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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Tuesday, March 07, 2006
What is going on with my wiring?
Yesterday I went home after lunch to grab the Vespa. Once again the weather was just to nice to have it sitting at home. Nothing really to relate. Riding is starting to just seem normal.

There is something I am hoping scooterists out there might be able to help me with. It is the last part of the scooter that I just can't get a handle on. It is the electrical issues that are bugging me.

The bike came with a 12 volt upgrade. I have not done anything except replace the wiring harness. I speced it to be exactly like the old one. I still have the same problems as the old one!

I will put in all new light bulbs. Things start off just fine and if the lights are off or only the pilot light and tail light are running, the scooter runs great. When I turn on the headlight, things start getting funky. The bike will run fine as long as I keep the throttle about one-third open. As soon as I rev past that the bike bogs or stutters. If I flip off the headlight, the bike picks up just great. If I leave the headlight on, it will ultimately blow along with other bulbs in the system.

Any ideas? This is driving me nuts. The headlight bulbs are not always easy to come by. I would appreciate any help someone might give.

Here is one thing that is somewhat different - thought I can't see how this would be an issue (I don't think). I took the sidecar off and have plans of making a "quick attach" connection for the pod. That meant I had to cut the wire going to the sidecar lamp. I closed off the connection with a regular female electrical plug. The idea being that I would put the male end on the pod side and when I attach the sidecar, I will simply plug it in. However, that means that the circuit is not connected. Would that make any difference? I wouldn't think so, but I'm learning that Vespa electrical systems don't always follow convention!

The first thing I would suggest is check the voltage at all the bulb locations and increase the RPMs. If you don't have one, you can get an inexpensive one at radio shack. Use the AC setting on the meter unless you're running a battery. The 12V upgrade should be putting out 13 volts or so but not much more than that. The voltage should not go significantly higher as RPMS increase. The job of the voltage regulator is to keep the voltage from going much beyond that, despite increasing RPMs. If it does, you may have a bad regulator. If it's not putting out 12V, that's another problem. If your total light wattage consuption is exceeding the capacity of the elctrical system, the voltage will drop and you will lose spark. Check voltage and see where you are there first.

Another thing to consider is the bulbs you've ordered. If you tell the shop you have a VBB they will automatically send you 6V bulbs. Make sure you tell them that it has the 12V upgrade. 6 volt bulbs will almost certainly be burning out at 12 V. If you are running at 12V, the head lamp bulbs can be found much easier at most auto parts stores. Good luck. Let us know how you make out.

One other thing, a bad ground is a common cause for bulbs blowing out. But it does sound like you've a little more going on.

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