its mostly just CZ stuff or variants Ali, not much Jap if any early YAm.
Freaky, It's really hard for you young whippersnappers to grasp the fact that there was a time in our sports history when Japanese bikes were considered uncompetitive crap. In pre 1975 Europe you'd have been flat out finding a Japanese bike at an average provincial race meeting. Sure, the Japs were winning GP's but it was on unobtainium works bikes. The more motocross savvy Euros were used to riding quality (for the day) bikes so they could tell a shitbox from a potential winner from 50 paces away, no need to actually ride them. The Japanese manufacturers knew that so they didn't export too many motocrossers to the European market in the early seventies. The RM Suzuki and monoshock Yamahas were the first bikes that they felt confident enough to offer to the Euros in any great numbers.
Add the fact that as all of the top makers at the time(CZ, Maico,Husqvarna, BSA and the Spaniards) were all produced in Europe, why would young Hans/Guztav/Miroslav or Nigel want to spend more money to buy an inferior Japanese product?
Disclaimer: Despite what might appear to be my slagging of the Japanese product of the day, my current bike roster actually concentrates on those very bikes. As uncompetitive as they were, I love 'em.