I had that same bike back in high school…got it off a buddy who had just rebuilt the motor…$20.00 the rear mono shock was shot but that bike ripped! I miss the sound and the smell of these older two strokes.
Sorry sold it about a year ago, had quite a bit done to it, ported cylinder, vforce reeds, modified head, ufo throttle kit and torque wing, sucker would go.
I sold it last spring, one thing that helped it out quite a bit was a thunder products ultimate flow ultimizer 'UFO' you have to modify the carb slide a little but the benefits were well worth it, sharp and quick throttle response for under $50 shipped it is a bargain, highly recommended.
What were you doing before you took off, warming up the water? lol That was the nice thing about the air coolers. You could start them and pretty much take off because the cylinder expanded about the same rate as the piston as they would heat up together a lot more closely.
I can see just by you sitting on the bike, how much easier it is to keep your elbows up and corner with out the modern high rise ape hanger bar set up.
Man you had rhis thing modified a bit, I seen them power wheelies and that undeniable strength in acceleration- kids think these old bikes weren't worth beans....but lol....yea...you know.....yz250 n yz490s are capable of just about ANYTHING even till this day.
Yeah it had quite a bit of mods done to it, unfortunately I sold it awhile back. That's ok as I have a 83 Suzuki RM500 now and of course it's modified also it turns and handles just as well as the YZ not bad for an open class bike.
Sold mine for $2000 had a lot into it, one thing about these you wii be lucky to break even, mine was heavily modified, just depends on what the buyer thinks it's worth to them.
There was never a need to lean the bike over to aid starting. The float bowl fills up when the bike is upright just fine. But I guess it may help to see if your overflow lines are plugged with dirt. Not a big deal. It is pretty easy to be victims of false tribal knowledge. :)