sounds like you might not have a relay installed between your start switch and the starter solenoid. Especially if it is a new or aftermarket solenoid the coil inside of it requires a good amount of current to push the gear into engagement with the clutch drum.My bike was a kick-only till I scrounged up the parts to get it right. you didnt mention if it stays engaged after it starts which would be the drive gear. Did you replace the spring under the solenoid? The relay I am talking about goes inline from the battery to the small terminal on the solenoid and it is controlled by the start switch wherever you have it(mine is on the frame behind my left leg cause I smoked the tiny one in the handlebar controls) Mine is a 74 also which I have done everything but split the cases on so lets compare notes. FYI the alternator conversion kit from J&P cycles didnt work out.