Hi guys, just found this forum and I think its great. I've owned a 1980 XT 250 for about 10 years, and for all of that time its had a frustrating, and so far unfixable problem. What happens is that the engine will run and pull fine, then suddenly the exhaust note changes, and the bike loses power, but keeps running. I also noticed when riding at night, that the exhaust header actually glows red when the problem is present. This had led me to believe that the engine is either firing after the exhaust valve opens or the valve is sticking. I replaced both valves and cleaned up the head, so I'm thinking ignition problem. The question is should I be looking at the CDI unit or the pickup coil or something else??