Another update here: Badddd news.
Went out the other night after having recently replacing the clutch pushrod and the seal. Seemed all fine, took it for a 20 minute easy ride and decided it was good to use the bike to actually commute somewhere. Well, I turned a corner onto a straight away and played with the throttle a bit and went through some rpms...
Then I look down and see the oil light glowing red. I immediately cut power and pulled over. HUGE trail of oil behind me and everything just dripping. Put the kickstand down and watched the engine bleed out. So after about 20 minutes, a guy drives by in a truck and has a ramp, gives me a lift a few miles down the road to my house.. Thank you Peter!
Today I decide to split the case, I uncover a mess. The needle bearing on the tranny shaft had exploded. This is the bearing behind the pushrod seal. The case has a some nice galling where the bearing was, and the tranny shaft is trashed. Surprisingly, the gears are all intact and everything else appears to be OK. I bought a complete tranny setup a while back but stupid me I didnt notice it was a 5 speed.
I may be very foolish to replace the tranny shaft and needle bearing and just put it back together... Im honestly considering it but I know its a bad idea. Im upset because my bike is #3xx off the line. I know there were only a few thousand 360s made, but it still seems like a very early production number.. If thats how Yamaha did things back then.
So now Im really not sure what to do. I did a compression test before I split the case and im getting 150lbs on both sides. The whole engine rebuild only had around 5500 miles on it. I have some options.... Find another 360 case and change it over. I can put the engine from my 400 in and maybe get that tuned well enough to get a couple rides in. I know nothing of the 400 engine other than its not seized and has around 16000 miles on it.
I will get some pics of the damage later.