Project Vespa Smallframe - AC Flasher

 When converting to an alternating current system and eliminating the battery, the original thermal flasher doesn't seem to function very well.  They sell a "AC Flasher" unit, so I bought one.  The duty cycle isn't ideal though.  The turn signals stay ON longer than they go OFF.  I would like to have a little closer to 60% duty cycle rather than about 90%.

 The first thing to do was reverse engineer the circuit to see how it worked.  It seems to be a NPN BJT triggered by R C time constants.  The easiest thing to do is adjust the resistor values to achieve a better duty cycle.

 The base charging resistor is the easiest to change, and will affect the off cycle time.  Raising the value of this resistor from 8.2k to 30k should give a more even duty cycle.

Flasher Circuit simulation in action.

 I like to use the falstad.com/circuit simulator to test before committing to a change.

Here's the import source code for the simulator:

$ 1 0.0000049999999999999996 140.81048482046955 28 5 50 5e-11
t 272 144 320 144 0 1 -2.6125880249882747 0.6749068028310193 80 default
r 320 96 320 48 0 56
d 128 48 192 48 2 default
209 192 192 192 272 0 0.001 4.947513985652805 0.001 1
209 272 176 272 224 0 0.00009999999999999999 1.1314853841190933 0.001 1
r 272 80 272 128 0 8200
181 384 384 384 352 0 925.1509181977179 21 6 0.04 0.04
v 64 128 64 208 0 1 60 6 0 0 0.5
w 192 48 320 48 0
w 320 96 320 128 0
w 272 80 272 48 0
w 192 192 192 48 0
w 272 128 272 144 0
w 272 176 272 144 0
w 128 48 64 48 0
w 64 128 64 48 0
w 64 208 64 432 0
w 192 272 192 320 0
w 352 160 320 160 0
w 272 48 192 48 0
w 352 192 352 160 0
w 272 224 272 320 0
w 192 320 272 320 0
w 64 432 384 432 0
g 560 192 560 224 0 0
178 384 320 384 192 6 1 0.2 -0.021758635421366957 0.05 1000000 0.02 20 0.015 0.005 1
w 352 320 272 320 0
w 384 320 352 320 0
w 400 192 560 192 0
w 384 432 384 464 0
p 480 352 480 416 1 0 0
w 480 352 384 320 0
w 480 416 384 464 0
w 384 352 384 320 0
w 384 384 384 432 0
g 384 464 384 480 0 0
x 453 177 470 180 4 24 C
x 409 314 435 317 4 24 L1
x 82 72 108 75 4 24 L2
w 64 48 64 16 0
w 64 16 368 16 0
w 368 16 368 192 0
o 30 512 0 4098 10 0.1 0 1

Project Vespa Smallframe - Powder Coating Rims

 The rims on the Vespa smallframe were in pretty sad condition.  They were rusted inside and out from years of neglect and being left outdoors.  They were so rusted along the bead area, I had trouble removing the tire from the rim.  If I ever had to swap a tube alongside the road, this had to be repaired.

The rims were easily stripped of rust by media blasting with an aggressive carbide grit, and then simply dressed up to remove the old paint in non-rusted areas with glass beads.  Powder coating is a very good paint which resists fuel and oils, it is perfect for small removable parts of the scooter.

Before

After

Carbide is not good to use on thin sheet metal like the fan shroud.  Glass beads alone were used here to remove the old paint, and layer of rust.

Before

After

Vespa PX LML Stella - Drilled Air Cleaner modification

 The reason I'm writing this one up, is because I had heard about this modification, but it took me a while to find out how to do it.  So borrowing from the tribal knowledge of many who came before me, here it is.

There is a space above the jets on the Spaco / Dell'Orto carb which is covered by the air cleaner.  This casting has a recess in it that is positioned directly over the top of the jets.  By allowing direct flow to the jets with the provided holes, the difference is amazing.  I don't have a dynamometer, but my "standard test hill" is the proof.  I increased one main jet size and was able to take on the test hill with cooler temperatures and 5mph faster than before.  This is the easiest and most beneficial modification to the 2T engine.

With credit to VespaLabs, here's the difference in the original and drilled air cleaner.

This modification altered the jetting :

DR177 and SITO+ Stock 20/20 carb 48/160 idle, 160 air, BE3 atomizer and a 107 main jet. Drilled stock air filter frame stripped and replaced with UNI foam.

Mix Turns = 2.0

Project Vespa Smallframe - Points and Condenser

 Everything was running so well, until the spark became intermittent.  So the points and condenser were the first target of scrutiny.  I never confirmed the ignition timing, the bike started and ran well enough, so I didn't question it.  It turns out it was just set to the nominal marks on the stator, which is not horrible, but just not ideal.  

After a readjustment to the specified 17 degrees BTDC confirmed by a timing light, I set off again.  It wasn't much better.  At that point I ordered a set of points and a condenser.  Immediately upon removing the condenser from the packaging, I tested its value as 225nF (which strangely was the same as the one I took out).

I will keep the original as an emergency spare.  It looks like it was recently replaced anyway.  The erratic nature of the mis-fire led me to believe it was point and condenser related, but I had to rule that out.

