Modern Vespa

That is actualyl part of the debate. Lol. I for one am a believer in overkill.

Felt collar is installed per Scootermarc69's advice. Given that the intake housing is covered in slits and the actual seal is at the end of the intake tube anyway, I just don't see what a felt ring would accomplish there, whereas a felt ring makes sense as a dust/dirt seal at junction of the housing/intake.

New Bitubo (longer) shock bolt and a few sundries should arrive today. Got the fork in last night (will post photos). On to wiring!

Really really nice. I miss mine. Spunky ass little 125. Mine was a daily rider to work at 5am and never let me down.

I can't wait to get mine on the road. Weather, and bum foot permitting, I hope to be painting next weekend.

Post photos!!

Definitely.

Hi, great thread.

I hope there will be a video of your engine running, must be getting close.

Been swamped at work and have a head cold too -- both have slowed me down, but I am getting close. Another update coming tonight.

Definitely planning on a video for the first attempt at startup!

In goes the top steering bearing. Made sure to use the collar with the ridge down against the bearing:



Connecting the switch was a little confusing at first, as none of the wires matched what I had. Used this wiring diagram to work it all out:

http://www.scooterhelp.com/electrics/wiring/VMB1T.pdf

Initial confusion:



Switch & headset back on:



Routed, but have not connected the clutch and front brake cables. More photos to follow soon!

Last edited by nomadwarmachine on Mon, 04 Mar 2013 06:34:35 +0000; edited 1 time

Does anybody know if CDIs crap out in ET3s? I have everything back together (pictures to follow), but not spark.

Hey bro... I'm pretty sure any CDI can take a dump.. can you borrow a wokring one to check? Plug wire good? Both ends? Is the CDI grounded to the case? (if an ET3 CDI needs to be grounded like a P/Px that is). just ideas..

CDI grounded to the case on the studs in the glove box. New plug wire and NGK cap.

Do you know if anything at the switch affects the ignition? The old switch is a little crappy, but looks serviceable. From what I understand, it should make no difference how the handset switches are connected - bike should still run.

Wire harness is brand new, and the stator was rewired. All this points to the CDI in my view. Anybody have a routine for checking with the multimeter?

Update! Good and bad news. Got the bike back together, but dealing with a complete lack of spark. First things first.

Disassembled and rebuilt the carburetor with a Dell'Orto kit:



All back together, with the air filter attached (was going to go with a larger 24mm carb, but I want to hear the bike run before I start upgrading):



Carb installed on the intake:



And the fuel tank is installed, along with the "tool tray":



Clean rear wheel ready to be installed:



Muffler attached to the header:



I thought it was strange that the harness had such large "loop" connctors, but everything matched uo, so I did not worry about itL



Had some extra length on the black/blue wires from the harness. Will have to tie those off:



Stopped by a beauty supply store to pick up some bottles for the oil. So much easier to do it this way than with rolled-up magazine stock:



Cleaned up the front wheel as best I could. The bike had been covered outside, except for the front wheel, which had a good deal of rust. Put is all back together and cabled the front brake (MUCH easier than on a P200):



All back together!



And here is my attempt to start -- gas leaked everywhere because my fuel line was too large. Changed that but it still would not start:

http://youtu.be/ULfiECAfJxo

Epilogue: NO SPARK. Questions for today:

(1) Does the handset control box have anything to do with the ignition? I don't think so, but I want to isolate the issue.

(2) How can I check if the CDI is functional? I have a new harness, rewired stator/pickup, and a new coil/cap. In short, everything is fresh except the CDI. Is it common for these to crap out?

Thanks!! Almost there!

Last edited by nomadwarmachine on Mon, 04 Mar 2013 09:12:57 +0000; edited 1 time

I wish I had your skills

Looking at this diagram
http://www.scooterhelp.com/electrics/wiring/VMB1T.pdf
the first thing I would do is disconnect the green wire from the cdi. Specifically the green that goes to the key switch.
If that doesn't do it I would confirm that the red wires from the stator haven't been reversed.

I tried disconnecting just the green wire (with the red marking) last night and still nothing.

I do not see how the red wires from the stator could be switched, as they are different lengths and have different connectors (see my earlier photo -- one has loops and the other is a socket connector).

u did good mate and i am sure u will fix the electric problem soon

The bike is running! I pulled the red/green wire from the ignition unit and relocated the red wire in the handlebar switch to a ground. Nothing happened. But then I had a flipped the ignition switch so that it faced in the other direction, and this happened:

http://www.youtube.com/watch?feature=player_embedded&v=P1SN8d9G_ig

Starts right up. However, as you can see, I have no headlight (tailight works just fine). Can anybody with a Prima or ET3 shoot me a photo or tell me how these are wired up? I feel like I have tried everything.

Also getting a small leak out of the carb through the cap where the fuel enters. Looks like there should be an O-ring or gasket around the housing over the fuel filter, but there was none in my rebuild kit.

