03 CR 250 R, Engine noise, rattle

[mdcrazy]

2003 CR 250 R engine rattle. I have replaced the whole top-end(+/-10 hrs), bottom end crank bearings (5 hrs), rod and seals, new reeds (carbon fiber), cylinder replated and sized to wiseco std piston. Powervalves operate smoothly they are actually a little loose feeling in the cylinder, they have no resistance to operate when I disconnect the cables. I am about to replace the servo cables hoping maybe the powervalve has slack in it, I am getting poor lower end performance, bogging and not wanting to hold idle but performs perfect on the mid/high end. My bike sounds exactly like this one in link,

http://www.youtube.com/watch?v=bSxI-VQfTvI

[RedRider501]

My 03 cr250 makes the same noise at idle. Maybe not as loud though. Ive also had a 97 250 and 95 125 and they both made that noise too. I never had a problem out of any of the 3 bikes though.

[letitsnow]

My '03 sounds the same at idle.

I had a Husqvarna WR250 before the CR. The Husky was nice and quiet, but the motor weighed a lot more than the CR motor...

You might be too rich on the pilot/air screw, or have a fouling plug - causing the bottom end problem?

[mdcrazy]

okay so the noise is greatly reduced when I pull in the clutch. what is that exactly? does that mean the discs are getting loose?

[CrobarGreg]

I have a 1988 Honda CR250R with the same noise at idle.. everything is rebuilt.. Its driving me Crazy..  Did you ever find out what it was..   My research says its possibly the powervalve rattling.  or a rich condition at idle

[CrobarGreg]

2003 CR 250 R engine rattle. I have replaced the whole top-end(+/-10 hrs), bottom end crank bearings (5 hrs), rod and seals, new reeds (carbon fiber), cylinder replated and sized to wiseco std piston. Powervalves operate smoothly they are actually a little loose feeling in the cylinder, they have no resistance to operate when I disconnect the cables. I am about to replace the servo cables hoping maybe the powervalve has slack in it, I am getting poor lower end performance, bogging and not wanting to hold idle but performs perfect on the mid/high end. My bike sounds exactly like this one in link,

http://www.youtube.com/watch?v=bSxI-VQfTvI

I have a 1988 honda cr250r that makes the same noise and everything is rebuilt. It's the power valve rattling. It's common to cr's and its not a problem. A lot of guys rebuild the motor and the noise suddenly appears because the powervale is clean. The carbon on a well used motor can take up the play in the power valve making it less noisy. It's a cr thing .

[CrobarGreg]

okay so the noise is greatly reduced when I pull in the clutch. what is that exactly? does that mean the discs are getting loose?

if the noise. Goes away when u pull in the clutch pull your clutch cover check the condition of your clutch basket for deep chatter marks and check the clutch hub bearing while your in there. The wear on the basket can cause clutch noise. My clutch hub bearing was so bad the hub was scrapping the inside of the clutch cover. As for the hub it was worn and I filed the chatter marks down a little. Strange noises on cr's is a common thing. The best thing to do is inspect everything mechanically and leave it at that.