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<blockquote data-quote="namilar" data-source="post: 233525" data-attributes="member: 7194">Hi guys,I have a 1990 Honda XR250R with an intermittent whining/whirring noise that only seems to happen once the engine is warmed up.The strange part is that the noise comes on randomly while the engine is running, but if I shut the engine off and restart it, the noise usually disappears immediately. It may then come back again later once the bike has been running for a while.The noise seems to be loudest around the left side top of the engine. Pulling the clutch in makes absolutely no difference to the sound.Things already noted:<ul>
<li data-xf-list-type="ul">Noise mainly happens when the engine is warm</li>
<li data-xf-list-type="ul">Comes and goes randomly</li>
<li data-xf-list-type="ul">Restarting the engine makes it disappear</li>
<li data-xf-list-type="ul">Pulling the clutch does not affect it</li>
<li data-xf-list-type="ul">Seems loudest from the lower-left side of the engine</li>
<li data-xf-list-type="ul">It is more of a smooth/high-pitched whine or whirring sound rather than a knock</li>
<li data-xf-list-type="ul">Cam bearings have already been replaced to address this noise</li>
<li data-xf-list-type="ul">Oil is reaching the top end</li>
<li data-xf-list-type="ul">I have attached a <a href="https://youtube.com/shorts/TmFDcsJApiU?feature=share" target="_blank">video</a> where the noise can be heard</li>
</ul>I’m currently wondering about the flywheel/stator area, balancer shaft/balancer bearings, crank main bearing, or possibly something in the cam-chain drive transmitting the noise through the cases.Has anyone experienced a similar intermittent whining noise on an XR250R/XR250?Any ideas on what I should check first would be appreciated.</blockquote>

[QUOTE="namilar, post: 233525, member: 7194"] Hi guys, I have a 1990 Honda XR250R with an intermittent whining/whirring noise that only seems to happen once the engine is warmed up. The strange part is that the noise comes on randomly while the engine is running, but if I shut the engine off and restart it, the noise usually disappears immediately. It may then come back again later once the bike has been running for a while. The noise seems to be loudest around the left side top of the engine. Pulling the clutch in makes absolutely no difference to the sound. Things already noted: [LIST] [*]Noise mainly happens when the engine is warm [*]Comes and goes randomly [*]Restarting the engine makes it disappear [*]Pulling the clutch does not affect it [*]Seems loudest from the lower-left side of the engine [*]It is more of a smooth/high-pitched whine or whirring sound rather than a knock [*]Cam bearings have already been replaced to address this noise [*]Oil is reaching the top end [*]I have attached a [URL='https://youtube.com/shorts/TmFDcsJApiU?feature=share']video[/URL] where the noise can be heard [/LIST] I’m currently wondering about the flywheel/stator area, balancer shaft/balancer bearings, crank main bearing, or possibly something in the cam-chain drive transmitting the noise through the cases. Has anyone experienced a similar intermittent whining noise on an XR250R/XR250? Any ideas on what I should check first would be appreciated. [/QUOTE]

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