Here is a photo of the type of connector I have on my headlight. There are four connections and I have four wires that plug in.



Question #1: where does the ground go? It obviously does not go at the bottom, but does is plug into tab 1, 2, or 3 moving from left to right (see the red numbers on the photo)?

Question #2: where do the other colors plug in? I think there is violet, pink, and brown. Ground is most important, but I would appreciate knowing the correct positions for the others too.

Hope this helps.

From the beedspeed pic:

1. Purple
2. Black (ground)
3. Brown
4. Red(positive)/Blue (speedo light)

Awesome, thanks!!! Any chance I could get a similar photo of the handset switch wiring too?

Ok, just came back from the garage...

You are a hero. Thank you!!!!

I love this thread. You are having and solving every problem I am concerned with on my upcoming reassembly. Soon but not soon enough.

Bike runs well and I recently got my speedo back from Steve at SpeedoKing so I now can know how fast I am going!

The one lingering problem I have is the following: I blow headlight bulbs constantly. The light will come on when the bike is idling, but if I go for a ride, both of the headlight bulbs are shot when I return. Taillight is perfectly fine.

What can I do? I think I have to reinstall that regulator that was bolted to my bike before, but how does it attach? (It had a yellow wire and a ground). Any help appreciated, as the bulb issue is keeping me from riding past dark.

Thanks!!

Sounds like a short. The filaments on those bulbs are large so they are like a slowburn fuse when there is a short. They can handle the lower current at idle but heat up quick after running.

I'd check inside the headset first. there are a lot of wires in there and metal to short against if they get crossed or rub. You also may have a pinched wire in the steering column or worse a wire got stripped when you pulled your harness through. Hopefully it's in the headset.

Good diagnosis. I was very very careful about pulling the harness through, so I would be surprised if anything was stripped there. Will look around inside the headset.

Rode it into work for the first time today. Not uneventful. Stalled out at a couple of spots. I think that it is seriously overjetted.

What do people recommend jet-wise for a 19/19 (stock) Dell'Orto on a Polini top end + exhaust? I would not think this would be far off of stock.

Take a look at your handlebar switch and headset, check for any areas grounding out. Fully seat wires home in the locating holes in the switch and tin them up with solder if you have an iron. I'm not sure if it makes a difference but my mounting screw has a plastic washer between the switch and the hole. Hopefully nothing is funky with the switch.

I would also look and make sure grounds are clean and secure. I remember two mounting points for the grounds: main ground is to the inside frame and is the area where the CDI bolts up to. The other is in the headset on the metal plate that is on top of gear/clutch/throttle cable guide.

Take another look at your junction box and check if any areas are touching, in your picture the red and black are very close to each other. Maybe dremel the outside ring to give clearance.

Another thing to look for is make sure all bulbs are 6 volts and that your headlight parking bulb and tail light are the same (6V 5W). Don't forget about the speedo bulb too, being a balanced circuit every bulb is important.

I don't have a mutli-meter to measure output of stator, maybe someone else can help out on this.
____________

As for jetting, it's good your on the fat side of the spectrum. What are using for the main and idle?

My guess is start at 90 on the main and 45 on idle, work up or down according to how it feels and check that spark plug after some runs. Dial in your mixture screw. I think your ports have been opened up a bit, how about your air filter-stock? Or has it been drilled with some of the steel gauze removed? Good luck nomad.

Update on the ET3. Motor starts up on the first-kick, runs well, but tends to stick in the high RPMs and then gradually settle down to idle. Possibly an air leak? Plug is a nice chocolate brown on a new 78 main, so I think I am good there for the time being.

More importantly, I have a slow but steady oil leak out of the bottom of the clutch cover. I already pulled apart the cover, replaced the lower needle bearing and the clutch arm (old one was scratched badly). I did NOT replace the O-ring, which looked fine. Still have the leak.

Obviously, I am now going to replace the O-ring. Is there an oversize available that I should use instead? The original one looks a little flimsy and the leak is steady enough to cover the rear rim in oil after a few miles. Has anybody else had this problem?

Yup hanging revs sounds like an air leak, probable culprit is the intake sleeve and carb union (been there). I would also look at the intake to the engine case union, spray some carb cleaner when running to isolate the leak. This could also bring up the debate about the felt washer, I use mine right after the carb and also seal up the slits on the sleeve with hylomar. Double check your mixture screw setting and flywheel seal too.

In reference to your clutch arm leak, I had the same problem after my rebuild when I neglected to change the o-ring. I double checked to make sure it was not the seal on the back plate or the paper gasket. I went to pep boys and looked for an o ring but could only get the size if I bought a kit with assorted sizes. I ended up with one that has a slightly larger diameter but thicker width and it did the trick.

On a side note, your clutch arm and cover are a later version with bearings. My version has only an o ring and just drops in place after you remove the stubborn roll pin from the lever.

