ok..on an intek ...the piston comes up on each cylinder 2 times... 1 time is the compression stroke....the next is the exhaust and intake stroke...right??..it looks to me that on exhaust / intake stroke......the piston pushes out the exhaust....and as the piston reaches the top of the cylinder the exhaust valve closes and the intake valve immediately opens to suck in the gas...(my valves are tighter on this stroke..no clearance at all.... is that normal?) ...the next stroke is the compression stroke...on this stroke the valves seem to be both closed for a long time..,so I put the piston at its highest point in the cylinder...and set the clearance to .005 on both intake and exhaust valves...did I use the proper procedure for setting the valves???..did I find TDC properly just by finding the highest point of the piston??...my problem is this...I Have a little backfiring at idle....very minor...and some smoke....at high throttle..can improperly adjusted valves cause smoke??