you didn't torque enough?
    #41
  2. mouthfulloflake

    mouthfulloflake Not afraid

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    20K, I orderded a bearing kit, Pit posse or something like that, probably NOT as good of quality as the SKF.
    I used the little cheater bar in the tool kit on the wrench, but probably still not 72ft lbs.

    I will retorque and re-check, thanks
    #42
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  3. Dirty Harry

    Dirty Harry Coffee Addict

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    That seems to be a long life compared to other hub bearings/rubber.

    I guess that brings me back to the root of the issue and the point of this thread:

    Is everyone just sticking with the stock parts or has a better multi-bearing solution, or modification to the hub been found that better supports the hub so it lasts much longer?????
    #43
  4. LexLeroy

    LexLeroy Nerds Rule

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    Fellow inmate dr_steve pioneered a fix that uses an NA 4904.2RS bearing where the middle spacer normally goes. I changed his design somewhat when I bodged up a DR650SE hub with an 18 x 2.5 rim for my XR650L (17mm axle), but here's a picture again. Notice the inboard needle bearing.

    [​IMG]

    I favor this approach because it doesn't molest the hub and it also retains the outboard seal in the sprocket carrier. I don't have many miles on this but I believe that Steve is pretty happy with the modification. It's not hard to do but it takes someone with both a vertical mill and a lathe to do the work. I'm happy to describe the process in more detail if anyone is interested.

    Good on ya' Steve.
    #44
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  5. sandwash

    sandwash Long timer

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    This one at 30K was pretty sloppy.
    [​IMG]
    #45
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  6. Dirty Harry

    Dirty Harry Coffee Addict

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    That is unfortunate that there isn't a plug and play solution yet. Do you think using two stock cush bearings has a posibility of working? The second bearing would stick out past the hub obviously, and you would still be stuck making a custom spacer.
    #46
  7. LexLeroy

    LexLeroy Nerds Rule

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    4 1/2 years ago I implemented a 2 bearing solution for my DL1000. The big DL had lots of room available between the sprocket carrier and the swing arm so I had much more latitude in my approach, but there was still some machining on the sprocket carrier and left hand spacer that needed to be done. Here are the parts ready to be put into place,

    [​IMG]

    and then on the bike. Notice how much room there is between the sprocket carrier and the swing arm, unlike the DR650 and my own XR650L.

    [​IMG]

    Take the time to review all of the effort and expense that BergDonk has put into finding a solution. There's not much that he hasn't already tried, but there's always value in another set of eyes looking at the problem.
    #47
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  8. Dirty Harry

    Dirty Harry Coffee Addict

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    I will do that, thank you for the reply!! :)
    #48
  9. BergDonk

    BergDonk Old Enough to Know Better

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    I'm now using a 4205 2RS in place of the stock bearing. This is a double row bearing that lasts a lot longer than the stocker and doesn't fail as catastrophically. All it needs is a machined down spacer. Its not so wide than the seal won't stay put like the earlier 3205 I used as per my post above.

    I'm also using a 3804 2RS inner. I did have an issue with this, but it proved to be the result of a worn axle, so new bearing and axle and good so far. I'm also considering 1 or 2 6904 2RS on the inner. I haven't been able to source the needle rollers that DR Steve used in sealed configuration, but the above ball bearings seem fine.

    If an inner bearing is used, the stock outer bearing should be OK too, but the 4205 makes it much better all the same, BergDonk proof so far in fact :photog

    [​IMG]

    Fitting the inner bearing is a very straightforward job with just a lathe and 100 mm or so chuck with sufficient bed clearance.


    [​IMG]






    [​IMG]

    Centre hub on chuck with inside out grip on stock bearing bore and make the inner bit round.





    [​IMG]

    Then make a bush to fit.




    [​IMG]

    Press it in.



    [​IMG]

    Shorten the stock spacer by the width of the new inner bearing of your choice.

    Then I machined out the bush for a press fit for the bearing, fitting it after the spacer.
    #49
  10. Zapp22

    Zapp22 ZAPP - Tejas

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    i have read countless posts on this topic over 10 years, and still don't see a good answer.

    in part, I know from large mftg Quality Control measures that all the care and/or optional 'fixes' is only good if the statistics PROVE the goodness. there is a dearth of stats for the aftermarket bearings.... we read happy posts where original oem bearings fail, the pilot replaces with some other than OEM part, carefully planned and executed, and then we hear no more. what is the failure rate on "other-than-OEM" bearings??? answer is, we have no good data. Anyone who knows the metallurgical & mechanical issues that get involved [and the immense variables such as the driver, engine braking, braking, terrain, water, salt, ice, CHAIN TENSION, etc etc] - just because something appears to fit well and has "good" internals does not portend a longer life or happier ending.

    anyone know of any real data that would demonstrate "other-than-OEM" success better than original?

    also; anyone know of any data that would indicate that there were "bad runs" of bearings in some years or serials?

    also, it seems consensus among knowledgeables that while good cush lugs are nice to have, they add nothing to the longevity of the bearings. Is that true or guesswork??
    #50
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  11. sonic reducer

    sonic reducer Been here awhile

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    bump, these are great questions. especially the bit about cush rubber newness vs. bearing life. it seems questionable that short bearing life on the cush drive could be attributed to the rubbers.
    #51
  12. thump!

    thump! Adventurer

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    Zapp22 asks very relevant questions. No responses though.

    LOGICALLY more bearing surface and additional bearings to resisting twisting and the subsequent lateral forces on the 6205 bearing make sense but still no actual long term data. I agree with sonic reducer in doubting the cush rubbers have a significant effect on bearing life. They are SUPPOSED to allow some movement and even the small amount new ones allow is more than enough to side load the 6205 - we're talking thousands of an mm here folks - those cush rubbers compress much more than that under load. I'm wondering if maybe the best path forward is to simply replace the sprocket carrier bearing every time I replace the chain (which turns out to be more or less 10K miles depending on how much water and grit the chain sees). The 6205 2RS bearing is not expensive and it's really quite easy to replace even without a press (and will almost drop in if the hub is heated and is the bearing cooled).

    So, for now that's my plan. Maybe I'll add a 6205 2RS to my "always carry" spares just in case.
    #52
  13. kezzajohnson

    kezzajohnson kezza

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    Yep. That's what I do, in fact I carry an entire set of bearings Front, rear and Cush. They just stay in my spares tube all of the time, don't really take up much space and are not very heavy.
    #53
  14. Mugwest

    Mugwest .

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    Timely bump for a great thread. Good knowledge and thoughtful experimentation, gents :D
    #54
  15. motolab

    motolab Long timer

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    Here's what I came up with for phreakingeek:

    [​IMG]

    [​IMG]

    Regards,

    Derek
    #55
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  16. motolab

    motolab Long timer

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    Agreed. I'd be much more concerned about chain tension.

    Regards,

    Derek
    #56
  17. BergDonk

    BergDonk Old Enough to Know Better

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    Looks good. What bearing did you use for the spigot if you don't mind sharing?
    #57
  18. motolab

    motolab Long timer

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    Thanks!
    6004.

    Regards,

    Derek
    #58
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  19. thump!

    thump! Adventurer

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    Is there lathe work involved? Would you sell this as a kit? Or maybe as a conversion starting with the customer's stock hub?
    #59
  20. LexLeroy

    LexLeroy Nerds Rule

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    I used a vertical mill to get the bore for the inner bearing concentric to the outer bearing's bore. My lathe doesn't have adequate swing to hold the hub itself, plus my imported 3-jaw chuck holds work about .003" off of center. I did use the lathe to make the spacer for the inner bearing however.
    #60