Posts: 1544
Joined: 12/14/2010
Location: ORANGEVALE, CA USA
Ok i've seen a handful of 2 stroke builds converting to af frames. Im looking to do this but im having trouble sourcing a rm250.
i have a 13 rmz250 im considering not rebuilding
has anyone used another brands engine in another frame? i can find a handful of honda and yamaha's from the early 00's all day long
"If you feel in control, you're not going fast enough" ~Mario Andretti
Posts: 1297
Joined: 10/29/2013
Location: Boulder, CO USA
A lot of the swingarm pivot hole/width on the engine cases are going to be different from manufacturer. Which will make you have to come up with decent fabricated spacers to work inbetween the swingarm and frame rails, decent amount of work and needs to be spot on. I'd try to stay same brand. On mine, the old kx5 cases fit perfectly in the 09 frame/swingarm, but the cases had to be drilled out a handfull of mm to accept the latemodel swingarm pivot bolt.
-'09 KX500AF
- '19 KX450F
Posts: 921
Joined: 10/1/2011
Location: Highland Village, TX USA
Posts: 921
Joined: 10/1/2011
Location: Highland Village, TX USA
Spacers for the engine/swing arm pivot are simple to make if you have access to a lathe too. 
