Yamaha has used the Parallel twin many years ago with a 700cc or so version used in the Paris-Dakar rallye!!! The XT started in late 70's with smaller engines like 250's, then used some 500's and so on!!! THe last couple of years Yamaha hasn't been too heavily involved in Dakar. Dakar rules have also changed to allow only 450cc bikes (2011) to run in it. They have dwindled this down over the past couple of years to make it more competitive for more manufacturers. A few years ago, this is why we saw KTM dominating the Dakar, because Yamaha and others didn't have a large bike.