Hi all, my engine developed a knock and I couldn't find the problem. I tried syncing the carbs but it still knocked. So I went to adjust the valves and when I went to take off the adjustment cap from the back of the stator housing it was gone, so was the 12x40 bolt. So I went to order a new bolt and cap from partzilla and sure enough the bolt is obsolete. They had the cap though. So I searched eBay and there were only three available. So I purchased one from someone in California, it got to MD. In 4 days. The cap came from GA. That took 6 days go figure. Anyway I put in the bolt and cap and started the engine and the knock was gone. I ran it 1-200 Miles and it started knocking again. I opened it up to find the bolt was loose again. I tried tightening it with the plugs in and while it was in gear, I got it as tight as I can and started it, now it sounds like a sewing machine. I'm afraid that it will come loose again so the only other thing I can think of is to hold the crank bolt while trying to tighten it. Maybe evan use some thread locker on it. I'll try what ever it takes to not have to take the engine out. Just thought I'd share my adventures. Thanks