OK I can hold it in any more, I had a 370 main jet in for the toomey, and then found out that the missing chunk the carb cap lined up with the cutout on top of the carb and was not sealing at all, so I stuffed it with high temp gasket maker and let it sit, took it for a lap around the yard and it was running really rich. In the meantime I had also pulled the flywheel and stator plate and checked the main seal, as well as moved the timing back a bit closer to stock (1 1/2 to 2° advance over stock).
So even though, it may not have been completely leak free it was now running quite rich, and not longer had the major leak.
I had my little girl on the tank "she demanded I take her for a ride" and it was loading up bad, so I nailed it in first, eased off to shift, realized that I had alot more rpm and power to go (because of the new pipe, rimming,etc), so I slapped the throttle back open, and when I actually tached out first, I slapped second (real dry loose dirt and gravel on top of really hard clay).
A second and a half later it lost spark, and rolled another 10 feet up the hill tile it quit with a clank, clank. When I let off the brakes and it didn't roll backward down the hill I knew I was in trouble.
Found this (first pic below) in between the threads and insulator of my sparkplug. Thankfully when the piston dropped the exhaust side skirt, a piece almost immediately fouled the plug. I would hate to think what would have happened if it would have been wide open pulling 8k or so when the pieces starter getting between the crank/rod and the case and binding the motor up.
The piece by itself sacrificed it's life as a piston skirt to snear up and shut the motor down, before there was any sign of what was going on. I would like to thank this little piece of cast, and celebrate its efforts as heroic.
Here is the poor used and abused piston, it was wet and oily when I pulled it, the scoring was caused by a defective exhaust flange.
There are some well washed out signs of the dome being hot in the past, probably from when it was running a 230 main jet without and airbox lid and with a DG pipe as this is how the previous owner had it jetted
When I pulled the flange to fix the leak, I found that the little pipe had been welded into the flange crooked causing the pipe to stick out just under 1mm and hold the bottom of the flange out away from the jug. Funny thing is it didn't have aNY kind of a seat that fits the inside of the exhaust gasket like the Toomey does.
The first time I had it out for a long trail ride, and put it through a puddle a little over the foot pegs deep on the way back to camp, it got tight on me and was hard to kick after sitting for a couple minutes. I let it sit another 20 minutes and then rode it easy for a little bit before loading it on the trailer. I fixed the leak and put another 10 or 20 hours on it since. (It's hard to keep up with the half hour or so rides around little valley in my back yard)
I am really beginning to wonder how this motor ended up with a new wiseco bottom end, a Pro-X piston (ART S1), and a cylinder wall that fit's it soo loosely, the piston w/o rings drops straight thru without any resistance, and rattles around like its got an Extra .010" clearance.
It's like it blew, someone honed it out and dropped in a piston, something else went wrong (cracked skirt) and took out the bottom with it. So they got a Wiseco ready to install crank, standard sized cast piston, honed it out again and threw it together.
Anyhow the cylinder wall looks good. I gotta split the cases and get the rest of the piston out of my motor (new main bearings and seals while I am at it). Sent the top off to KOR for head rechamber / cylinder bore, hone, chamfer, and a forged wiseco. Before it goes out its getting the KOR home port treatment.
This will go along, with the 28mm miKuni VM, boyesen power dual stage (?) reeds, Toomey B1, high power coil.
Before I tore it down I did leak test, the case was now leaking through split between the case halfs at the bottom front come to find out this is also where the chunks of cast were wedged in between the rod/crank and the case. I don't think it was leaking from here initially ,because other than a little grime from the header leaking splooge, it was pretty clean.
3 or 4 hours after the incident, when I sit it up on the rack to plug the exhaust port. I noticed a good bit of thick kinda bronze brown stuff had actually seeped from the case. Sure enough when I pushed the foot pump, air and more of the bronze brown lube from the bottom end came running out as fast as I put it in.
So I guess it's Dropped skirt due to excessive cylinder wall clearance and scoring due to the exhaust header not sealing to the exhaust port.
I also found the clutch plates to be around 70% worn with the exception of a friction or two just below the middle was worn nearly smooth I did notice the steel plaTE tabs were nearly aligned in this area?
(huge main jet, and i always ride WOT) 
