I think in Nor Cal the 3 top classes are Stock Honda Cr125 shifter karts, Cr80 shifter karts, and Tag karts, not sure if there’s still a class for the ICC shifter karts or open class for 125 shifters.
May be worth giving them a call to see what classes are available, and the quantities of race entry/participants.
You’re right, the MotoX will help you a lot in terms of shifting gears, and multitasking, but with shifter karts you will experience a much faster pace, a lot more shifting up and down, a lot heavier G forces at the corners. Overall things will happen a lot faster, things will come at you a lot quicker, RPM’s will be a bit higher, as these motors like to be on the pipe.
Anyway the speeds are incredible crazy around the corners, and when chassis is properly tuned they are a blast, and lots of fun to drive.
I noticed you mentioned you have driven the TAG karts at Sonoma, just think of it as double the work to drive the shifter karts. And if you’re ok with that, then welcome to the challenge
I would totally start with a Yamaha KT100 clutch kart, then move up to a Tag Kart or a CR80cc shifter kart before jumping straight to the 125cc shifter karts, but who knows? You might be a very fast learner. I just wouldn’t race right away till at least I had 1/2 a season of practice under my belt.
Some of the guys that race at the nationals are pretty much perfect, and almost never miss a beat/shift, they really are accurate drivers, and would eat me alive at my age.
But yeah, contact the track at Sonoma and find out what club runs there and at any of the surrounding tracks, and ask them about the classes they run ( you don’t wanna buy the wrong kart/engine package) Only to find out there’s no class for it, or the numbers of entry are too small.
Those are my 2 cents, hopefully that helps you. Fast Freddy. ;)