Modern Vespa

I installed a brand new P series engine (no battery) in my 65 Vespa VBB. It came with a new 12V AC stator and CDI. Since I completed the installation of the new engine in January I've only been able to get it to start two or three times.

I've determined by using both a spark tester and a spark plug that it doesn't have spark.

Last week I discovered the ohms reading on the pick-up coil was out of spec. It was reading 92 when the specs called for about 110. I replaced the pick-up coil and now have an ohm reading of 112 but, it still doesn't have spark.

The pick-up coil has a pin on the backside that fits into a hole on the plate so I'm pretty very sure I installed and aligned the new one correctly. I also made sure the stator plate was reinstalled to the exact timing mark it was at before removal. Finally, the woodruff key is in its proper location.

Here are the results of the various tests:

White wire to engine (ground): 0.4 ohms

White wire to green: 501 ohms

White wire to red (new pick-up): 112.5 ohms

White wire to green with the engine turned over using a drill: 60 volts AC

White and green wire to a low wattage 12V speedo bulb: bulb lights up when kick-starting

Green and red wire to speedo bulb: bulb lights up when kick-starting

White wire to red: bulb does NOT light up even when the engine is turned over with my drill and there is no indication of any voltage on my multimeter when turning the engine over with my drill.

Are there any more tests I can try to Dx the problem? Do you think I need a new stator?

I've included a picture of the stator.

This Vespa has turned out to be just like a boat.........

Nine times out of 10 it's a bad pick up.

For starters, disconnect everything other than the 3 wires off the stator that go to the CDI. Check for spark/ ignition. Do you get it?

Worry about all the other lighting later.

Yes, this.

The pickup may also be mis-aligned with the flywheel. That can cause intermittent firing, or even no firing, too.

What's the provenance of the motor? Was it ever Known Good/running that you're aware of?

By chance did this motor come direct from India?

Post more pics like the CDI and fly wheel. Do you heave a points flywheel or CDI flywheel? Some CDI's are not compatible with some systems.

+1 for what MJ said. Only connect the 3 wires needed for firing the engine during trouble shooting.

The engine came from India. It is the only place I'm aware of where you can purchase a new engine for a 65 Vespa VBB. The engine came completely assembled with stator and flywheel. The package also included a CDI and voltage regulators both of which I installed.

As requested I've attached photos of the flywheel. It has six magnets - all will hold a 19mm wrench.

Testing has been done with and without the CDI connected and with and without the lighting circuits connected.

The Kill Switch wire is disconnected

On the two or three occasions I got the scooter to start the horn and all lights worked.

Just no spark.

Are there any other test that can be performed on the pick-up coil other than checking the resistance (ohms)?

From first glance everything looks good on the flywheel. Send a pic of your CDI. Is it a blue ducati model? Red BGM? Blue Mitsubhi clone? Something else?

If its anything other than a ducati model, i'd buy a spare and keep it for when the no name brand shits the bed.

Blue Mitsubishi

What is all that scraping on the inside of the FW ?

Starting to grasp as straws a little here but..

1) Any chance you have a Known Good CDI to try? They're cheap enough that's a route I'd go down, even if it'll take a couple days to get to you.

2) The plug wire looks like it's pretty stressed in the photo of the CDI.

Have you tried removing, trimming 4-5mm off the end and re-screwing it in? The plug wire might be damaged or pulled loose.

3) Confirm that the pickup aligns with the firing mark in the flywheel. If the pickup is too high (farther away from the engine case) or too low (close to the engine case) it can prevent a good signal.

I've made the mistake of having one point of the stator not quite sit in the groove for the mounting screw and that was enough to cause it to not fire. Also, that caused the sort of rubbing on the flywheel that you seem to have.

That flywheel has seen some days, though, so the rubbing could be a from a previous motor.

THIS!!

A few things to add. Is your plug wire copper core or some sore of fiberglass looking core? Should be copper core.

I am willing to bet #3 above is the true issue. It looks like you need add a spacer behind your stator to jam the pickup deeper inside the flywheel. Your hall sensor is trying to find the where the 2 magnets overlap on your flywheel (on your picture it is shown in the 6 o'clock position).

As for rubbing, it happens. My new Italian flywheel rubbed when I first got it. I adjusted the pickup as much as I could but it still rubbed a little. I used cleaner to get rid of the yellow coat, then lightly sanded all around to get the last bit of clearance needed. Retrospectively maybe I should have just made the hall sensor attachment hole larger so I could scoot it in more.

I will attach a picture to show where my pickup was rubbing before I massaged the clearance. You can see the pickup is much deeper in the flywheel compared to yours.

+1 for MJ. Buy a spare Ducati Blue CDI from a reputable source. They are not expensive and have been proven very reliable.

I asked if it was an Indian motor for 2 reasons. 1) Wanted to know if you found a non-Indian source for P motors for selfish reasons. 2) Put everyone on the same page. In my opinion parts direct from India are of less quality and have more fit and finish issues. I have bought some direct before and regretted it (thought I was getting a "good" deal). That said, I do have parts made in India on my bike. However I bought them through a reputable dealer here in the states. My experience is that the dealer buys a higher grade of part (it doesn't benefit them if their customers start kicking a bunch of parts back).

