This bike was my father's and is quite sentimental to me and when I received it it hadn't been started for a decade.  It seemed as the engine was permanently seased but after opening it up it was super clean.  It the piston with a wood block a couple time and turned the bike upsidedown as we figure it was hydrolocked.  Well I think that had to be the case because this is leaking very heavily beneath the engine and I'm sure it's the yamalube based on the color.  Took a photo of where it was leaking after having driven it a ways.  Doesn't seem to leak much after it's settled and cooled down.  I know it runs super rich due to Colorado's altitude.  Any suggestions would be greatly appreciated.

 

You did check the clutch/tranny oil? Perhaps the main output/drive sprocket seal is leaking? you'll have to pull the cover to see.
Sneezles61

I would agree with Sneezles, but sat here in Blackpool looking at your pictures it's hard to tell.
If you had 2 stroke oil, or as you've termed it Yamalube, leaking, it would be from the bottom of the small cover 
that's positioned on the front right hand side of the motor as you're sat on the bike.
Simply remove that cover to see if you have oil in there . Currently , from here, it looks like gearbox oil that's leaking from either the selector shaft or gearbox output shaft seal as Sneezles says.

Just give it a de-grease & wash off, change the transmission oil. Check there's still twostroke oil in the lube tank. Bleed the pump till constant flow--'only take a minute'-- out the small screw with fiber washer. Make sore cable is operating, then "go ride it". Good model 'that'. Doubt it was hydraulocked as that would turn over with the plug out, but if you needed to hit the piston with a wood block it's more likely just piston grown into the cylinder. If 'that' freed it up & she runs then keep on truckin considering it now runs if i'm reading it right. Rich running could be a number of things like exhaust tail muffler or airfilter choked etc, or just need a good ride & rev out.

Could not find an accurate diagram of a '72 DT250 (without downloading one from Tech here).but had a similar leak problem on my '74 360. Turned out to be the seal on the clutch actuator there on the bottom of the crankcase. Dirt and debris gets on the shaft and "props" the lip of the  oil seal open. There are methods to clean without removing the oil seal (external operation) similar to cleaning fork seals. Thin, semi rigid plastic trimmed to look like a lowercase "q" (without the center cut out). It is then curled to the shaft size and eased between the seal lip and the shaft. Pull debris out around the circumference of the shaft.