Modern Vespa

Should have the 140AC shortly. It's on its way. While I waited I dug into the no lights or horn issue. Redid all ground points. Sanded to bare metal to make sure.
Vape regulator is attached to bare metal with screw used to attach it to the frame. I don't have a ground to the metal housing of the regulator, do I need one there? Not sure if just the housing to bare frame is enough?
Tail light is grounded under the tank to bare metal.
CDI is grounded to the bracket and the engine case.
Ground for the headset is grounded to the throttle tube attachment screw.

Checked all wires for continuity, ALL except the purple wire below has continuity with ground. Green kill wire has no continuity with ground or any other wires. Purple has no continuity with anything, including itself between the switch and headlight.
Both BLUE wires at the regulator have continuity with ground as well.

All was running fine when I put her away for the winter in the lighting department anyways. When I woke her up nothing worked, no lights no horn. Kill works though.

What could the issue be? Fried regulator? (Not sure if the Vape connections are specific to which blue wires in the harness connect to them, ie one blue as the input and the 3 blue output connection). doubt it's the CDI since I have spark and the engine runs.

Any ideas or where to go from here?
Thank you!

After all that the lights mysteriously work now. No clue why but I'll go with it.

With lights finally I was able to get out and work on jetting/seating the rings and such.

20.20 carb
Started with 55/160 2.5 turns out
Undrilled blue filter
140/BE5/126

Whole throttle range was spluttery. So started walking down the main jet. Got down to 115 and still spluttery up top down low and in the middle. Didn't feel too good going lower on the main so tried the mid range. Walked the BE5 down to the BE3. Still spluttery but a bit better.
Maybe with this sound recording you guys can help me out…

Are you running a 24/24?

Here is the jetting I did for B62. Still a slight stutter down low, and it takes a few to warm up, but I can WOT without going over 300f, which is the main way I've been running it...

20.20 sorry forgot to put that in there.

Alright, after fixing the selector box pin that decided to jump right on out, I went for a ride. 20 miles or so of varying throttle positions. Doing some tweaks here and there and I gotta say right now I'm pretty friggin happy with where I'm at. No choppiness coming off idle. Just a slight one in the mid range. Runs way better than the VMC does currently. I'll get back to that if I ever get my order from Mercato.

Jetting is as follows
Drilled filter from the 24.24 si
160/BE3/110
40/130 3 turns out on the mix screw.
Max temp of 211°
Didn't stay at WOT for very long maybe 10 seconds.

She's got 6 heat cycles on her and a tank of gas has been used. I probably should have started with the 3% gas mix but I forgot and have just been rocking it at 2% during the running in. I dunno if that's the worst thing ever. Seems to be going fine as is though. Letting off the throttle is silence. Something the VMC has yet to accomplish.

I'm pretty stoked on how it's going so far.

Glad it's going well. I have a Stella engine I was planning to put in my '62 VBB, but may rebuild the original instead. It came with a 2 port VBC engine that was still running and the original case which was rusted solid. The VBC guts are all good. I cleaned up the original case and had it welded. I liked the way the VBC engine sounded. Would go good with the Pinasco kit.

The Pinasco has just enough umph to be fun but not ridiculous like the VMC. I'm liking it. Two different rides, one for touring and one for the city. Just gotta dial the VMC in now.

To not hijack sdjohn's thread I'll post this up over here as well.

So close…

Max rpm was 6810. Max temp 265°.
Pinasco 2 port plug and play.
Sip road 2 exhaust, 24.24 drilled filter.
Vape ignition 18°
160/BE1/112
40/130 idle 3.75 turns out. Still a little choppy at the start of the throttle. Have 2 richer jets on the way.

Chandler- I have not tried a lower main, the 112 seemed to be the first on the walk down to be clean. I can try that tomorrow though. Plug looks ok to me maybe a little rich too like your thinking.

I'm looking at your temp and thinking that if you only got to 265, then it's not running hot enough, which says too rich at WOT. Not by a lot, but just that one jet.

The other thing you could do is leave the main at 112 and remove the air filter, just run it bellows to frame. I just tested this on my Lammy and adding a pod filter dropped the max RPM's on the stand by 600. I've had similar experiences with other bikes in the past.

I'm rooting for your plaid status all the way!

Thanks man! It's a wild attempt on 8" wheels and the pogo spring fork. The stoffi spring makes it a bit less sketchy at least, still sketchy though.