After setting the timing up with the strobe light, it does fire nicely at 17 degrees right at idle.  However its still somewhat erratic at higher revs.  I finally removed the ground connection on the stator and re-soldered the joint.  At the same time I ditched the stock condenser and used a 630v rated vacuum tube radio capacitor.  At 330nF it should be close enough.  I also like how well it mounts.

Now that I have the ability to strip the flywheel and re-mount it with my eyes shut, the work went swiftly.  The engine started on the first kick and revs as it should.

Project Vespa Smallframe - Horn Repair

Rehabilitating the horn is actually a pretty easy task. The rivets can be ground off of the back side so that they press out with a flat punch, allowing the unit to be disassembled. I did this with a Dremel cutoff wheel. The inside was really corroded, which prevented any good contact from being made. The two terminal screws can be removed and the mechanism cleaned. The adjustment screw is also removed from the rear side. I suggest running the screw the whole way in first counting the number of turns so that the adjustment can be returned nominally to the original place.

Current flows through contact directly connected to the coil on one side. The other terminal is on the opposite side of a set of contacts. The contacts are normally closed completing the circuit. When the current flows through the coils they act as electromagnets which open the contacts stopping the current flow through. The contacts close again completing the circuit. This cycle repeats as long as voltage is present at the terminals. The adjustment screw adjusts the tone of the horn.

I used a wire wheel to clean the components. The final step was to use some contact cleaner such as CRC 2-26 which is safe for the insulator components. Assembly is the reverse order as disassembly.  

The rivets were made of soft aluminum. I just happened to have a soft aluminum wire (typically used on a residential satellite television dish). This is very malleable and makes good material for rivets. The wire is gripped in a set of pliers and a ball-peen hammer can be used to flatten the end to form the head. The wire is nipped off with a set of cutters to an appropriate length. This makeshift rivet is then inserted into the original hole and pounded flat to secure the horn.

Beep Beep

Vintage ride EDC - Every Day Carry

 I consider my Stella a vintage designed scooter.  She may not have pedigree or be old, but she's the same design as vintage scooters.  Therefore tools are needed.  If not for me, then for my fellow riders benefit.  Don't get me wrong, she's always got me home, but you have to be prepared.

So folks may be interested in what is carried all the time in that massive storage compartment.

#1 Flash Light!  I keep a magnetic mount USB rechargeable LED light.  This is essential, because I do ride in the dark and would not want to fumble around making a repair in the dark.

#2 Wheel Jack.  I made a scooter jack out of some wood.  It doesn't have to be complicated.  Two blocks sit under each side of the center stand feet.  This allows removal of the front wheel.  The cradled jack side can be used under the rear shock absorber to get the rear off the ground.  Sure, you can tip the scooter over in the grass and let the fluids leak out of the tanks, but that's no fun.  It can be propped up against a building, but what if you are in the middle of nowhere?

#3 Hand Tools.  The most important are the tubing spanners and tommy bars, then a set of open-end wrenches.  A 6" Crescent wrench, just in case a bolt needs held while the nut is removed.  A combo screwdriver.  Fourth Hand cable tool, and spare cables with nipples.

I also keep a few inner tube patches, bicycle hand pump, and tire gauge as well.  Flat tires happen.

The point is to be prepared for about anything.  The tool you don't have is the one you need.

Vespa GTS hpe - Turn Signal Beeper

 One lacking feature of the Vespa GTS is a sounder for the turn signals.  Since the turn signals don't self cancel on the scooter, you have to remember to turn them off.  (Gee, my 1979 Yamaha had self-cancelling turn signals, why can't they do that today?)  The only indication the rider gets that the turns signals are on is a little lamp on the instrument cluster.  If I'm watching traffic, I'm not looking at my instrument cluster.  In a busy traffic environment it could be dangerous to leave a turn signal on.  It can also be annoying to fellow riders when you are in a group.  In any case leaving the turn signals on is not accurately representing the rider's intentions.

What I needed was a simple way to add a turn signal beeper.  The one on my Stella is way TOO LOUD, but I never forget to turn it off.  The easiest thing to do was run some wires back from the front turn signal bulb connectors.  This proved much easier than I imagined due to the high quality electrical components that Piaggio uses.  This turns out to be a quick project for a snowy day.

The existing wires are shown with the squiggle at the end back to the existing harness.  I used some diodes out of my junk drawer, but a pair of 1N4001 diodes will work.  They just block the DC electricity from going back to the opposite turn signal.

The diode module on a small piece of perf board.

The white connector housing may be opened by spreading the two tabs, and unlocking the fold-out holder at the wire-side of the connector.  Don't force it or it will break.  Use a needle to gently lift the plastic tab INSIDE the opposite end where the wires come out.  This will release the crimp connector and allow it to pull out.  Your new wire can then be soldered to the back of the crimp connector, and pushed back into the connector housing.  Do this on both sides, and re-assemble the turn signals.

I made an aluminum bracket to hold the buzzer along side the existing USB charging port.

A piggyback connector was used to utilize the negative connector from the USB charge port.  The common side of the diode was connected to the positive terminal of the buzzer.  I shrink-wrapped the diodes in yellow and drew their symbol on the shrink tube, so I remember what's in there years from now.

There you have it!  All done.