I bought this '12 GS-150 two years back. I regularly change oil myself at 800-1000km and had its clutch plate changed and tuning don't a month after buying it. The mechanic adjusted the valves without feeler gauge at that time, and since then another mechanic might have adjusted them again while I wasn't in front of the bike. Recently I have started doing its maintenance by the book, and today opened it up for valve clearance check for the first time. The screws were tightened so much that I couldn't insert the 0.05mm gauge in either valves. I checked and rechecked that I was at TDC of compression stroke, and then adjusted the intake to 0.05. The issue arose when I couldn't insert any thickness gauge in the exhaust side even after taking the adjuster screw out completely. The rocker arm seems to be pushing down on the valve, and if I try hard enough to move it up a bit, it feels like a spring is resisting this movement because it forces down on valve when I let it go. I checked intake side's arm by taking its adjustment screw out, and while it didn't push on the valve like exhaust, it isn't moving freely either.The image of rocker arms isn't clear in the repair manual (uploaded PDF on the forum) there probably is a spring shown on one rocker arm attached to its shaft. But if it already pushes the rocker arm forcefully on the valve even at tdc and the gap exists between its cam side, doesn't it negate the purpose of any clearance set on the valve side? Even if I force a 0.13mm gauge between the arm and valve somehow, the sprung will close that gap when I'll remove the gauage. Or is something messed up in the head cover? I haven't closed up the bike or started it because I would rather fix this problem first, even if it means replacing some out-of-spec component.Excuse any mistakes. My internet isn't working so I had to write from mobile.
Edit: On a second thought, assuming there is a spring designed to keep the rocker arm pushing on valve all the time, then the clearance can be adjusted IF the arms other side is kept in contact with cam by pulling it up, inserting the the gauge and tightening the adjustment screw.