If I had an LML motor such as yours, I would double check everything. I would make sure all case bolts are torqued, head bolts are torqued, put a NGK spark plug in, make sure carb box and carb are on well, and verify carb jetting. Then I would pressure test your motor when you get a chance (this is a must in my mind for any new engine regardless of where it came from).

With LML shutdown and out of business for 4 years, where are these new motors coming from? I can't believe there were that many motors lying around with frames still being sold new in crate. Could these be parts that are out of tolerance and being sold as new?

The new motor was manufactured in India. Obviously I haven't torn into the internals but it appears to be well built and the fit and finish is very good.

Ok back to the No Spark issue.

I have tried 3 different spark plug wires.

I removed the flywheel just to confirm the new pick-up coil hadn't moved. There is virtually no way to misalign it given the tight tolerance of the hole for the mounting screw and the stud on the back of it that fits into the stator plate.

What little I know about the electrical components on the scooter I learned on this forum.

In layman terms this is what I think should happen. The stator/flywheel creates electricity that is sent to the CDI. The CDI boosts the voltage and sends it to the spark plug based on impulses from the pickup coil.

If my description is correct how can I measure the voltage out of the stator to the CDI? What value should I be looking for keeping in mind I have to turn it over with a drill motor or the kick starter?

Should the pickup coil or any of the other coils actually rub against the flywheel?
If not what is the ideal gap tolerance?

I appreciate everyone hanging in there with me.

You've got the ignition theory correct. Unfortunately I dont know what the voltage is coming out of the green wire to charge the CDI. It happens so fast (16 times/ second)/ 1000 rpms. You can try this test to see if the pickup is aligned with the flywheel magnets.

I performed the Play Dough Test as shown in the video. I'm sure the pick-up coil is sitting where it should depth wise - not to deep or to shallow.

I'm not so sure about the left to right sitting. I performed this test a number of times and each yielded similar results. I've included the best picture of the lot.

The stator is lined up to the exact same timing mark it was aligned to before I remove it to replace the pick-up coil.

Based on a review of the before and after photos of the pick-up coil the placement looks look identical.

Since the pickup measures out ok, pickup depth looks ok and youre reading voltage from the green wire, I'd lean towards CDI. How close are you to getting a replacement?

just to cover your bases, change out the plug cap (or test it for resistance).

I'll put my money on that Mitsubishi CDI. They have a known history of being bad out the box. I have a bad one out of the box and a spare good one in the cabinet now. Get a Ducati CDI.

Good luck!

Those have nothing to do with Mitsubishi. Piaggio uses Mitsuba, Ducati, Mitsuboshi, and other known suppliers. It's just some Indian crap CDI with a name that resembles Mitsubishi for people to think it's a good quality CDI...

Time for another update.

All those that recommended I replace the Mitsubhi (not Mitsubishi) CDI were correct. I replaced it with a Ducati CDI and got spark but, I continued to have problems getting it started. I adjusted and readjusted the timing. I think I finally got it dialed in.

It was fouling the spark plug after only a few minutes of run time. I leaned out the fuel mixture the last time I had it running and was very please with the way the engine sounded and responded to the throttle.

Unfortunately, all of the attempts to get it started apparently screwed up something related to the kick starter and the engine is now sitting on my bench apart.

Watch for a new thread related to the kick starter.

I am exactly going through the whole thing times two P series engine. They went from running to not running. I was replacing the kick starter gear and I had to pull half of the engine case(major PITA). Got it all together and no spark. I had spark initially but not anymore. I have lots of spares laying arounds(CDIs, flywheels,sparkplug wires, spark plugs, stators).
For the first time in a long time I truly got my butt kicked as far is t-shooting. I ohm cheched everything green to white (512ohm), white to red 112 ohms. I don't know what else to do.

I have a P200E that starts on the second kick, it is my last source to test a good working Ducati CDI with a good working sparkplug wire. During the process of replacing the kick start gear I noticed that the stator coils rivets were all lose and they are rubbing against the flywheel, chances are that the sensors on the flywheel got damaged but ironically the engine used to start quick before I replaced the kick start gear.

I am at square one with absolutely no plan B for T-shooting, if anything I am going to order a brand new ignition system from one of the big companies(pinasco, Polini, Malossi vespatronics, SIP , BGM or whatever is out there that looks worth it.

If you find out anything please write an update, I am at the same exact sport as you were.

Evening chaps, my scooter starts to splutter when I open it up to 60. Not all the time but it's done it about 3 times in the last couple of months. Someone suggest that maybe my pick up is on the way out.is this possible?

Been going through the same thing. Start/no start…This is a very helpful Thread.

Only happens during high speed sounds like fuel delivery. I'll start there but check the ignition grounds cuz when the ground screws are loose you get the same symptoms during high speeds.

I was getting the high speed bogging before the no start. I am running a P200e engine in a Stella with a Stella Stator and P flywheel. The P and Stella stators obviously have different wiring for battery and lights but look identical in terms of dimensions. Looking at them more closely, the pickup on the P Stator actually sits 3-4 mm higher compared with the LML. Hmmm…

I installed the P Stator and hooked up the 3 wires to the CDI. We'll see if it starts now.

I bet this happens fairly often when mixing and matching flywheels and stators that were manufactured decades apart, from different models, etc.