I believe you are correct Carter. I FINALLY got some time today to dig into her and here is what i found. I see a ton of oil build up just everywhere, crank, piston and the gasket that goes between the head and jug. When i pulled the 4 bolts that hold the jug down they all had oil on them especially the front 2. I show a comparison in the pics. Hopefully tomorrow ill have some time to take the piston off the rod real quick to check it over but for now i thought id give an update and get your guys expert opinions.


  

Yeah the studs shouldn't come out of the block like that either. Get um cleaned up and dry and use some Loctite on them to re-set them. I torque studs that come out a little more than what the nuts are supposed to be. Hasn't failed me yet.

Thats some good advice, it was only 1 that came out. If im not mistake i think i can replace those crank seals without having to split the case? Just need to drill a hole in the seal, find me a screw to go in the hole and my trusty vice grips for yanking.... there somewhere on the bench lol

My studs just didn't want to come out but needed them for another set of cases. Did get 3 out but number 4 broke off flush. wasn't a happy day. Not sure i used the others after that as were all feeling like suffering before turning. Used an old style remover that got hold of it at the base so the best place. Think were loctite'd in but don't need to be.

Enduro Nut you are correct about the procedure for replacing crank seals. 

So i been shopping around for some crank seals and from what i can tell both sides are different. At least according to the part #. Im curious what you guys would recommend buying? i see i can buy sets on ebay for just under $10 but those are made in china and we all know how great their stuff is. Im not so sure about NOS for fear of dry rot after sitting on the shelf for so long.

I live in the UK so your access to parts is better than here. You might get seals from Rocky mountain and they might be used on a current model of some description . Put the numbers in their search and see what comes up. Bearing suppliers can supply seals and it's possible you might find something there that's not Chinese. In the end ,as i'm finding here, you might have no other option .Double lip seals are what you need . If you end up using anything that looks round from China, check it out as it's not always the case. You can find stuff in the Japanese market ,i have but you need a go between sometimes to buy and need to spend ex amount.
With regards to the compression readings. When you put oil down the bore, the oil acts as a seal on the rings.
That's why your readings changed after a while. A mate races Karts and only uses a twenty to one ratio with racing oil. Why ? Because he gets higher combustion chamber pressure at high temp.
I would say, new rings going in at least and clean the living daylights out the ring grooves . If the pistons goosed ,it would do no harm to measure the piston to bore clearance (0.045 -0.050 mm ) and if that's okay , de glaze the bore and new piston and rings. When you start the bike use mineral 2 stroke oil. It has a higher zinc content and prevents glazing. Don't leave it idling . at least give it the odd rev . Once it's had a couple of tanks of fuel through then you'll be okay to use any 2 stroke oil.
Then you'll find some thing else to occupy the Yamaha bit of your mind .
Dave

So this 360 is STILL fighting me to the death, this is where im at. NOS piston, NOS rings, cylinder professionally honed, the stator has been rebuilt by DEET, new crank seals and top end gaskets, compression reads 110 PSI before break in which i thought it would have more but feels fine. I stuck a new plug in her NGK B9ES, fired her up and she sounded pretty good but i was unable to dial the carb in as good as id like simply because i was trying to adjust the clutch but she seemed close to where i want it.
The issue that i continue to have is it shuts off. I cant tell if its ignition or carb giving me fits.  After a short ride time today it shut off as if someone hit the kill switch. I pulled the plug and checked the spark and it was weaker then before. I then checked the points which i had set at a snug 14 thousands which they were still at that position. I opened them up to 15 and sure enough i had what looked like decent spark, so i fired it up again and it ran for about 3 seconds after 5 kicks then died. I pulled the plug and had no spark, i tossed in another used plug  just to check spark and it was very weak, checked points again and they were still at 15.
I have cleaned the carb probably a good 30 times, replaced that one O ring in there and have the needle height set at the 3rd position. I should note that the plug didnt really looked fouled, a little wet but not like black but keep in mind that the plug only has like 10 mins of run time on it. My next step is to pull the carb again and check to see if it has stock jets. I know when i bought it the guy said he used to ice race with it. Im pretty sure i have already looked into this 2 years ago but im really stumped here.
Ive read tons of posts on here but nothing seems to work with this girl. I know these are supposed to be timed 2.9mm BTDC but i dont see why i cant just set the points at TDC? ive done this on tons of chainsaws and my DT250 and LT2100 and they run great. I should also note im using a 75DT250 coil as well. Any ideas here?



 

Condenser?

Fuel tank cap not venting properly?

New condenser when DEET rebuilt the entire stator. im 100% certain the stator is fine with the exception of the point gap which from what ive seen should be somewhere between 12 and 16 thousands but then again these are supposed to be timed 2.9mm BTDC.
I doubt its the fuel cap since spark went away but i can try that tomorrow if i can manage to find some plugs.