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

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.

Welcome, Sorry to hear of your troubles.
If you want to link the video, we will have a better idea of what kind of noise it is.
-BIG DAN

Also, just to clarify, when you say “lower left”, is that from the perspective of sitting on the bike or looking at the front end head on?

Hey, guys this is the noise
This noise is more towards leftside top