personal preference mostly. the way people describe it is "you sit IN a 1g and ON a 2g". performance-wise they're comparable. 1g gofast and repair parts are getting a bit more scarce. 1g carb life.... seems a bit complicated to me, so i stick to 2g bikes for myself
in a bike they should be. but as you can see the motor is out. i just stuck the hose on the other barb to make sure it doesnt spit oil all over the place when im cranking it with the battery