Modern Vespa

Vespa rally 200, 1975

Converted by previous owner to 12 volt, non battery, Ducati piaggio flywheel (off a px150/125 looking at the fins)
Piaggio stator plate, rewired about 4 years ago by beedspeed (hardly used since then, less than 100 miles).
Has had new Ducati cdi (the blue one) new HT lead, cap, plug.

Ok that outlines the engine, so my problem is simple, sometimes it starts first kick after being left for a month, sometimes it won't start for love nor money.
It always appears to the same problem, I take off the plug kick over...no spark.
I tinker around for ages, checking leads, changing plugs etc, and then if I'm lucky I kick it over and there's a spark, if I'm unlucky there isn't.

Drove over to my girlfriends today, drove fine, I had to mess around to get it started, but once going it was great, then when I went to leave it wouldn't start ....yes you've guessed it, no spark, no amount of bump starting made any difference, dried different plugs/caps...nothing, then I saw a spark whilst checking the plug, put it back in and momentarily it fired up then instantly died (tried bump start ...nothing!)
Pushed it for about a mile up and down kerbs then just for the hell of it I tried to bump it again and brrrrmmm , it nearly took my arms off, drove me home perfectly (about 2 miles)
So I'm at a loss as to what the problem is
All help advice greatly appreciated

Troy

Try swapping CDIs next and then after that stator time. Looks like you covered everything else.

There can be issues with the alignment of the pick up and flywheel.

I'm going to order another CDI, they're cheap enough, and it's worth having a spare.

Has anyone had a cdi behave in this way, as in work, not work then work perfectly 5 minutes later??

As for the stator they are a mysterious beast.
I've read plenty of posts about stator problems, and yet again could they fail, then work, then fail then work, etc etc etc

It looks like the stator can cause you headaches when they go wrong, I was wondering if the LT coil ( which i believe is mounted on the stator) is playing up.

I won't really know if it's the stator until I exchange it.

From the description I gave of the engine above what would you recommend??
A. Get the stator looked at and repaired, and if so by who??
B. Get a brand new stator, and if so which one, are there good replacements about, I really don't want to mess around with parts that 'don't quite fit'

The abundance of spares out there that are rubbish is shocking.'
I'm about to search for another new stand for mine, I've had two from Beedspeed in two years (RMS ones I believe), absolute junk, they look nice, but they bend out of shape and the bike starts to lean in less than a year, and the rubber feet have worn badly already.
(if anyone has an genuine old stock stand I'd be interested in that too 😺)

I think a problem in the wiring stator to the ground

Are you suggesting a wire that comes from the stator and grounds somewhere, it's a long time since I put that stator back (after it was required) and i don't claim to fully understand the wiring.
I just put it back in the same way it came out (digital camera being a life saver)

A dodgy earth/ground makes sense to me, please excuse my lack of knowledge but what wire am I looking at checking?

Kill wire shorting? Try disconnect from CDI.

Looking at CDI from left to right the colours go
White/ Red/ Green/ Green

Which lead am I disconnecting,

P.S. My Rally is turned off by the key, not a kill switch.
(Although the handlebar light switch does have one on the side, but it doesn't do anything, the switch was made by grabbor, I assumed it was replaced at some point and that was all that was available)
I'm going to go and check this now

Thanks for your reply, actually thanks for everones replies 😺

Ok,
I took a video but couldn't upload it so I'll try to upload a picture.
The wires coming from the stator are all connected to the CDI except the black one, that has a bit of electrical tape over it.
I have no idea what this is meant to connect to, that's the way it was before and after I had it re-wired.
I assume on a PX or what ever scoot it came from this connects to something, but on mine it doesn't.

There's also another wire that comes from the loom that is also not connected to anything, I assume that's from when it was still running the femastronic that I started life as.

The kill button on the side of the light switch on the handle bar does nothing so I assume it's not connected and that the switch is a replacement from some time ago

P.S. It started easily today, no messing about, maybe 2nd or 3rd kick.

[img][/img]

The wire that's connected to one of the green terminals on the CDI and does not come from the stator plate.

Looking at CDI from left to right the colours go
White/ Red/ Green/ Green

Which lead am I disconnecting?


The wire that's connected to one of the green terminals on the CDI and does not come from the stator plate.[/quote]


Ok, I'll disconnect that wire, and assuming it starts again, I'll tape it up, then that removes that out of the equation.

I have suspicions I've tried this before, but this time I won't reconnect it

The black from stator should be grounded.

Really! Ok, well I can do that.

Where is it normally grounded to.
Obviously I must still have an issue because sometimes it starts perfectly as it is, and with my small amount of knowledge I assume if that was the sole problem it wouldn't start at all.

But I'm happy to connect it to something, suggestions most welcome.

I have the black from stator and yellow from CDI under the same fan shroud screwhead.

Much easier to repair something that doesn't work than something that works.

Stator black wire is supposed to ground on the frame, usually at the regulator.

