With the old starting procedure, I would put the petcock on prime, pull the choke full open, then turn on the key and had to grind on the starter a lot before the bike would catch and keep running.
This winter, I came across a new starting procedure that seems to work quite well if the C10 has set for a week or so. This is what I have been doing. 1st, I turn the petcock to prime. Then I reach up and turn on the key (which allows the solenoid valve I have to come on) and count to twenty to give the fuel time to fill the carbs. Next I pull the enriching choke on full; then I tap the starter until the bike starts. It usually takes 3 or 4 taps to get the bike going. The bike also has stick coils, but I have had these for about a year before I discovered this new procedure. The bike stays connected to a battery maintainer, is in an unheated shop and has been starting in temperatures in the upper 20's.
If anyone tries this technique, please give me some feed back. HTH
THANKS, JD