Another post on a long discussed topic, but here I go. '81 R65, ? miles but let's say 75K. In my possesion for about 3 months. When I bought it there was no service history so I started at square one. The valves, as recieved, were reasonably quiet but I wanted to retorque the heads and check everything. Followed the owners manual and turned crank to TDC, compression stroke, set to .004 & .008 -they tapped pretty loud. I'd adjusted the pillars in with large Channel-locks so they had near zero end play but still very loud. I adjusted five or six times using the factory method but the noise always remained -TACK, TACK, TACK. Two weeks into this I tried something different. I slowly rotated the crankshaft until the gaps were the largest and then set them to the .004 & .008 size. This occured on each side at the point where the other valve was at its maximum opening. Said another way, when the left exhaust valve was full open the left intake valve had its maximum gap. The reverse was true for the full open intake valve, the exhaust was max gap. Both sides were the same. It didn't make sense but after adjusting all four valves in this manner they went tick, tick, tick and the bike ran pretty well. I've been riding the bike for a month at least with lash set like this and I'm pretty happy with the noises but why was I not able to use TDC as the adjustment point?