Reply To: Gt250r front sproccet nut
Sprocket Nut socket size is 27mm , and i agree that you need the rear brake pressed down hard with chain fitted to bike. Keep in neutral as not to damage gearbox
Torque for is 60-80nm for nut.
Use “PERMANENT/SEMI-PERMANENT” loctite on the thread , that can handle high heat , make sure the shaft thread is clean!
Also make sure shaft does not have damaged thread, because if a nut flies off, the sprocket will grind on the shaft thread , which could be an timely job to split engine and replace shaft again.
Folding washer to nut = I fold twice , and I make sure the washer lips are hugging the nut tight and flat… I do this for every customer bike.