This is the story of my '64 Vespa 150 - how it became mine and how it has given me a new vespatude.  I'll be recording the neat places I visit, the different things I do to make the Vespa my own, and - oh yeah - those reactions I get from both friends and strangers.

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Wednesday, September 20, 2006
Answering a couple of Vespa questions
There have been a couple of comments posted for which I haven't given a response. I'll take a minute here to answer them. Thanks for the comments, by the way, and I am always open to suggestions and scooter stories.

DigitalDion asked about the sidecar. Yes, you will notice in the pictures that I don't have the sidecar on right now. There are a couple of reasons for this. First, I am still making adjustments to the engine. When the sidecar is attached, it doesn't leave much room to get down and work on the engine. Until the adjustments are down to a minimum, I don't think I will be pulling the "pod" around.

That leads right to the second point about the sidecar which also leads to the second question I need to answer. Shok asks, "This is a new engine, are you watching the jetting and breaking it in properly? They may have ran it in some at Scomo but they are probably ata dif altitude." Yes, they did run it as SCOMO and I am trying to break it in -- that is the other reason why the sidecar isn't attached. I don't want to add that weight until I have run the engine in.

I have taken the bike and run it a low revs while it was parked and gradually increased the throttle to about 70%. I have also taken it on multiple short rides where I don't get out of third gear. HOWEVER, the statement about altitude and jetting is new to me. Can someone expound on that?

By the way, I think I have a theory about the reason that Heebie stalled while I was out driving to Sky Top but why he didn't give me any trouble coming back. When we started out on the trip, we went through a section of the city with lots of stop lights and hilly streets. I stalled the bike multiple times during this time. My guess is that I had way to much fuel build up in the bike and it just choked it and fouled the plug.

On the way back, the ride started without any stop and go. It was able to burn out all of the excess fuel and burn clean. I also took another route to my home that meant I didn't stop nearly as much. Not only did I make it home okay, but I haven't had any trouble since that time.

Thanks again for the comments, and again, I would appreciate some insight on the altitude/jetting issue. I'm not a professional Vespa mechanic and I have lots to learn!

It is great that your Vespa is running well!

I teach on three different campuses across the city, so I often have to scoot around in traffic. Today was one of those days. The sun was shining, it was nice and warm, so I hauled out my orange PX200 and did the trip between the University of South Africa and University of Pretoria without a hitch.

Have you checked to see that there is no dirt in the fuel line? On a previous vespa I owned it would also die at times. Then sometimes it would start, and other times it wouldn't (like you, I knew I was getting spark). I eventualy found that there was some dirt in the fuel line (rust actually) that was getting into the carb and clogin the fuel jet.

Once cleaned and flushed she ran like a dream!

Basically the higher the altidude the thinner the air (I think atmospheric pressure is less), so if I'm correct, but double check, higher altitude needs a smaller jet, less air so you should have less fuel, low altitude means more air so you need more fuel. Again double check, and I also have no idea how your altitude compares to Scomos, I just brought the whole thing up so you consider everything and don't go too lean. I hope this is helpful.


Listen to Shok, he speaks wisdom.
Scomo or Scooterworks should have instructions on jetting on their website, you maybe able to find the sweet spot with carb adjustments, or you may have to get a new size of jet.

Good luck

Oh BTW the jetting could totally be causing your stalling.

I hadn't checked your blog in awhile, glad you've got the new engine, and the scoot is running.
She's a Beaut!

if you could tell me the sizes of the jets that are installed in your carb I could compare them with other setups for 177 ccm zylinders. What brand is it?
You have to watch the ignition timing as well. It could be that you changed it while changing the ignition plate.
Here is a list of ignition timing degrees for various zylinders (watch out for "Z├╝ndzeitpunkt"):
What carb do you have? An SI 20 or 24? If you own a 24 then you should have a 118 to 120 main jet installed.
You also have to select the right spark plug. If you take a "hot" one, it'll work fine on short routes but will burn a hole into the top of your piston on long routes.
If you take a "cold" one, then it'll burn not perfect and you'll have to clean it from time to time but you'll be safe from overheating.
If you use a Bosch spark plug you should use W3AC/W4AC or W3CC/W4CC (the difference between A and C is long or short thread of the spark plug).

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