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Is the chain supposed to do that?

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chain
4.3K views 15 replies 13 participants last post by  Fabspec  
#1 ·
Chain Jumping
I saw my chain was jumping whilst I added lube to it. I havent seen or felt anything off while riding, but I wanted to make sure that it wont become a problem down the line.
 
#3 ·
No, a chain is not supposed to do that. But not what you are thinking. Running the bike on the center stand with no load on the chain the chain will flop around like a fish. With that there is one section It looks like there are several links that are tight as seen when the chain really jumps right before it hit the 12 o-clock position on drive sprocket.
 
#5 ·
The jumping chain is caused when the inertia of the wheel pitches it faster than the sprocket is trying to rotate it. It can't, so the chain yanks the wheel again, inertia causing it to try to rotate faster again, etc. With the motor off, on the center stand in gear, try to rotate the rear wheel back and forth and watch the chain.

With the bike off & in neutral, try to pull a chain link off of the sprocket. Check a few random links. With a property adjusted chain you should not be able to pull a link completely off a tooth. if so, you may have either a stretched chain or worn sprockets or both.
 
#8 ·
With the bike on centre stand, the chain has a little more slack. The engine on idle is not like a four cylinder engine, they are a bit lumpy, ie, not smooth like a four cylinder bike. That engine the forerunner sport bike TL Suzuki was a trick to ride unless you were giving it to it, snatch and grab I call it. There is a trick that eliminates a lot of the snatchiness, all to do with cush drive on the rear hub.
 
#9 ·
(Very carefully) try to hold one of these against the rear wheel, to create some load for the rear wheel, and see if the chain will stop jumping. Of course be very careful and just bring the castor slowly against the spinning rear wheel.
Image
 
#12 ·
I suggest that if possible, make use of a swingarm stand rather than the center stand. The weight of the bike will bring the swingarm closer to lining up, thus reducing the excess chain slack vs the amount of chain slack while on the center stand. One may still need to drag the rear brake if required.
 
#14 ·
Just take your time and check the chain links with the motor off. You have a center stand, so just rotate the rear wheel enough to check a few links at a time. You should be able to tell if you have any kinks or sticking links. Check tension, etc.

Seeing the bike running on the stand seems to be an invitation for disaster.
JMTCW
 
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#16 ·
On the other hand.... I had the same problem with a DID X ring chain purchased new. As the chain aged (about 6K miles), the problem got more noticible. Removing the chain, I found a dozen links in the center of the chain (!) that were tight enough to not only "slap" the chain as was this case, but cause the bike to surge at low speed. I'm guessing a counterfeit chain... replaced and problem gone.