Long time lurker, first time poster. 1978 Puch Maxi that I have restored to basically stock condition. Only change was going from a 12 mm bing to a 15 mm bing. Starts very easily. However, you can clearly see exhaust leaking between the head and the cylinder. And when you spray carb cleaner around the gasket the engine slows down. I have read everything there is to find in the wiki and done a thorough search on this forum. I have followed the instructions for sanding down the head and the cylinder using plate glass to make sure it is flat. Problem persists. I’ve tried using a gasket, no gasket, gasket with the sealer. When I use a gasket with sealer, my cold compression goes from 120 PSI to 150 psi. However, once the engine starts running the leak returns. If I takeoff from a stop with the choke completely on it runs fine and hits about 26 mph. However, once you stop, you have to put the choke on again to get running. It’s obvious that it’s getting way too much air. I can hold my finger half over the air intake and it will run just fine. A bit hard to ride with my finger down there. I’ve also tried changing out jets, From everything down to 60 all the way up to 82. Nothing makes any difference. I’m turning to the gurus on here for help! My plan was to eventually go with a new top end set up. Should I just go ahead and do that and quit messing with the stock head and cylinder?