I agree with TJ here, but I think the reason it doesn’t work in karting is its sold often as a “spec” engine package even tho many people have theirs blueprinted. There was a class in the 4 cy world call F200 5 brands, it stared out as stock engines, and they were not competative at all. They came up with a genaric set of rules all had to meet, CC limit, carb size,Compression,cam lift and duration that you built all engines to. Suddenly, any or all could be players
Snowmobile racing is exactly the same, both kids and adults have their top levels where all 4 brands race together. Rules keep them equal and all 4 manufacturers are players in the same race.
Take Komet and KT100. 100 cc piston port engine. Give them the same carb set port dementions, spec compression and give them a spec or open pipe. Why wouldn’t that work with a 125 engine also? It always did in sleds, MotoX quads and bikes etc, many brands all race together, always did.
Its just so sad to see whats happening to this sport