Very hard to start when cold, kicks back very hard. Any thoughts? Timing issue?

First thoughts are flywheel key, but if totally sheared off & flywheel moved, it likely wouldn't run at all. Secondly--or firstly even, points gap way past 15 thou advancing beyond 3.2 btdc. Other thing is the choke working from cold, as don't want the idle screwed up too far or choke won't such good. Of course there's a fine line between too much choke & needing more choke. But generally from a cold start--no throttle at all & kick with choke on until it fires up & still don't tough the throttle until it settles down. Then again, if it starts & goes all lumpy then give it some throttle & flick the choke. Each bike will be different, "even though they shouldn't be", but a lot of things happen in 50 years, crank seals, mag side in particular. Worn rings ie low compression. Blocked choke jet in the bowl cavity. Oring on the jet setter causing rich running. & timing, points gap & crank key. Sorry--getting a bit off the original question.

Ok thanks, i'll check into some of your suggestions. After it warms up it runs and rides fine, just getting tired of getting my ankle beat up when I try to kick start it.

-Dave

Yeah mine did something similar come to think. I park mine for long periods & end up varnished up with old fuel & we have very crappy fuel here. I thought i'd cleaned the choke jet ok but must've has a bit more waiting behind it to get sucked up against the jet. Its the tiny brass drilling down the bottom of the cavity in the side of the bowl & has a tube fitting down there. Someone said recently they'd had that tube block up which i'd never thought of & never had happen. So there's always something new comes along to fool us. Talking kick back--360's take no prisoners. 250's are bad enough.