We use “Extron Composite” sprockets. Or Horstmans or whatever if we don’t have the “plastic” ones. They wear well and don’t seem to get hot. Also “RK Blue O-Ring” chain. Same deal, holds the lub. really well. Again with road racing, the chain lub has to last a 30 minute race. So we use “Xeramic Ceramic Synthetic Chain Spray”. After 30 minutes it’s still nice and wet.
I suppose whatever is the best stuff you can get. We clean the chains and sprockets each day of an event with WD40 and a rag, then re-lub. Messy, but it works for us.
I gotcha, I run non O-Ring in my sprint karts which are 420cc Predator Motors on 35 chain and run endurance events usually 2+ hours in 206 class also on 35 chain without issue. I didn’t know if it was a 219 specific need or not.
219 is just a higher quality chain in general. Also the X30 makes about 32 HP which doesn’t help. We also road race 206’s, where we use good quality 35 chain. It never gets hot or requires more then a tiny bit of lub…unlike the X30!!!