Really, really great thread! Great documentation and photos. I'm right behind you with a VMA1. Engine running on stand, body work in progress.

Scootermarc mentioned the limiter hookup previously, I think.

The AC voltage limiter yellow wire needs to be "T" connected (in parallel) to the yellow wire that goes from the stator to the light switch somewhere. You will have to be inventive. The wire can be REALLY small, as it carries very little current. Carefully removing a small amount of insulation, curling around, then soldering, then taping or coating is one method.

Attach the other limiter wire to ground somehow. That should protect your headlamp.

This thread is amazing! 8)

I was already pretty sure I wanted a smallie, now I'm positive!

Thanks for the effort on pics and write-up. It takes a lot of work and it's definitely appreciated.

Cheers,
John

Bike runs great, nice chocolate brown plug color, but I have developed a slow stream of leaking gunk on the sides of the cases -- looks like the base gasket. I had sprayed copper onto the base before fitting the barrel, but now it looks like I need to pull the barrel and sand the surfaces a little.

Anybody do this with the crank installed? I do NOT want to split the cases just to address a slow leak from the base gasket.

I used hylomar blue on the cylinder head, the cylinder base gasket, intake and on the carb sleeve slits for my rebuild and copper rtv on the exhaust stub. It held up for my break in period but I developed an air leak at the carb union and my intake manifold was leaking a bit at the engine case. I ended up going to a Honda dealer and picked up some Hondabond HT (I hear it's the same stuff as Threebond) and resealed all guilty suspects. Look ma no leaks, the hondabond stuff is great but it does take time for it to set and looks like it will be chore to clean.

Since your planning to lower your engine, pick up some hondabond HT and a new base gasket (maybe the intake too if you want to seal it up). Clean as much gunk before you remove the cylinder. Pull the barrel and stuff a clean rag in the crankcase mouth and carefully clean the engine case with some acetone or brake cleaner (a shop vac can help suck up the little bits). Not necessary, but I would remove the cylinder studs so I could clean the mating surface all around. If the piston gets in the way, I would remove it but that's your call. I would not sand the crankcase mouth, too much risk of getting grit inside your newly rebuilt lump

For re-install, skim a thin coat of hondabond on the mating surfaces with a popsicle stick (I also smeared a tiny bit on the gasket paper too- I dunno if this is needed). Don't go overboard because you can partially block the transfers up. Give it a minute or two to tack up (heck it will take you at least this time just to fit the piston rings back in the jug ). I would use new hardware (at least split rings) for the head nuts and torque down to specs. Run a couple heat cycles and re-torque the head.

Oh yeah, the instructions says 15-16 hrs to cure and 3 days to fully set. Good luck.

Well, I figured out the air leak. DO NOT OVERTIGHTEN THE CARB RING! I snapped one of the leaves off of the carb body.

Anybody have a Dell Orto 19/19 that they want to sell?

Fixed it. JB Weld is a wonderful thing.

Ha good stuff JB weld, glad you got it sorted out. This incident would have given me an excuse to fit a larger carb for the kitted scoot, nomadwarmachine soldiers on.

Finally snapped the intake tab on the 19/19 stock carb again. Time to replace it. What do you recommend for a 1976 ET3 with a Polini 135 kit and a Polini pipe?

Not looking for a screamer, but would like some decent power. Happy to go with another 19/19/ DO stocker, if that makes the most sense.

Thanks!!!

Thread resurrection...

Hey Nomad, did you solve the blown bulb problem?
Are you using a regulator?

I just finished a rebuild on my scoot and slapped on a lightened flywheel and a cast iron Polini kit with the new style cylinder head. This setup has higher revs than stock and I too was blowing bulbs (main beam and soon to follow brake lamp). I thought my connections were off so I went thru them and cleaned up any areas of possible concerns. Well, new bulbs in and dammit same problem!

Hmm, a 6volt regulator is a path I did not want to go down but I'm gunna try higher wattage bulbs first. Well I'm happy to say it worked and more importantly at top revs where the AC system outputs the most juice 8)!

I still use all 6volt bulbs:

main lamp - 6V 35/35 watt (ba20d style) *higher wattage
pilot - 6V 5 watt (ba15s style) *stock wattage
speedo - 6V 0.6 watt (festoon) *stock wattage
tail lamp - 6V 5 watt (festoon) *stock wattage
brake lamp - 6V 15 watt (ba15s style) *higher wattage

All the bulbs were purchased from Treatland. Great service, quick shipping and affordable prices.
I suggest buying a pair of each: main and brake bulbs. I also picked up a 6 Volt 21 watt bulb just in case the 15 watt couldn't handle the output but it was not needed.

All my electrics work, the main and tail lamps flickers a bit at idle but nothing really different to stock. The nice thing is that the main beam is brighter and throws more light which is a bonus at night.

Still blowing bulbs, but this is excellent advice. Thank you!! Please post pictures of your scoot!