Another day working on the ‘ped

Finally got the M02 running*!

video: click here

*After week of being solidly confused by the symptoms, and unable to get a clean plug chop (because it wouldn’t run for long enough), I found out why I had no power.  The symptoms were:

• no power
• no idle
• revs up to high rpms, occasionally dies
• after it ran, it would be hard to start

It looked like I was running rich when I checked my plugs, but it was hard to tell, since I have never seen a working moped plug, and its hard to tell from the pictures online what was is good and what was bad.  I thought that it might have been oil-fouled, and the waiting after the engine ran let the oil drip off the plug- it turns out, I was wrong.

Oil fouling?

The symptoms I described are actually being caused by a vacuum leak.  I think that the cool down was needed so that the metal would shrink and re-seal.  Based on a spraydown with carb cleaner, the leak is between the head and cylinder- so I need to either make or fab a new head gasket.  I have a new stock aluminum gasket on the way, as well as gasket paper…we will see which one gets here first.  When it eventually arrives, it will be time to take the head off the cylinder, maybe sand down the mating surfaces, and then put in the new gasket.

Ghetto Cruise Control (caps lock for my throttle)

The good news for this update is that I also went to harbor freight and picked up some swanky shop towels ($6 for 25!), and most importantly, a set of feeler gauges for setting the timing.  So far I have been using a piece of aluminum flashing that is about .03-.045 mm thick depending on the day, and after adjusting the points with the gauges, it started right up!  I can even start it with one hand, if i work the clutch with the other hand and tie the throttle up with one of those handy new towels.  Which I had to do to get it running for the vacuum test.