Manuel, welcome, you can find info here and parts, we all try to take care of our rides and it's a great place to learn, and to share.
I bet you know about 'hot-soak.' That's usually related to a weak battery, or to an electrical system that needs work. The vehicle displays hard starting when warm.
Did you do the soldering of the wire loom splice where a copper or brass sleeve crimps the wires together? It costs nothing but time, and eliminates a power-robbing potential source of corrosion and poor electrical conductivity.
The early starter is a 2 pole design, later starters are 4 pole, and work better.
Check all your grounds, remove them, burnish them shiny-clean, and use a bit of dielectric grease upon re-assembly. Do the same with your starter hot lead, to eliminate any possible corrosion.
Check your wire connection from the stator 3 wires to the plug where they go to the regulator/rectifier. Since you already replaced them, you probably would have noticed if the plug was discolored, or burnt, which is a common occurrence, especially upon older bikes. The usual recommended fix is to solder the wires together, to eliminate the male/female plug. Be sure to use a good shrink wrap insulator sleeve on each splice. Secure the wires so they don't abrade or wear against a metal piece, eventually wearing-through and causing a dead short. Some people like pozi-locks for the splice.
Since you replaced the battery, you probably already examined the battery cables for being intact, but it doesn't hurt to re-examine them. Flex them along their length, and see if you find any suspect places where the wire may be corroded inside the insulated covering. I've had some experience on problematic components of the electrical system, where the crimp connection of the wire harness appears to be OK, but just next to that, where the wire insulation begins, the strands are corroded, leaving only a few intact. This causes a local hot spot, increased electrical resistance, and poor performance of the component. Again, flexing the wire along its path may reveal a 'soggy' or corroded area which needs to be spliced with another wire of the same gauge, and then well-insulated.
I hope that helps.