A little embarrassing, but I am willing to share so others may learn from my experience yesterday. Exciting day, first fire-up of the engine that has been disassembled on my workbench for ten years. When I started the project I was going to build a dragbike, so I had a 74 crank indexed/welded, bought some high compression Henry Abe two ring slipper pistons, APE cylinder studs/nuts, a set of APE cams which required modifying the head for lobe clearance, high performance springs and shim under bucket followers. My priorities changed, but I wanted the bike back together so I sold the big cams and installed a set of Webcams with .395 lift. I touched up the valve seats with a Neway cutter, lapped the valves in and did my initial valve clearance adjustment on the bench one cam at a time. I installed the head on the motor to check for piston/valve clearance and did the final valve clearance measurement. When I did the final assembly and checked valve clearance again, I had 0 clearance on the #3 intake, WHAT? Cams back out, shim SOMEHOW had popped out of the recess in the retainer! Cams back in final measurement, everything cool except #3 intake is .18mm which in retrospect probably would have been fine! The next morning I decide to just pop out the intake and reshim #3 to get it in the .10 ti .15 range. I loosened the front cam removed the intake, reshimmed and back together. Yesterday, initial start-up, fires right up on 3 cylinders! #1 exhaust cold, spark, check, fuel, check, compression 0!!!! Remove exhaust, set #1 cylinder at TDC on compression stroke, peek into the exhaust port, and the valve is open. DAMMIT! Remove camshafts, AGAIN! and discover that the shim was popped out of the retainer! Back together, check clearance on ALL cylinders and everything is cool, motor sounds great! I think I was pretty lucky to have a mild cam profile and plenty of piston/valve clearance or it probably would have been a sad day! I can't explain how the hell the shims "popped out" TWICE, but it did happen. I didn't even need to use the shim under bucket with these cams but I had the parts and decided to use them. I should have had all this documented on video like Swest, but the audio would have been X-rated!
Happy now! Mike