6-2 , 200pds riding a 08 ktm 300, awesome bike. The new 08 and up ktm 300's come mellow from the factory, you can tune them to hit as hard or soft as you want. Ignition map and powervalve settings can easily be changed in minutes. Mine is set up pretty mellow but I have a switch for the map, when the trail opens up, hit the switch and you get a lot more snap. You can change the way the power valve hits and the bike will become a monster. The new 250f’s are nice and easy to ride and would probably be a good choice. They seem to be a little more reliable these days. The new 450's are nice too, a lot more versatile than the old ones IMO. I just don't think you can beat a 2-stroke for simplicity and price. I’m surprised no one has mentioned modding a 250 two stroke with a flywheel weight. You can by a yz-250 and if it hits too hard throw a fly wheel weight on for 80 bucks and thing will turn into a tractor, mellowing out the bike big time. I had a kx-250 that had a pretty hard hit; 11oz fly wheel weight turned into a much easier bike to ride. Just something to think about, either way you’ll have a BLAST riding in the dirt. Mike
And I thought I was the only one! I positively suck at dirt bike riding. Knee down in the turns, front brake only. I spend a LOT of time cleaning mud out of my goggles and hemlet. Not to mention that my two worst crashes in the last two years were on my XR100R while doing a "fun" scrambles race series. Screw that. I'm getting slicks for that XR and pimpin' the WERA pit bike series.
2006 Honda CRF 250X. I'm 6' 205 lbs. I installed Race Tech springs front & rear, changed the gearing. The bike kicks ass. BTW- riding in the dirt vrs racing - I thought it would be easy....I was totally wrong!
Dirt is fun, go for it, so don't sweat the details, at least until you start to race and are trying to beat someone. Any dirt bike is more fun than nothing. A 250F is way better than a lot. A 250 two stroke is too. At 250 lbs., you might think ahead to when your skills develop and a 250F may not have the loft and pop you want, or you could buy something confidence inspiring now, and face that problem if it arises later. For reference, I am 220, I ride an '05 250 two stroke, I raced it Sunday, it goes way, way faster than me anymore, it doesn't struggle to haul me around fast enough, guaranteed, and I don't suffer for it having 5 seasons on it now. As someone said above, it is harder to go fast on a two stroke than a four stroke, but if you are just practicing or racing for fun, that doesn't matter. Practicing on an MX track or even on trails certainly will teaches you riding skills you would take much longer to develop on asphalt. Where are you going to push the front on asphalt? where is the ordinary mortal going to brake slide on asphalt? These things are fun!
steahly flywheel weight, about 10 ounces should work. and a good helmet. http://www.steahlyoffroad.com/weightsdet.php?s_partnum=715_
Two stroke is good for a noobie, much cheaper to maintain. Not too sure the reliability of the RM250 is quite up to Yamaha/Honda, but that is in part a matter of what you pay for it. The motor jumps up on the power quickly and the handling is quick, comparatively speaking.
How's your throttle control? How's the traction there? (Frequent rain but not muddy?) If you've got good T.C. and/or loamy soil it might work out. If you are ham-fisted and/or the trails are dry or muddy, you're in for a challenge.