I've just reassembled my Cams after reshimming and during the process of aligning the flywheel up to TDC by turning with a socket on the nut, i noticed that on the compression stroke it was very easy to turn, although there was a bit of compression it was still easy enough to rotate the crank with one hand while with the other holding a torch on the alignment marks to check for TDC. I could also hear a slight hissing sound which sounded like it was coming from the exhaust side of the head, indicating a stuck valve that wasn't seated correctly. it was possible to go through the complete cycle, compression/release/exhaust etc by hand, never once having to relieve any pressure via the de-comp lever? Now i know this shouldn't be, as it would be nigh on impossible to do this by hand if the combustion chamber was sealed properly? so, have i a sticking exhaust valve or is it more likely to be that the compression gases are escaping down past the piston rings? How costly is this to fix, i know it's a "head-off" job to check the valves but what about repair costs, is it going to be expensive do you think or is it a matter of re-lapping the offending valve? the cams are aligned correctly, facing away from each other and the marks are at 9.12.3 and all valves are closed and clear of the buckets, also the de-comp lever is seated correctly and not contacting the far exhaust bucket with a little play in the lever. Could this be a burnt valve from having too tight a clearance between the cams and buckets, prior to my re-shimming them? I thought in my last few rides that it felt like it had lost power but then i'd presumed it was my "being used to it"...... Also, another thing i noticed while feeling the pistons movement up/down the bore while turning the crank was that it felt very easy to turn (as mentioned ealier) and would tend to "jump" past TDC, just a fraction and would always be out of alignment which would require going round again to try to line up the marks? is this an indication that i have a lot of play in the needle roller bearing or is it much worse than that, big end bearings or worn crank? It doesn't show signs of burning oil so i'm presuming the big-ends ok, but without wanting to completely strip the engine down i'm not 100% sure i am correct that it is? How hard is a sticking valve to fix? before i decided to re-shim, the bike ran good and started pretty easy and the jetting seemed ok if not a little rich? if the black sooty deposits on the rear fender are anything to go by. The plug also seems to be good too, not oily or black? It's just this ease of pushing it through the compression cycle that is worrying me, it shouldn't be THAT easy should it? thanks for any help guys.