I recently purchased a 76 yamaha DT250 that runs good. After riding around town a little I noticed a slight noise (best I can describe) like a bearing was going out. So I checked trans oil, it was full but smelled of gas so i changed it. rode it again same noise. Im' tearing down the motor to inspect for myself any specific help would be great. TIA!!

Nick, January 2005

IT WILL BE THE MAIN BEARINGS I EXPECT MATE YOU NEED TO SPLIT THE ENGINE CASES AND REPLACES THEM.TRY HOLDING THE GENERATOR IN YOUR HAND AND MOVING IT UP AND DOWN AND SEE IF IT HAS ANY PLAY IN IT ,IF IT MOVES THEN IT IS MOST CERTAINLY GOING TO BE THE MAINS OK

adam bike doctor, April 2006

Hi Nick. It sounds like your transfer oil seal has gone, they are easy to change though just be careful. Also if you are local to Hitchin in Hertfordshire I have a Yamaha 250 (type unknown) in my garage looking for a rebuilder (free to collector).

(Peter) mrfixitwilyeo@ntlworld.com, January 2005