you still have this bike? would love to see an update video. careful with the oil, had a mate think his 'frame oil' was for the suspension. he checked the dip stick and it showed up dry as usual (bike was cold). he then proceeded to fill the frame with hydraulic oil and hydro locked the motor. i would recommend checking oil level as you warm up the bike. keep checking until oil level stops rising and bike is pretty much hot. ProbstMotosports, turtlemartin4558 and rwcasto in the comments also have very good advice.
Pretty common for the YZ to get red hot at idle… mid body gaskets can allow air into carb and lean it out too- you can by them now on Rocky Mtn ATV. The mid body gasket does not come in a rebuild and they have those funky screws too.
Just watched your other video stating you were at 3 turns out on the mixture screw and I wanted to mention you need to start at 2 turns out and turn out until you hit your highest point in rpms before it starts to stumble back down then adjust your idle screw down until you're happy with it. Somewhere between 2 and 2.75 turns out should be your sweet spot
Leaking valves, to lean, to rich, air leak, exhaust leak and idling too long are some of the possible reasons the header is glowing red I was having the same issue on my 04 YZ 450fs!
you still have this bike? would love to see an update video. careful with the oil, had a mate think his 'frame oil' was for the suspension. he checked the dip stick and it showed up dry as usual (bike was cold). he then proceeded to fill the frame with hydraulic oil and hydro locked the motor. i would recommend checking oil level as you warm up the bike. keep checking until oil level stops rising and bike is pretty much hot. ProbstMotosports, turtlemartin4558 and rwcasto in the comments also have very good advice.
Pretty common for the YZ to get red hot at idle… mid body gaskets can allow air into carb and lean it out too- you can by them now on Rocky Mtn ATV. The mid body gasket does not come in a rebuild and they have those funky screws too.
Just watched your other video stating you were at 3 turns out on the mixture screw and I wanted to mention you need to start at 2 turns out and turn out until you hit your highest point in rpms before it starts to stumble back down then adjust your idle screw down until you're happy with it. Somewhere between 2 and 2.75 turns out should be your sweet spot
Leaking valves, to lean, to rich, air leak, exhaust leak and idling too long are some of the possible reasons the header is glowing red I was having the same issue on my 04 YZ 450fs!
FYI you have to check your oil after you have it warmed up a bit 😂 I did the same thing on my wr450
You definitely should wash it at some point.
Check the timing. Sounds/seems like it’s too far advanced. That was the problem with my 05 wr250f.
He has redone the timing 11months ago so it should be good