Chain slapping jumping under load.

Kivi · 04-06-2019, 07:50 PM

Hi,
I have unpleasant behaviour of chain jumping, slapping and making bad noise under load. This is evident on every faster takeoff (more throttle while releasing clutch) and the chain noise lasts only short time, usually while the clutch is in middle position. When I completely release clutch the noise stops. The noise comes from the area of front sprocket.
This behaviour is even more pronounced if I try to take off uphill on a harder terrain, where I need to keep the clutch in middle for a longer time while giving a little more throttle.
Changed front sprocket (JTF259-17), but that had not resolved the problem. Also, new chain fitted and the problem remains. Also, old chain lasted only 5000km! Rear sprocket is still ok condition (46t btw).
I have suspicion for sprockets misalignment. I have done rear sprocket fixture mod, in a similar way as Megadan did. Did not help this problem.

I made a video of the slapping noise! To make this video, and to make the problem audible on the video, I had to simulate harder takeoff: I lifted the bike rear, started the engine, put the bike in first gear, lightly pressed rear brake and started releasing clutch.

On the video is the old chain. New chain did not help.
One more vid, I hope you understand what noise in video I am reffering to.

Can someone help me with this?

04-06-2019, 07:50 PM	#1
Kivi Join Date: May 2017 Location: Serbia Posts: 217	Chain slapping jumping under load. Hi, I have unpleasant behaviour of chain jumping, slapping and making bad noise under load. This is evident on every faster takeoff (more throttle while releasing clutch) and the chain noise lasts only short time, usually while the clutch is in middle position. When I completely release clutch the noise stops. The noise comes from the area of front sprocket. This behaviour is even more pronounced if I try to take off uphill on a harder terrain, where I need to keep the clutch in middle for a longer time while giving a little more throttle. Changed front sprocket (JTF259-17), but that had not resolved the problem. Also, new chain fitted and the problem remains. Also, old chain lasted only 5000km! Rear sprocket is still ok condition (46t btw). I have suspicion for sprockets misalignment. I have done rear sprocket fixture mod, in a similar way as Megadan did. Did not help this problem. I made a video of the slapping noise! To make this video, and to make the problem audible on the video, I had to simulate harder takeoff: I lifted the bike rear, started the engine, put the bike in first gear, lightly pressed rear brake and started releasing clutch. On the video is the old chain. New chain did not help. One more vid, I hope you understand what noise in video I am reffering to. Can someone help me with this?
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