A whole lot'o slapping going on....

Discussion in 'Parallel Universe' started by ebrabaek, Dec 7, 2012.

  1. ebrabaek

    ebrabaek Long timer

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    After I got the 18 inch tubeless build with the stock gearing supersprox, I have had my share of chain slap. I have adjusted the chain loos ( about 5cm as per manual), and tight at 3cm....... 2mm camber left...... 2mm camber right.... And nothing seems to help. Have had non of this before the new wheel. Excel 18 inch tubeless....supersprox. A fantastic combo..... Chain is the stock installed after the recall. Had 1500 miles from new when I changed the wheel. I know about needing to change it all, when installing a new sprocket, but through out my life on bikes.... I never had this. It happens at neutral torque, on the bottom 1/3 of the chain. Drives me nuts. Next is a new DID chain with a master link. I was just curious, if any have had this happen after the taller 18 inch rear....???
    #1
  2. Motorfiets

    Motorfiets Long timer

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    does it have a tight spot possibly?
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  3. ebrabaek

    ebrabaek Long timer

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    Could be... I will check this tomorrow. This is the second build rear wheel, and they both started this, so perhaps, unless by chance they both have a tight spot, I'd like to blame the chain. It gets worse with 2 up..... That's why I tried to go over/under with tension, as it changes a little with second up. It only happens at neutral torque. pull a little power, it goes away... or let go of the throttle a little....It goes away. I have checked with the builder, and they have been awesome, and are stumped as well. It is time for a DID with a master link anyway. :D:D
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  4. mapuda

    mapuda Crash Tested

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  5. ebrabaek

    ebrabaek Long timer

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    I actually have. I am in the planning stage of a Carbon Fiber/K-39 chain guide. It most likely would solve this. Only thing is ....This issue has me stumped, and I know there are a few fellow inmates that runs the same conversion as I. I was just curious if they had experienced anything similar. Mine will be savoring the same function as the BRP in the linky above, but situated further forward, and with a few more tricks. Cup holder.... toolbox....Etc......Uhhh.....and...ehhh... extra zip ties..... :D:rofl:clap
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  6. ebrabaek

    ebrabaek Long timer

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    Just checked for rear sprocket roundness. It is 100% true, and round. I would expect nothing else from this great wheel builder. Before switching I did not measure the with of the stock sprocket, and compare with the supersprox. Perhaps some one would be so great as to measure their stocker.....:freaky:freaky
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  7. Mike.C

    Mike.C Stelvio Dreamer!

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    Maybe not, I have installed the BRP guide and still have to listen to Sir Slap a Lot making his presence known. FWIW with standard sprockets and chain it never happened, installed Supersprox and he reared his ugly head. installed a DID chain and he calmed down a bit, but is still a distraction.

    After talking to a mate with a KTM 990 I now just ignore it, or try not to have the engine revs/ground speed in the slap spot.
    #7
  8. Snowy

    Snowy Long timer

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    Too tall a gear for the road speed.
    Mine has a couple of tight spots, a slightly out of round rear sprocket, and a chain guide.
    It slaps. You get used to it.

    But my chain and rear sprocket have 50000km on them, so new ones will be on there soon. I think the tight spots have worn the sprocket weird.
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  9. ebrabaek

    ebrabaek Long timer

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    I see... Did 525 it is then..... I was thinking that with a chain guide between 1/3 -1/2 forward from the rear sprocket would minimize it, but yet as you mentioned might it help, as my dry has one, and is stil slapping. What gets me here is that it does it at all speeds....all gears... Neutral torque.
    #9
  10. runnin4melife

    runnin4melife Been here awhile

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    Would be interesting to try the stock sprocket and see if it disappears (I know you don't have one now). The only thing I can think of since you have a relatively new chain is that perhaps the cush drive in the new hub is culprit. If it is exceptionally rigid or has too much play it could lead to a slack issue that can compound with a tight spot and creat a rather annoying slap. The only real way to determine this is to change one component at a time.

    This could explain the "at all speeds" issue because even at a steady speed the cush drive is bouncing back and forth just do to rotational inertia and friction differences etc... I am not an engineer but have had enough physics (for the inevitable science driven drivel that will undoubtedly appear on this post).
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  11. ebrabaek

    ebrabaek Long timer

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    I don't think it's too tall geared... at least in my case, because when I first got this fantastic combo, I started with a 45 tooth rear supersprox, but as it was great for the trail, it was too low on the streetside, So I went to a 41. I guess I will just ignore it.
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  12. ebrabaek

    ebrabaek Long timer

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    Could be.... The cush drive for the 950 ( Excel billet hub) is tight. I would say a bit tighter than stock. The rubber pieces are a bit smaller, but harder to press in. I will start with the Chain. What is your with of your stock sprox..... ??? I think the Supersprox is a few mm's thinner....
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  13. runnin4melife

    runnin4melife Been here awhile

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    Will measure when I get home (2-3 hrs) do you want width and then the radius and circumference?
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  14. ebrabaek

    ebrabaek Long timer

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    Just the with Adam, as I just looked, and the Supersprox has about 1.5mm space to "wobble" the chain....
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  15. mapuda

    mapuda Crash Tested

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    Does the chain slap at speed but with the clutch in? You mentioned it slaps at zero torque which I take to mean not under a load. Maybe it is the pulse of engine firing that causes the chain to slap?

    Just trying to wrap my head around it.
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  16. ebrabaek

    ebrabaek Long timer

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    Perhaps I did not explain that correct....:D. I guess there are always torque as long as you are either holding a steady speed, or accelerating. Mine is only at steady speed. The moment I am accelerating... it disappears instantly....or if I let go just a little bit. So in short.... At steady speeds only. All gears.
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  17. runnin4melife

    runnin4melife Been here awhile

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    6.9 mm for the rear. This was eye balling it though as I couldn't find my calipers. Which must be with my lost right handed snips. It is probably 7mm though.
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  18. ebrabaek

    ebrabaek Long timer

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    Well... That shoots that one. Supersprox is 7.28mm wide..... Ohhhh well.
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  19. runnin4melife

    runnin4melife Been here awhile

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    Just found the beast, I have 7.23mm - 7.25 mm depending on where. :norton
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  20. JRWooden

    JRWooden Long timer

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    I can't find the thread now ....

    But one inmate here or on F800Riders was installing a tensioner that pushed the chain AWAY from the bottom of the swing arm - this would provide some extra insurance against slapping compared to tensioners that push up ... it does slightly reduce the "wrap angle" of the chain on the sprockets, but it can't be by much.....
    #20