I figured I would turn this issue into its own post in the proper subforum. I'm working on the Suzuki FA50 scooter. It has a magneto/flywheel driven ignition system with a CDI. Spark is good, coil and CDI are working fine and have been tested on a running model.
I put a timing light on tonight, as well as a dial gauge to confirm TDC. The flywheel is keyed. The CDI has a curve as pictured below. The ignition is a lost spark setup with two sparks per revolution of the crank.
According to the manual the timing mark on the flywheel should line up with the cast mark on the case at 4000r/min. The line on the left on the flywheel (marked TDC) is where the flywheel lands when the piston is at TDC - just for reference, I don't believe this is really relevant). The blue mark on the case is irrelevant but can be used for reference to the timing mark on the engine case on the second picture.
When rotating the crank with a drill (obviously not 4k rpm), the plug is firing at the blue mark on the case, which is about 90 degrees from the cast timing mark.
It just seems as though the plug fire is just happening WAY too late after TDC to ignite the mixture. Even at lower RPMs, the plug should be firing much closer to TDC. As of right now, it is firing halfway to BDC.
I rewound the primary coil on the stator, and I now believe that the new winding has somehow completely altered the point at which the charge is sent from the stator coil to the ignition system in relation to TDC.
My thinking is that I need to rotate the stator plate counter clockwise by making a backing plate for the stator itself, since the way its mounted only allows for small advancement/retardation of timing.
I put a timing light on tonight, as well as a dial gauge to confirm TDC. The flywheel is keyed. The CDI has a curve as pictured below. The ignition is a lost spark setup with two sparks per revolution of the crank.
According to the manual the timing mark on the flywheel should line up with the cast mark on the case at 4000r/min. The line on the left on the flywheel (marked TDC) is where the flywheel lands when the piston is at TDC - just for reference, I don't believe this is really relevant). The blue mark on the case is irrelevant but can be used for reference to the timing mark on the engine case on the second picture.
When rotating the crank with a drill (obviously not 4k rpm), the plug is firing at the blue mark on the case, which is about 90 degrees from the cast timing mark.
It just seems as though the plug fire is just happening WAY too late after TDC to ignite the mixture. Even at lower RPMs, the plug should be firing much closer to TDC. As of right now, it is firing halfway to BDC.
I rewound the primary coil on the stator, and I now believe that the new winding has somehow completely altered the point at which the charge is sent from the stator coil to the ignition system in relation to TDC.
My thinking is that I need to rotate the stator plate counter clockwise by making a backing plate for the stator itself, since the way its mounted only allows for small advancement/retardation of timing.