Driveline Backlash 2010 GSA

Discussion in 'GS Boxers' started by viz, Jan 1, 2013.

  1. viz

    viz I Ride Ms Piggy

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    I have noticed recently that the driveline backlash on my 2010 GSA seems to be increasing - stick it in 1st gear on the main stand and rocking the rear wheel back and forth produces about 2"+ of movement with quite a hefty clunking noise which seems to be coming from within the gearbox rather than the actual driveshaft or surrounds. This clunking noise is also heard throttling back and forth, especially in the low gears. Bike has just turned over 45,000 km (27,000 miles). Everything else is normal, gearbox smooth as silk; bike is meticulously serviced.

    When manoeuvring slowly it is a pain - much like a slack chain. Normal? Within tolerance?

    viz
    #1
  2. Multiplicity

    Multiplicity Been here awhile

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    I get the same free movement on my 2013 GSA. If you're hearing a clunk, check those U-Joints.
    #2
  3. DSTEVENS

    DSTEVENS Been here awhile

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    My 13 GSA has a lot of driveline "slop" if you will, something I am not used to. Most noticed in first gear. First BMW so what do I know except I dont like the sloppy feel in on and off throttle in first gear. Only 743 miles on it and sloppy from first ride. D.
    #3
  4. def

    def Ginger th wonder dog

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    Drive line lash is the sum of the clearances of several mechanical parts:

    1- Clutch/input shaft spline.
    2- Gearbox
    3- Transmission output shaft/front u-joint.
    4- Rear u-joint/final drive input shaft spline.
    5- Final drive.

    When these clearances are converted to rotational lash, it adds up to several rotational inches of what many call slop.

    Next time you have the rear wheels of your rear wheel drive car off the ground, check the "slop" in the drive line with the car in gear.

    As for low speeds, that's what the dry clutch is for...slip it when you're at low speeds in lower gears.

    If you try to modulate the throttle of a large twin-cylinder powered motorcycle at low speeds without feathering the clutch, you'll experience plenty of drive line snatch regardless of chain or shaft drive.

    That's why the Shriners rode Cushmans in parades.
    #4
  5. Multiplicity

    Multiplicity Been here awhile

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    I marked my tire and it's about two inches of movement at the rim :rofl
    #5
  6. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    My 2010 is the same. Relax, as Def sez, it`s normal.
    #6
  7. kk3an

    kk3an Adventurer

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    My 2013 GSA is also the same. Had a Super Tenere also with significantly more lash still, so I'm not concerned about the GSA.

    Dan
    #7
  8. def

    def Ginger th wonder dog

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    See? Dan knows lash.
    #8
  9. def

    def Ginger th wonder dog

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    I thought you were gonna say, "Trade it in on a Cushman". :eek1

    Happy New Year. :wave
    #9
  10. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Back at ya!!
    #10
  11. bailer

    bailer Adventurer

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    My 2013 GSA is exactly like this also. I noticed it after my 1000k service and was a bit paranoid I guess. Perhaps it was more evident just because i was manoevering out of the crowded dealer lot?!?

    I know the final drive oil was done correctly because I did it myself, and so it is nice to see this amount of lash is normal, (2"at rear tread).
    #11
  12. DSTEVENS

    DSTEVENS Been here awhile

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    2013 GSA and it has SLOP SLOP SLOP, and I don't like it but THEY ALL DO THAT. So I here. Its 2013 and it makes clangs and bangs and rattles and squeaks.:rofl D.
    #12
  13. def

    def Ginger th wonder dog

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    The boxer engine and driveline layout does not react well to unloading and loading the throttle, especially at low speeds and in low gears. Since the boxers are no longer race bikes, using engine braking by shifting to a lower gear produces driveline snatch and discomfort along with strange noises.

    Learn to keep the driveline loaded (under load) until you must slow then, merely let off the throttle and shift down into lower gears as the speed of the bike demands lower ratios to eliminate engine lugging. For example, as I approach a stop, I pull in the clutch and downshift in conjunction with the reduced bike speed until I reach neutral or first…left foot down and rear brake clamped at stop.

    My gearbox never clunks or clanks with noise due to engine RPM and wheel speed differences. You’ll have to practice a bit but throttle blipping with downshifting or down shifting and releasing the clutch to use engine braking is just plain unnecessary in my estimation and places undue strain on the driveline.

    Remember, you have a rubber driveshaft damper that help reduce driveline clatter but it can do only so much. Smooth application of throttle and managing engine back lash with the clutch will produce very smooth shifting and driveline operation.
    #13
  14. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    #14
  15. Schlug

    Schlug JockeyfullofBourbon

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    put something on and stay in that position.
    [​IMG]

    Here's a 'new' attempt at an Airhead driveshaft
    [​IMG]


    See right there where the large OD part of the shaft mates with the small OD part of the shaft? There's rubber in there. It's the black ring you can see there. It can go bad, and in this very forum we've had people whose bikes have slipped under load and at speed when the rubber is hot and given up, and then when the thing cools down it runs fine. It's caused quite a bit of confusion.
    #15
  16. Britome

    Britome Get Free

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    Mine does the same and scared the crap out of me. Then I did the same teat on three other GSAs and found this to be normal.
    #16
  17. Backlash

    Backlash Adventurer

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    Gees--I got it all over. The BMW, Jeep, Silverado, John Deere, and you should see what happens when I cast my light lure with my baitcaster into the wind.
    #17
  18. Chat Lunatique

    Chat Lunatique aka El Gato Loco

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    Thanks Bobby. Damn....I just replaced one on an 1100 and never even realised it was full of rubber.
    #18
  19. Schlug

    Schlug JockeyfullofBourbon

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    put something on and stay in that position.
    No problem. I am sending mine out to Bruno as a matter of fact. It has notched in one direction, not horribly, but enough that it needs addressed.

    I found another used one on the flea market. But its condition is not much better. Still functional while I send the original out.

    68,000 miles on the piece. Bruno will charge 380 USD to rebuild it with u-joints with grease fittings that can be serviced. That is about half what a new OEM shaft is. I'll keep the other one as a spare in case a fellow GSpotter has an emergency.
    #19
  20. def

    def Ginger th wonder dog

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    Has anyone found a service that will change the rubber damper in the DS?
    #20