I have a Foxi Moped, Sachs engine, 1977. It was bought in good condition and ridden quite a lot. Lately I have had to do some adjustments here and there. I recently cleaned the points, because it was running kinda like the timing was not quite there. I ran sandpaper through it, both sides. I also cleaned out the exhaust, though there was not much carbon. I also adjusted the spark plug. The manual says the gap is .20, but after all this, it would not start!!!! Before all this, it would start immediately. I reset the plug to .30, and after some furious pedalling, it started but was very rough and sometimes popped. some how the timing got way off?? Without a timing light, how can I check the point gap? What else can I check to figure out why its off time?