Join Date: Apr 2012
Location: 9000 ft. ASL in Southwest Colorado, USA
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it says that nut is 10 mm? the nut I need to replace is 24mm and isnt listed? Its the axle nut (24mm) you have to loosen before making chain adjustments.
You've got things a little mixed up here... the 10mm nut you're talking about is used to secure the rear sprocket to the Driven Flange. Notice that this nut shows a quantity of 6... whereas there is only 1 axle nut.
Nuts and bolts are identified by the thread diameter and thread pitch, not by the size of the wrench used.
So the 16mm nut listed as Ref# 20 is the axle nut, and yes it uses a 24mm wrench.
The axle bolt has a 19mm hex head on one end... it is not a separate nut.
You are correct regarding the axle nut being on the left (or sprocket side) of the swing arm, and the axle bolt going through from the right side (brake side) of the swing arm... that's also how it is installed on my bike. For whatever reason the CBR250R Parts Diagrams are showing the axle bolt as installed from the opposite direction. Not sure if it even matters which direction the axle bolt is installed from. Probably six of one, half dozen of the other.
Former Factory Test Rider/Technician