I'll have a chance to try both tomorrow. I am a little surprised at the low temps. I didn't WOT for too long. I'll do a test of that first as well, a longer WOT run. See what it settles at.

Haven't had time to test out jetting, been busy but have taken some rides.

When cold and I start the bike the first shift into 1st my bike lunges then dies. Kicks back over easily and doesn't do it again. Why would it do that?

I will say the Pinasco 2 port is possibly perfect. Enough oomph to get you going but not an obnoxious amount of speed. I'm a fan. This bike rides pretty well. Just gotta sort out the jetting. A story as old as time.

above you said you timed for 18 degrees - is that what the kit instructions say? for some reason I was under the impression that the kit stayed with 22 degrees.

I timed mine at 18. 22 would be for points, I think.

If you have a better piston lying around, i.e. something with 1mm rings, I'd use that instead of the stock one, too.

I installed a Vape and their instructions call for 18°. I'm not sure I saw a timing suggestion in the Pinasco paperwork, I may not have even looked since the ignition wanted 18° though

Was out the other day riding and trying to get rid of the low throttle choppiness. Nothing helped. Mix screw in and it's too lean causing the revs to hang and out it's too rich fouling the plug. No middle ground. So I tried to pop in a 150 AC just to see what effect that would have.
Got the bike started fine and it was a Smokey bastard. It eventually stalled when I gave it some gas. Well that was worse than the 160AC so I popped that back in to go ride and put in a new plug just to be safe. And now I have no spark I think. It was daytime so I tried to check the plug by grounding it to the frame and kick it over and saw no spark. Will try again when it's dark out to be sure.

Probably need a new cdi? I dunno. I did open the junction box and saw a wire was a little split and touching the other wire so I moved them apart and tried again but still had no spark.


Edit: just went out and made a make shift sun blocker to check for spark. Nada

For the spark, I'd start by confirming you don't have other rubbing spots in your ignition wiring, including down at the stator.

For the carb, do a pressure test. It sounds like you're trying to jet around an air leak.

Almost a year later. With Bears' engine on the stand it's Bluey's turn to get some Vitamin D.

Over in the Vespas that have made it outside thread I mentioned 4 stroking at 1/4 throttle. Went from BE1 to BE3 and still getting the machine gunning. When if is doing it I do the pull the choke test and it gets way worse. Similar if I pull the choke at a stop light the bike goes to sleep. Starts right back up but I think that means the idle is too rich too?

Currently have:

55/160 1 1/16 turns out on the mix screw
160/BE3/108
20.20 carb with 24.24 air filter
Vape ignition 18°
Sip road 2

Have the idle set around 1400 (led bulb) and when I get to a light the idle drops down quick the rises to 1550-1600 and stays there. I'm sure that should also be telling me something. But I don't speak carburetor. So can someone translate that for me please?

Idle rises makes me think of an air leak.

This is now what, 2 years you are struggling with jetting ?! This is crazy !!
Hope you will finally set that thing up and enjoy riding !!

You'd think but I keep going leaner and it gets better. Which is counter to chasing the air leak. It's been leak tested multiple times. Even the plug is rich. It's just baffling. I saw a video on YouTube explaining that when you drop back to idle and it drops below where you set it then rises back up that was a rich issue. I can do another air leak test though just to be sure again.

Wait for an expert advice, I'm no specialist in jetting.

I imagine when you pressure test you remove the carb, but the leak could be in between the block and the carb which won't be revealed by the pressure test.

To avoid that kind of thing, I lay a sheet of 400 grit paper on a flat surface (glass works well, or marble top), I spray some wd40 as lubricant, I put the carb body flat and make 8 movements for a minute, then I inspect closely the sanding marks left on the surface and do again until it is uniform. I do the same with the carb box base.

I put a very light skim of gasket maker (Dirko HT) on each side of both gaskets (under and over the box) before assembly. For sure you won't get any leak from the carb.

(I also use the same technique for the cylinder head, even new they are rarely 100% flat)

Do you have a 50/160 to try next?
The 20/20 Pinasco jet kit for their 2 port 177 has a 148/160, BE3, 160ac.
105-115mj(?). Can't find it now

If you're setting idle speed while cold and rpm increases at operating temperature closed throttle that implies lean.
But closed throttle is mixture screw.
With a too rich pilot jet you can still have lean idle at a stop if the screw is turned in too much, like to compensate for a too rich pilot jet four stroking like crazy at barely open throttle.
It's influence as a flow limiter tapers off quickly as you open the throttle, so at 1/4 the pilot circuit is then too rich.

