KAWASAKI ninja250SL drive-sprocket and noise

[Japanese(日本語)]

Annoying noise

I bouht a second hand KAWASAKI ninja 250 SL  in December 2023. But I was annoyed by the strange noises which become bigger when I run 5th or 6th geer. I heard the sound of iron or something scraping.I bring my motorcycle to the shop but they said that it was no problem. I was not convinced, so I researched it on the internet and I got an information.  The drive sprocket which is not a genuine parts sometimes makes a wired noise, because of lacking a rubber which makes noise easy.

I opened the sprocket cover and noticed that the previous owner changed the drive sprocket to SUNSTAR 378. And the chain guide plate was scratched abnormally. The chain guide plate was set upside down. I guess the previous owner might made a mistake.

I thought the strange noise was come from this upside down chain guide plate. I tried to run without the chain guide plate, But it still made the strange noise. I guess the chain guide plate was already fully scratched not to make the noise.

SUNSTAR 378
scratched chain guide plate. In this picture, the chain guide plate was set upside down.
You can see the chain guide plate over the cover, If you set the guide correctly.

 

Changing the drive sprocket

I went to a motorcycle supplies store and ordered the genuine part(KAWASAKI 13144-0577) and have it changed.
that made the strange noise gone. ( additionally, the shop clerk scrape the chain guide plate to set normally)

Before the change: You can hear the strange noise. especially around 10th seconds.

After the change:  You can’t hear the strange noise.