Friend Tony at Racewayservices put synthetic into my rig at 500km. I went back to mineral at 2500. It took until 18.600km after the second engine seize that the engine started to come free- Since 21.000km you could say the engine is running well.
At now 37.500km I still stick with mineral oil in the engine for to keep motor brake, as the experience for those 2000km with synthetic showed that the bike would push downhill like a 2 stroker.
As long you feel with each oil change that the bike performance improves stick to mineral oil in the engine. Probably 15.000km or more will pass by then.
For transmission and FD I use synthetic with the result that Sophie marks her terrain from there.
Patrol 2013 a Jim Petitti special.(RIP)
8 weeks 12.000km Oregon - Alaska - Oregon, now in CR 39.000km and counting.
With a DIY foam air filter the rig runs well even in tropical rain. The air box looks then like an aquarium.
Final drives: 1. at 5000km, 2. at 34.000km(+friction plates)
transmission: 1. 39.000km. 2. on its way.
The Avatar are 2 rice grains stating life's essence:
"The most important you cannot see!"
=> Attitude makes the difference!