Re: warm up
i've built a bunch of bikes, most of them i never warm up, just blast off down the street.
i have built a few that needed a warm up, though. don't know why. one used to blow head gaskets all the time if i took off cold. resurfaced the head and jug everytime, made sure the head nuts were torqued, didn't matter.
the other one just sputtered along for the first half mile, and i'd have to adjust the choke 3-4 times when cold, then it would just take off.
usually, these bikes heat up quick, so if yours runs good with no warmup, go for it...