Btw all my bikes will want to go to sleep if the choke is pulled at a stop while hot.

I don't have a 50/160 but did have a 45/140 and the 4 stroking it mostly gone. Was riding today just cruising at 1/4-1/2 throttle and man she's smooth running.


45/140
160/BE3/108
Temps never went above 220°

Well this is a new one….

Still isn't perfect but she's close. With the low throttle 4 stroking I decided to run a WOT main jet test just to check. Figured maybe was still one jet too rich and maybe it was bleeding into the low circuit.

I think the main is spot on. Plug pic below. What do yous dudes and dudettes think?

Good things are happening with your main. Color is well safe. Pilot lolls rich but hard to tell.

Four stroking/ reading your scooot's tune:

I think it's helpful to think of it as "tune for load condition". These motors have different demands under load then not. So u can't tune for both. U just have to aim to split the difference to your liking.

Here's the analogy I can best think of.
If you were riding your ten speed on your street, and you stopped pedaling, you would hear the sound of the rear hub coasting. Think of that as the four strike sound.

If you peddle, it goes away. Because it doesn't freewheel under load.

But right at that transition, if you lazily peddle, and have some momentum, it will break into a coast from time to time.

That's how u wanna tune your scoot.
If it's 4 stroking under load - that's too rich.
If it's four stroking when you have momentum and crack the throttle, that's okay because there is no load to use up the fuel.

So WHEN is it four stroking is the question u should focus on when tuning. It SHOULDN'T do it as you leave the line because you are putting it under load from a dead stop. It SHOULD if you have a little momentum rolling along and crack the throttle.

Not sure if helpful, but bottom line is, define or record what the load condition is when it's four stroking on cracked throttle. That will expose how your idle jet is. It's not if it four strokes, it's when.

Currently it four strokes under load and when I have momentum. Tested both today. When heat soaked, the four stroking was slightly less in 3rd when cruising. Was limited to the first opening of the slide. Like 1/8th throttle. 1/4 and just under that was okay. A teenie bit of splutter. She's getting there. If I hold the throttle barely open under load the four stroking starts to clean up around 3500rpm.

Had the mix screw 1.75 turns out and the rpm's drop immediately. Turned the screw in and they started to hang at 1550for a bit before dropping back down to 1350-1400 where it's set. Not much of a hang I guess. I think that tends to mean the idle sits at like 2200 for a bit then drops down?

Currently have a 55/160 in there. 160/BE3/108, drilled 24.24 filter and sip road 2 box and a 7 spark plug.
I should have time to do another plug chop. I did a half throttle one today. 1.5 miles slightly up hill (3% grade) WOT in 2nd because for the first time ever no one at all was in front of me on this road. Figured I'd give the half throttle a check.
Tomorrow if I have time I'll do a 1/4 throttle check and maybe a just barely cracked. Even know I know it's rich, if I pull the choke it gets way worse.

Maybe going back to that 3.11 idle jet is in order.

Had to run to CVS to grab some prescriptions and had some time to fiddle on the way there and back.
Started with the same jetting as yesterday
55/160 2turns out, 160/BE3/108

Once she got good and toasty with temps over 220° I decided to go to a 45/140 idle jet. Barely any sputter. Only when I'm changing gears whilst moving. Under load it disappears and I can actually hold the throttle open 1/4 or a little less with no spluttering.

Spark plug at home after a bunch of lights and idling below.

Since Bear was having issues I took Bluey out today to the grocery store.

Zero complaints. Running dang near perfectly with this set up:


24.24 filter with drilled hole.
Sip Road 2
Number 7 slide
45/120 1.75 turns out.
160/BE3/108

No decel popping. Only four strokes just when the throttle is cracked open.

Do you have a CHT on the spark plug? If so, what's the temp at WOT?

I'm asking cause I run mainly WOT and cannot keep the temp below 300F without a much larger main jet.

I'm rarely at WOT. I did a main jet test and it was still a little dark. Max temp has been 247° while cruising at 1/4-1/2 throttle for a few miles.
I'll take a main jet plug pic next time. I'm also leaner on the idle. Going that way with my other bike as well.