Originally Posted by tigmaster

well, heres a few basics but if you want more then check out this thread:
http://www.mototips.com/advanced-tec...-2s-vs-4s.html

basics are as follows:

2 Strokes: slightly high hp rating, only produce peak power in a small RPM range, harder to ride as in the right gear needs to always be selected, usually 5-10lbs lighter than the comparable 4 stroke model, ALWAYS CHEAPER. overall a 2 stroke is a great model if cash is tight not only for buying the bike but for routine maintenance.

4 Strokes: usually 1hp lower than a comparable 2 stroke, huge peak power throughout the entire RPM range with peak power starting at 2500RPM's usually with no dropoff on the top end, 4 strokes also now rev higher than 2 strokes and still produce their peak hp durring this, along with this immense power goes the fact that it doesnt matter what gear you are in just grab some throttle and it will haul on, slightly heavier about the dif in feeling between a full and empty gas tank weight, much pricier and require much more maintenance including oil changes and valve shimming.

personally i have a huge bias to 4 strokes but they are a bit pricier. they also offer many more upgrades that you couldnt get with a 2 stroke such as cams and lighter valves. personally i would say get a 4 stroke but its gonna cost you. wait until winter if u want a deal. right now they are going low at $3500 on ebay and i only paid $2000 for my 2004 rmz250. granted, i dropped another $2000 in high performance mods. and always, buy an mx series bike if u can. also, im not sure if you know this so ill just say it, a 125 2stroke = 250 4stroke and a 250 2stroke = 450 4stroke.