The important bit: SOLVED. Installed bolt into open threads in top right side of jug above power valve bearing.
I worked on this intermittently over the last couple months because I've been busy with many other projects. I got pretty well acquainted with the bike. The exhaust has been off and cleaned out. Its an aftermarket FMF full exhaust that could fit better. The power valve looks to be in good shape and moves properly. The area around the left side power valve bearing was full up to the bearing with oil/fuel--not sure if this is normal or if the bike was just loaded up from cold running. Second compression test came to 155psi--any data points for compression with a new top end? The right crankshaft seal did not work with a single lip seal--it was much worse. The seal that I removed from the bike was a generic SKF seal. I was able to track down and install a gasgas original seal and install it with the flat side to the trans oil. The SKF double lip seals I found on amazon.com would have probably done the trick. I could not find any indication that there is an o-ring around the crankshaft on this year. I've seen pictures of slightly newer bikes with that o-ring, but it looks different on this crank and I don't know if theres an o-ring hidden in there or not. If there is another collar that comes off the crank then the crank would need to come out of the bike and use a bearing separator to remove that collar.
The carbon fiber reed valves look nearly new like many things on this bike. I'm told that these came stock with carbon fiber reed valves but I don't have proof of that. I installed a new replacement carburetor (knock off from eBay $40 new) and used the jets/needle that came in the bike. I couldn't see any markings on the needle so I'm assuming it's stock. It hits pretty good, but I'll probably still look into that recommended replacement needle. New NGK spark plug went in just because. Checked and rechecked each part of the charging/ignition system and pinned out the wiring. Was getting ready to pull the top end and overhaul just to open her up and see the insides but knocked down a few last doors beforehand.
Removed the fuel tank and shook out all the old fuel mix and replaced with my trusted blend of 1:40 Lucas semi-syn and 93oct.
While I had the tank off I got a good look at the open threads just down to the right of the cylinder head. This is a threaded hole that goes to the area around the right-side power valve bearing. I don't see any logical reason for that to be plugged for the bike to run happy but I guess it needs to be. Any pictures/info I could find on the line shows just a little shiny nipple sticking out of those threads. Looks like an aluminum barb fitting from what I saw. Even read somewhere that it might be a crankcase vent? In any case, I installed a m6x1.0x10mm bolt in that hole and she lives! Whatever was in that hole before must have rattled out while riding and so the whole time I was just plain missing something. Have had three successful riding/tuning sessions with the bike thus far and it seems quite happy. Hopefully its all just routine maintenance and care from here on out
