Other 1990 XR250R Warm Engine Whining Noise – Cam Chain/Tensioner or Bearing Issue?

namilar

namilar

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:

  • 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 video where the noise can be heard
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.
 
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