Posts
10
Joined
4/16/2020
Location
Douglasville, PA, USA
Edited Date/Time
4/22/2020 10:46am
Hi all,
So I’m having an engine noise issue with my 2001 RM125 and hopefully you guys can provide some guidance. In the video, you’ll hear an underlying clanking that is consistent with the RPM’s and a strange noise as the bike winds down from being revved up. The video does not do the underlying noise appropriate justice, it is louder in person and definitely not typical for a 2 stroke. This noise started suddenly last summer at a local mx track and since then I haven’t ridden it much out of fear something will be damaged even further. There doesn’t seem to be any power lost in the bike either. The piston was Wiseco and compression on the bike was decent but less than ideal so I recently rebuilt the top end myself with a type B Vertex piston/rings and had the cylinder professionally replated and the noise was unchanged by the rebuild. I don’t think the noise is coming from the power valves. Also, the crank had zero up/down play at rebuild and there is no play in the flywheel. The noise is unchanged if I pull the clutch in.
I’m fairly certain it’s a bearing issue in the bottom end but before I tear apart the engine, I wanted to see if anyone had any experience with a similar noise and what your issue was.
I appreciate any advice in advance!
Also, sorry for the odd camera angles. I was trying to get my phone's mic to pick up the noise as best as possible so I was trying different mic locations to do this.
So I’m having an engine noise issue with my 2001 RM125 and hopefully you guys can provide some guidance. In the video, you’ll hear an underlying clanking that is consistent with the RPM’s and a strange noise as the bike winds down from being revved up. The video does not do the underlying noise appropriate justice, it is louder in person and definitely not typical for a 2 stroke. This noise started suddenly last summer at a local mx track and since then I haven’t ridden it much out of fear something will be damaged even further. There doesn’t seem to be any power lost in the bike either. The piston was Wiseco and compression on the bike was decent but less than ideal so I recently rebuilt the top end myself with a type B Vertex piston/rings and had the cylinder professionally replated and the noise was unchanged by the rebuild. I don’t think the noise is coming from the power valves. Also, the crank had zero up/down play at rebuild and there is no play in the flywheel. The noise is unchanged if I pull the clutch in.
I’m fairly certain it’s a bearing issue in the bottom end but before I tear apart the engine, I wanted to see if anyone had any experience with a similar noise and what your issue was.
I appreciate any advice in advance!
Also, sorry for the odd camera angles. I was trying to get my phone's mic to pick up the noise as best as possible so I was trying different mic locations to do this.
Cheaper to rebuild than replace cylinders and cases.
Take off the cylinder side cover and check it out. You can replace it with the 2002 part number
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Also, it’s important to note that the crank bearings had zero play in them. The races looked fine and the ball seemed to look fine as well with the exception of the metal flakes stuck in the bearings. I will be taking a very close look at the bearing fatigue when I pull them to see what the ultimate mode of failure is. I want to find the source of this metal. Any suggestions on where to look would be appreciated otherwise, I’ll be sure to post what I find when I get a chance to dig deeper in a few days.
Thanks for the feedback so far!!
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