This will be a typical, really long, Chris Robertson post... You've been warned.
My 1978 Peugeot has begun acting up again. There was a discussion about it in <a href=" https://www.mopedarmy.com/forums/discuss/1/38632/38632/">this thread</a> about a month ago.
The problem at the time was that after running it for fifteen minutes or so and getting the engine very hot, it would be impossible to start for fifteen minutes or so until (I presume) it had cooled off.
Since then the problem seemed to go away on its own.
Two weeks ago, this moped got stolen (and then found), but I don't think it was abused. When I got it back the thief had carefully cleaned and detailed the ped, and carefully taped the wiring so that it didn't look as messy --so I don't think any damage was incurred while the moped was in the thief's care (for about 48 hours). I mention this just for completeness' sake.
Yesterday I went on a trip to a hardware store on this moped. This trip is almost completely wide open throttle travelling. It was running perfectly (except for a little bit of sputtering towards the end) all the way there (about 5km / ~3 miles). When we got to the hardware store it was closed, so we turned around and started to head back. The moped was never shut off. About 1km later I lost all power. As I slowed from 50km/h (35mph) I tried everything I could think of to get the engine to sputter. I choked it, I toggled the ignition kill switch, I fiddled with the wiring. Nothing.
Assuming that this is a similar problem to the one I had before, I sat down at the edge of the road and waited fifteen minutes for the moped to cool off. The engine had cooled off quite a bit (I could put my hand on the exhaust), but wouldn't start. I took the magneto cover off and touched the flywheel. It was <i>extremely</i> hot. Hot enough that I could have burned my fingers if I hadn't touched it gingerly.
I began the walk of shame home. After about twenty minutes of walking (and at the top of a hill) I jumped on and managed to eventually get the thing to fire up. By this point the magneto had cooled off quite a bit. The moped ran perfectly well the rest of the way home.
Obviously I have a heat-related problem.
<li>Is it normal for a magneto to get that hot? Could that be the problem?</li>
<li>Any ideas what else it could be? Any measurements I should take to help diagnose?</li>