An Atlanta friend, Joan, rides a 1997 Honda Helix scooter. When the Helix first came to the U.S. in 1986, my dad traded in his Honda Elite for a Helix. The thing was huge, especially by scooter standards. Powered by a 250cc engine, it was, as far as I know, the largest scooter in history at that time. I always thought it was pretty cool, so when Joan said her Helix needed work, I was very interested.

At around 35,000 miles, her engine seized up on the interstate, a result of the engine running without enough oil. It had probably been burning oil for a while, but below a certain level, it seems to have gotten ugly pretty quickly. (Please note: this mechanic is uninterested in who’s to blame for an engine running without oil. In Joan’s defense, the dipstick was broken, and the owner’s manual doesn’t explain how to check the oil without the dipstick.)

She took it to an Atlanta scooter/motorcycle shop and they reported, after installing a new muffler and rear brake shoes, that the engine was “pouring out oil” when it ran, and that maybe it needed a cylinder base gasket. That’s not a cheap repair, so Joan decided to get the scooter back from them and ask me if I’d like to try my hand at it.

I decided it was time to learn how to remove the engine from a scooter. It’s a dirty job on a bike that’s been leaking oil, but it’s not terribly complicated. With the engine sitting on a table, I finally saw that the oil leak was from the airbox, which had a crack in it. No problem, that’s easy to replace. (It would have been easier still had I seen the problem before removing the engine.)

The new airbox went in. I test rode the bike to school, three miles away. I stopped for a newspaper and some watery coffee. I returned to the bike to see that it had vomited what must have been a quart of fresh oil into the parking lot’s gutter. (Sorry about that, QuickTrip station!) I rode it very gently the last quarter mile to school.

It turned out the leak was a result of combustion pressure pushing past the cylinder and into the crankcase. Since the crankcase breather system runs into the air intake system, this means the oil from the crankcase is pushed up and ingested by the carburetor — at least it was above 45mph, which is when the bike ran out of power and let out a smoke cloud so thick I couldn’t see through it in the mirrors. (I knew the Helix should be good for 65mph, so I realized something was wrong before noticing the cloud behind me.)

With my instructor/friend Mike’s help, I made the decision: I’d have my first engine rebuild project on a real engine on a real bike that someone was going to ride for at least another 35,000 miles.

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