CMR250R
01-09-2007, 10:01 PM
I just rebuilt a 2004 yfz for a friend of mine, the crank seized, so I bought a crank, piston kit, brand new cylinder, main crank bearings, and a moose gasket kit. Everything was stock yamaha parts except the gaskets. The bike is also totally stock. The rebuild went well everything checked out, except when I went to check the oil in the reservoir tank the dipstick was dry. I put in 1.5 qts yamalube 10-30 in the reservoir and .5 qt in the motor like the manual says. Then I started the bike and let it run for like 5-10 min shut it down and I let it sit for like 30 seconds, I checked it and there was nothing on the dipstick... The motor sounds really great, no noise, no smoke, oil comes out the top banjo bolt in the cylinder if you loosen it -so it has oil getting to the top end. It just isn't going back into the reservoir. I took the top line off the res and I put my finger over the end to see if it was building pressure and it did but it kind of felt weak and a slow stream would flow back into the tank. During the rebuild I cleaned and blew out all the oil lines/pasageways. Now I'm totally stumped and really need help. Thanks in advance for any help you guys can give.