As said already, take off the outside green wire from the CDI and leave it hanging. This is from the ignition key.

Look in the,stator not the cdi
Out of stator blue and black to the regulator
Red blanc and Green to stator at the cdi the last green go to contact
Your problem is in the stator

Ok, I'm going to look at the wiring and try to work out why the black stator wire was never connected to the regulator.
Obviously it can work without being connected but I'd rather it was wired correctly

I'm going to wire it correctly.

I need to get the flywheel off and see if there's any problem with the wiring inside.

Could it be a bad connection after it was rewired.

It has to be something that can work then fail but then work again, and a bad connection would do this, I don't think a component would ...but I'm no electronics expert!

I think a new piaggio stator is about £85, does anyone know if they're any good, or would you have it repaired, I believe there's a chap called Anthony at Scooterlab (??) who repairs and rebuilds stator plates...any thoughts???

Thanks for your help

Looking at the regulator I assume the black cable from the stator is supposed to attach to the blade with the black stick.
From top to bottom there are two yellows, one white, one black.

Do I need to run a cable through?

Looking at the wiring from the engine side the blue wire from the stator connects to a thick yellow wire coming from the loom, I assume this is the thick yellow wire that appears behind the spare wheel and attaches to the regulator.

The thinner green wire from the loom attaches to the outer terminal on the CDI and is indeed to kill the engine, and is fed to the key in the headset (I found this out by disconnecting the cable starting it up and not being able to turn it off at the key)
I know to many of you this is all obvious stuff but I'm still learning, so thank you for your patience.

There is still that mysterious unused THICK green wire that comes from the loom and it's still that...a mystery!

I might do as one of you suggested earlier and ground the stator to same place as the CDI, until I can feed a cable it to the other side.

Checked all the wires again today, scooter was starting well, was about to take the stator out when I decided to go for a ride, half a mile down the road it died.


Used this an opportunity to get readings using a multimeter to test the wires from the stator

Got some good readings then as if by magic ...nothing

Red wire to engine casing 110 ohms (I believe that's about right)
Green wire to engine casing 512 & 568
Green to Red 702 & 669

Then the bike started, and magically died again,
I tried to get a reading without touching anything, and the Red to engine casing now gave a reading that said OL (it wasn't working,
I quickly tried Red to Green and got OL too

Then 30 seconds later I got good readings again.

So the red wire attaches to the pick up coil, when the weekend comes I will remove the stator and check that wire, as I still don't know if its a connection problem, or a fault with the pick-up on the stator

I think I'm getting somewhere



[img][/img][img][/img]

Correct measurements are Red to White (110 ~ 140 Ω) and Green to White (520 ~ 560 Ω). Red goes to pickup coil and Green goes to H.T. coil. White is common ground for both...

So the measurements I got were about right, all the way until the point where I got no measurement at all, although the problems still there, it does point to some issue on the stator plate, which was suggested by MJRally and Choc nc,
so thank you to you both.

I just have to get the flywheel off and have a look

I may have found the problem 😬,
Looking at the wiring on the stator it's a surprise it worked at all.
I can't believe I accepted this work when it came back from Beedspeed, the solder work is shocking, cables never lined up properly with the CDI, I must have been desperate to get back on the road.
Anyway it's in hand now, I will see what happens when this is repaired...properly!

You paid them for this mess?? If you were closer, I would do it for free. This is how it supposed to look...

That's my thought, normally I wouldn't have accepted something like this but as I said maybe I was eager to get back on the road (and off again as it turned out 😬)

Thank you so much for the kind offer, I've found a chap on the internet who builds them from scratch (who I believe will do the job correctly) so I posted it off this morning.
I will post when it's all back in and see what happens

It's hard to solder small wires with a torch.

Picked up my Stator Plate yesterday, rewired with a new pick-up coil, and LT Coil (I think 🤔)
Scootronics who repaired it said there was a problem with the crimping on one of the connectors.
But it's been checked and tested now, so all should be good, Anthony from Scootronics is not only an electronics engineer by trade, but a genuine rally going scooterist too, (and a lovely chap) and he has all the gear and testing equipment to assemble his own custom stators (although at the moment they're for Lambrettas, but I think Vespa ones are in the pipeline). I also bought one of his CDI's as they looked so well made, and have little diagnostics lights on to show that the pickup and coil are working...and I'm a sucker for anything that might help keep my scooter on the road.

Anyway he's done a great job, and I recommend keeping an eye on stuff he's making. The wiring and connectors all look really good.
Hopefully tomorrow afternoon I'll put it back together and see what happens (fingers crossed 🤞🏻)

that looks tasty trojac hope it goes as smooth as it looks!

It's been nearly two weeks since I installed my rewired stator plate, and not one breakdown
I'm so pleased, thanks to everyone for your help and advice.
And thank you to Anthony from Scootronics, who did a great rewire job.

There's still some setting up to be done on the carb, and I need to check the timing but I can go out for a ride now and not have push the thing home...happy days!

8)