that's the whole thing with the speedways that have lights. i prefer the non-lighted speedways. because then you can put a tecumseh hs50 on it, and they go pretty well. you don't have to worry about lighting coils and the such, or tricking out a hs40. i guess that said though, you could transplant the lighting coil from the original hs40 to a hs50. but all the speedways i've ever bought had non original (or no) motor anyway, so that was never an option for me.
speedways sure don't come up for sale much, and when they do, they are always a mess. and owning a couple, i don't quite get the hype on them. i have two scarabs with hs50 motors and tav series 20 torque converters. i do like them. but are they better than a fox or a rupp? not that i can see. just a bit different. but they don't seem to ride or handle better. maybe it's because i don't have the 'special' models like a silver shadow or something...