The exhaust pipe after painting during the rebuild last year.

This morning I figured I’d take a slightly different route on my ’85 Vespa PX from the East Village to work in Midtown in an effort to keep things interesting.

Turns out I needed to do nothing of the sort to keep things interesting. Turning from E.14th St. on to 3rd Avenue, my exhaust decided to work it’s way loose, leading to an almighty racket that scared the crap out of pedestrians gathered on the busy corner waiting to cross the street.

Fortunately for me:

• This has happened to me before when I was testing the bike after the rebuild, so the familiar lack of compression and almighty racket telegraphed the problem immediately.
• I was in second gear traveling less than 5 miles an hour.

30 seconds later and I am parked at the side of the road and under the bike with a wrench. The retaining bolt had worked it’s way completely loose and was getting dangerously close to working it’s way backwards into the back tire. I was lucky. If it had jammed against the moving wheel at best I would have tore the tire, at worst, the entire exhaust assembly would have sheared off the bike. And that’s not even considering what could have happened to me the rider with this happening at speed, in traffic. The source of the noise came from the fact that on the other side of the exhaust the output from the engine casing had also come loose, no doubt vibrated loose because of the retaining bolt. In all, the entire exhaust (stock PX) was literally hanging on by a thread.

Using my torque wrench I tightened up the retaining bolt as tight as I could get it and then reinserted the exhaust on the engine side into the engine casing and tightened that up. The job took less than twenty minutes but required removing the spare wheel to get enough leverage to tighten the retaining bolt.

Lessons learned?

1. Always keep a set of tools on your bike if you own a two-stroke scoot. Two strokes rattle significantly more than modern autos and stuff works its way loose. It’s a simple fact which leads me to:
2. Preventative maintenance. My biggest mistake was not taking the time at the weekend to spend 15 minutes looking over the usual nuts and bolts offenders (hub nuts, wheel nuts, wing mirrors, and clearly exhaust) and making sure they’re tight. The amount that the retaining bolt had come loose would suggest it had been working it’s way loose for the best part of a week.
3. I’m going to look into finding some grip washers for the exhaust. The previous owner had at one point removed the exhaust and temporarily fitted a Sito Plus. I suspect that when the stock exhaust was reinstalled he lost a grip washer or two in the move.
4. There’s a short length of the rubber sheath that protects the gear cables near the exhaust that is damaged and exposes the cables. It’s been this way since I bought the bike and I didn’t know why. Clearly now I can see that this happened in a previous exhaust incident with the pipe coming loose and burning through the rubber. I greased it up last Fall as a preventative measure but some point down the road I need to replace this rubber. At least now I’ve realized how this damaged occurred in the first place.

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