I'm doing some basic maintenance on my 82' GS850G (Maybelline). She ran really well up until the end of last season but developed a bit of a lean stumble this year that has gotten progressively worse. So far, I have:
1) Checked the valves and changed out two shims (2.55).
2) Gone through the entire airbox to reseal as necessary (air boots were nice and soft but there was a serious lack of rubber on the outsides and middle joint of the box itself).
3) Checked petcock fuel line and vacuum line, neither leaks. Petcock delivers nice consistent fuel in the prime position.
4) New plugs gapped to spec + checked wires for cracks (they are good as is spark).
Anything I'm missing? Yes, the four elephants in the room are the carbs which I need to pull and clean properly. I am leaving for a 2 month fieldwork trip next week so will wait to do this when I'm back (graduate student by profession). I plan on documenting this procedure when I get round to it - figure it'll help other newbies out there! (I've done carbs before on my 72' CB350. They're much easier to sync and tune, so the four together will be interesting)
Sorry for the long winded story, I thought it important to give an accurate background. The question I have has to do with the fuel cap. I have noticed a hiss of air escaping regularly as I move the tank on and off the bike. The hiss occurs with the fuel tank entirely disconnected to the bike (vacuum and fuel hoses are not connected) leading me to believe the gas cap could vent better. Is there a specific way to ensure the cap is venting appropriately? I unscrewed the two screws on the back of the cap and saw four holes; two with threads where the two screws go and two which are clear. Are there any specific passages I should look in for obstruction? Places I need to blow compressed air through?
Maybelline has been sitting for a while, I don't mind though. I'm happy to make sure everything is done well before I start her up and take her out!
Thanks for any help! Also, any members in and around Western Massachusetts? Would be happy to make your acquaintance!
Cheers!