Either i over tightened them last time or they are just pants…I remember struggling with them last time actually, but now with out any form of transport after changing belt and roller on the scooter. Unable to remove all of the 4mm hex bolts holding on the rear of the primary sheave with out them rounding off, so have had to drill them out and being on top of the weekend now new ones won’t be in at yamaha until Weds!

Gonna be a long time until then with a 21 mile cycle between home and work each way on top of a 12 hour shift every day until then  :/ 
Oh well needed to get back in shape!


If they’re just 4mm bolts, why can’t you just get them somewhere else?

Are they special?

If they're just 4mm bolts, why can't you just get them somewhere else?

Are they special?


I’m unable to measure the diameter, pitch, or length accurately as my brother has my vernier callipers and the yamaha parts catalogue only lists them as “bolt, Hexagon Head”

don’t want to risk ordering the wrong one and messing up the thread too :confused:

All though, on the plus side, my new toy made light work of the clutch and primary sheave nuts