Scooterotica

The engine needs to be earthed to the frame or else you're relying on the CDI earth wire via the white from the stator, the connections via the loom to earth or possibly the control cables.

You should test the resistance between the green, red and white from my the stator to earth. Green should be >450 ohms, red > 95 ohms, white should be continuous - all assuming your stator is wired conventionally. You should get the same readings between the green wire and the white wire and the red wire and the white wire.

I'd suspect the green will earth or have a very low value.

rosscla wrote:
You should test the resistance between the green, red and white from my the stator to earth. Green should be >450 ohms, red > 95 ohms, white should be continuous - all assuming your stator is wired conventionally. You should get the same readings between the green wire and the white wire and the red wire and the white wire.

Just tested it now, and that is exactly what I get.

rosscla wrote: The engine needs to be earthed to the frame or else you're relying on the CDI earth wire via the white from the stator, the connections via the loom to earth or possibly the control cables.

As i get the readings as described, should I still create an earth from engine to frame, I might as well, where is a good point to create one?

I'm a bugger for earths I tend to daisy chain things like rear light to the CDI mount, CDI to regulator and frame. I don't have the standard mag housing to frame on my bikes. So yes I'm relying on the white. I am running full DC so the other end of my lighting coils are earthed at the Wassel and again at the battery. Easy to add the extra earth from the mag housing it won't do any harm. Check the Earth on the CDI though I have had them work with that missing or the CDI hanging free.
You did say it all worked before the engine swap so check the meter readings on each wire as above. Check all the connections on the stator. A dry joint or a break on your trigger or low voltage coil will stop it. I have a spare stator if you need it to test. Swap the CDI first with the one of the Lou. Easy first.

I've created the engine to frame earth. Checked all the wires and connectors for signs of damage.

Looks like I am not far off having to swap out parts

Nothing is easy, even getting to the CDI on my Lui is a pain - you remember I buried it under the rear mudguard which means engine on stand, remove exhaust, take off mudguard and get my mounting bracket out of the frame.. ho hum. I wonder if my local friend has a spare.. :twisted, thanks for offer of borrowing stator..

What's a dry joint and how do I identify one?

Swapped the cdi put with a new one - no joy. Going to try swapping the HT lead although I can't see why one should fail - although I guess it could be easier just cutting a length off the end in case it's the connection with the cap

When testing a stator if you get "bad" readings then stator is kaput........if you get "good" readings this doesn't mean the stator is "good", it could still breakdown under load or when warm. Try a different stator.

Sussed it I think! I knew it was something stupid. Went to fit a borrowed stator this evening. The flywheel is not turning when the kickstart is depressed ( ha ha)
I'd kind of half checked this (not properly obviously) because I checked whether turning the flywheel moves the piston - so that means the woodruff must be engaging with flywheel and its the kick start mechanism that's at fault

Im try to be philosophical and look on the positive side that at least its not cost me a new stator or cdi although I have wasted several weeks and exposed myself as an idiot on a popular scooter forum....

Are you sure the woodruff key is in place. Easy to find it stuck on a magnate. You say you turned the flywheel but the flywheel may not be turning as fast as the crank. Surely if you kick it Over can you not feel the compression even if the thing won't start. The only other thing I can think of is the clutch plates circlip dropping out but the kickstart will only be turning over the gearbox so no compression. Stick it in gear and try a bump start, if everything else is still connected it will turn over

Probably woodruff key but I did have the same thing happen when I sheared a crank pin! Could be clutch too... maybe.

Well I took the crank case off - thinking that I'd done something daft like not get the kickstart engaging with first gear. Put it all back together - its fine and crank is turning. So carry on putting rest back together, seems like my CDI is not working either so swap for a spare. Getting a spark. Try my old cdi to be sure, sounds like the may be a spark but I cant see one, apart from once so thinking at best the CDI is on its way out. Put the new CDI back on again, spark is back so think 'great - it was me being dumb AND the CDI' put the pipe back on, oil in, plug in to barrel, go to kick it over but it feels like the clutch is on and there is little compression, the flywheel is only spinning every now and again - maybe one in five kicks. I'm thinking clutch but what exactly? It was a pain to set up and get - I've got the ears bent up and the thinnest plates and corks I could get as that was only way I could get it so that the plates would separate and the top plate was not above the basket.