Motorcycle Repair: 1970 honda sl100, honda sl100, needle bearings

Question
how can i get spark without a battery? i dont have lights on the bike, all i want it to do is run. thanks   DA     
402-560-1784

Answer
Don, the bike was designed to be a battery operated ignition system. Any small 6v battery in the circuit will suffice, including gel batteries.

There is a way to make the ignition into a "energy transfer" type, but it requires carefully repositioning the rotor on the crankshaft, welding up the spark advancer to a fixed 45 degree (all the time) timing position, rewiring the stator and then probably buying a new AC ignition coil to make it all work. The time, effort and expense really doesn't pencil out over the cost of a small battery that is going to add about a pound to the weight of the bike. Just leave the rectifier in place, along with the rest of the wiring for the charging and ignition circuits.

Before you get all fired up on this project, make sure the camshaft isn't worn out in the cylinder head. These engines are known for loose cams, which affects ignition timing greatly when there is excessive sideplay in the camshaft fitment. The fix for that is either a new head and camshaft or machine work to fit needle bearings into the head and onto the camshaft.

Bill Silver