LCGB Forums

Hello.
I've heard the has been some issues with BGM stator plates. I'm experiencing issues with my engine not running properly. I'm using a BGM flywheel and BGM stator plate. I have checked the stator with a multimeter and the readings are ok, but I was wondering if they may break down under load ?
If anyone has had any issues, and has used a BGM flywheel and BGM stator, and found it has been either of these parts, then I'd be very grateful for any help or explanation of the problem they had.
Thanks,
Mac.

I've been using BGM stators in all my Lambrettas exclusively for well over a decade without a single issue. I originally used them with mid-weight SIL flywheels, but over the last several years I've swapped all of these for BGM flywheels. Never had a single issue in this time and my Lambrettas are ridden regularly. Only advice would be, as with any electronic stator, would be to check the pick up height. This is particularly important when mixing and matching components from different manufacturers.

Firstly, Make sure you have a good bonding earth wire connection betwen the engine casing and the chassis. All to often this simple but important point gets overlooked.
Resistance checks on LT coils usually prove to be worthless. Fortunatley, there is a better check.
The extremely fine wire on these LT windings usually breaks internally creating a ground disconnection. Mostly, the disconnection is intermittent making it difficult to diagnose. Often, the engine will run ok when cold and then stop when it gets warmed up and then run ok again when it has cooled down.
The best way to diagnose LT coil issues is to connect a multimeter between the green wire and ground. Set the meter scale to around 200VAC. (Analogue moving iron meters work best but digital meters can be used at a push. (You can buy these analogue meters dirt cheap on fleabay and the like)
At kickstart speed, the meter should indicate around 60VAC and max out at around 200VAC when the engine is running.
Ride around with the meter connected and secured in a visible position. (I usually gaffer the meter to the front of the seat) If the readings look stable even when your engine is running rough then it's likley that your issues lie elsewhere. (You will likley need some croc clips on your meter leads to ensure a confirmed solid connection here)
A problematic LT coil will give erratic readings on the meter needle as the LT coil begins to break down and give a near zero reading if it breaks down totally.
I always rework all CDI stators, new or otherwise, simply because this is a notorious issue with all brands of lammy CDI stators. Usually, I use a replacement LT coil from a Vethspa PX stator. Both ends of the coil wire are terminated to a separate ferrule on the plastic coil bobbin. As an addittional measure, secure the coil to the laminate pole by wetting the inside of the coil bobbin and also the stator pole and then affix the coil using Gorilla glue.
Now solder a short piece of wire to connect one end of the coil to the earth tag on the stator laminates and then solder the green wire to the other coil end ferrule. (PX coils usually involve cutting out a couple of the laminates on the stator pole to make them fit but they do work very well. (Use a small grinding disc on your Dremmel to do this)
If the coil proves to be the culprit but you haven't the means to replace it, then as an alternative, you could consider using a CDI unit that is powered by the lighting coils rather than the LT coil.
These CDI boxes incorporate an electronic inverter internally, which transforms the low voltage from the lighting coils to the 200+V required for the discharge capacitor.
If you ride to rallies etc, then carrying one of these CDI units can be a real "get you home", easy to sort lifesaver.