ok I have a whining noise coming somewhere from the front of the fourwheeler on my Yamaha warrior. it was rebuilt a couple weeks ago and rode fine then the exhaust studs backed out and I had to ride it about a mile back to my house without the header on. I replaced the studs and now it makes a whining noise. its not jetted properly and runs lean and hot but it has since its been rebuilt and the whining just occurred after the exhaust stud replacement. I checked valves changed oil and looked around at it but it still does it. at first start it doesn't do anything only afer it gets hotter and the hotter it gets the louder it gets. even hot it isn't noticeable at idle but as you rev it up its gets really loud and it quits back down as it revs down. cant figure out what it is. also the power is the same no noticeable difference from before its only the noise I just don't want to mess it up and have to fix more than neccesary

 

Wow, driving it without the header is not good on the motor. That could burn the valves, but a burnt valve wouldn't make a sound. I'm not sure why that would make a whining sound and not lose power. The sound may not be related to the exhaust studs. The whining could be coming from the timing chain. Or, worst case scenario, you messed up the piston rings by riding it without the header, but if that was the case, it should be using oil/smoking/low on power.

 

ya I know its not good, I was cringing the whole way home. I melted my boot trying to hold it on the head. also it doesn't smoke or do anything all power is still there im starting to think its not anything to do with the engine but have no idea what it is. I don't thik its the timing chain because it never did the sound before.unless riding whithout the header could do something?