Since no one posted anything and the misinformation is just flying left and right, I decided to call Mugen Racing and get the info straight from the horse’s mouth. It just so happened that Robbie Collins
answered the phone and this is what he had to say:
The plan was to release the .21 off-road (B01) and on-road (R01) engine at the same time. They did find something with the on-road engine that could
have led to a potential problem/warranty issue – which according to Robbie, was pretty minor. They just wanted to be sure that there wouldn’t be any problems, so they decided to have the issue addressed before the engine hit the street. Not one .21 on-road (R01) engine was ever sold.
The .12 (T01) is on schedule and will be released by the end of May or the beginning of June.
Thanks for clearing that up for us Robbie.