Vespatude - A Vespa Blog: Open heart surgery

I didn't take the time to point out all the things that happened yesterday. I'll take a moment to bring it up now.

Mike told me to come on by his shop in the afternoon and he would help me set up the gear cables. I was a little hesitant because that would mean I would either have to take the scooter out on the main highway or cut through some very hilly neighborhoods. I chose the hilly neighborhoods.

Things started out pretty well, but at one point I was going up a pretty steep residential street and the Vespa began to backfire. It backfires because 1. the timing is off and 2. when the gears slip while the bike is under a load it causes the engine to over rev. Well, after a couple of backfires I heard a very loud POP! I thought, "Man, I've blown a gasket!" Thankfully, it turns out I had just blown the muffler off.

I alternated between pushing the scooter and riding it in the places where it was too hard to push. I didn't want to run it too much because it sounded like "Son of Harley." Heebie finally came to rest at the shop and the first thing we did was get the muffler back on.

It didn't take us very long to get the cables adjusted. Turns out I wasn't so far off with the work I had done. That made me glad. What made me sad was the fact that it didn't solve the problem. Turns out the gears would slip even with the cables correctly adjusted. So, we looked at other issues.

The throttle cable was not adjusted correctly. That is why the bike didn't want to idle.
Most of the grommets and rubber gaskets were missing from the bike. We replaced some of these and I went online to get the other ones we'll need. These are important because the scooter uses the frame and engine casing for air flow. If there are a bunch of holes in the frame you lose the flow of air.
We think the gear slipping is due to a worn cruciform. This is a little cross looking piece that engages and holds the selector to the right gear. Sometimes the square edges get rounded (or someone puts it in backward) and it causes the cruciform to "lose its grip" on the gear leading to... you guessed it... the transmission dropping out of gear.
When you push the throttle to get some high rpms, the engine bogs down. It is really like there is a rev limiter on the thing. I've noticed this when I have been riding the bike. When I have managed to get it in 4th, I can't get over 35 mph because the engine just says, "I'm not giving you anymore. I could... but I'm not."

All this (and a few more things - like the voltage regulator isn't working causing the bulbs to burn out when you reach high rpms) has gotten Mike and I to wonder what else it happening inside the heart of my little guy. So, we are planning on open heart surgery. I must admit this is kind of exciting because I would like to have the knowledge to be able to rebuild the engine.

So, that is where things stand. I will try to chronicle the surgery as I go along. Just don't get impatient... this could take a while.