Is anyone from Colorado springs that can tell me how big of a motor i can put in my Yamaha blaster

[Michael crank]

 

[Markblaster]

You can fit any engine you like with a little work and modifying. Hyabusa engine would be fun.

Blaster engine is best option or DT200R or YZ250f or YZ490 or WR250.

Look here.
http://www.blasterforum.com/forums/engine-mods-and-swaps.129/