I am working on bringing a CT90 out of 20+ years of storage to running order. I had trouble with getting spark (see post "No spark in CT90) after I installed a brand new battery and it went dead. I purchased a new battery, put in new points, retimed (static) the stator and got good spark. I took it to the local ATV/small engine repair shop for tests. They wanted to see if they could get it to run w/o a battery...claiming it should. They installed an inline solid state ingnition thingie...to no avail. Perhaps there is a way to bypass the battery, but they couldn't do it. What I can tell you is that without a battery, my 1971 had zero spark. The minute I put in a charged battery...good spark. /s/ Clearwater