Originally Posted by Tbone
Go a local race and see what people are racing and pay attention to what guys in your class are doing well on. Talk to some of them..ask questions. I know I love talking motorcycles, even more so to someone looking to get someone involved in a sport I love.
this is the correct answer.
It's also far more important to spend your money on set up (ergonomics, suspension) to make the bike work for you
than it is on anything power related.
The woods KTM or Husvarna 4 stroke 250s are fine as is a well set up Yamaha. Keep in mind the KTM and Husvarna start as woods bikes, not MX bikes like all the Japanese bikes do. I know too many people with problems with Honda 250s to even consider one.
Not being worried about twisting the throttle too much is a great thing - don't buy a 450.