Flywheel differences

Newb here again, I know, asking obvious questions but hey I am that noob of noobs hehe
Anyway, what is the flywheel differences, I was sorted out a "Li" crank flywheel but its depth is totally too much by a couple inches by the looks of thinks, the spigot of the crank pin didn't even go through the centre hole and wondered, is there a difference in size for 125 engines to others, it is a ser 3 Li125.
The BGM stator fits in a treat but not the flywheel it seems
Its only this part that is holding the engine up now as the rest is ready to go, carb is good, new stainless "shotgun" exhaust, did the cylinder gaskets and had a look in there whilst it was open, good bore and piston, nice clean rings and clean recesses for the rings, compression is spot on and all the bits work like gears, clutch, brakes.
As for stators, I see Beedspeed do a Wassel conversion on a standard electronic stator of the owner, is this better or worse than a BGM and does it need a matching flywheel or does any electronic flywheel fit?
I will be prob heading for a 186 cylinder kit in the not too far off future and am thinking that everywhere seems to advise fitting a GP crank, do I need to change the mag housing for this upgrade or do I change the bearings to accomodate the difference in spigot?
OK noob session over...
Anyway, what is the flywheel differences, I was sorted out a "Li" crank flywheel but its depth is totally too much by a couple inches by the looks of thinks, the spigot of the crank pin didn't even go through the centre hole and wondered, is there a difference in size for 125 engines to others, it is a ser 3 Li125.
The BGM stator fits in a treat but not the flywheel it seems

As for stators, I see Beedspeed do a Wassel conversion on a standard electronic stator of the owner, is this better or worse than a BGM and does it need a matching flywheel or does any electronic flywheel fit?
I will be prob heading for a 186 cylinder kit in the not too far off future and am thinking that everywhere seems to advise fitting a GP crank, do I need to change the mag housing for this upgrade or do I change the bearings to accomodate the difference in spigot?
OK noob session over...