If no problems, I would wait for the chain/sprocket change service. Problems arise when someone overtightens the nut. Mine have the narrower nut with over 80000 kms and 2 sprocket replacements. No problems yet.
Quote from: rhinoeli on 01 April 2015, 06:17:42 pmIf no problems, I would wait for the chain/sprocket change service. Problems arise when someone overtightens the nut. Mine have the narrower nut with over 80000 kms and 2 sprocket replacements. No problems yet.Over tightening the nut has nothing whatsoever to do with it. The problem is quality control at the factory, the diameter of some output shafts were smaller than the minimum 17.5mm and the nuts were only gripping the edge of the threads, which caused fretting (A special wear process that occurs at the contact area between two materials under load and subject to minute relative motion by vibration or some other force.") and the vibration eventually caused the threads and tab washer to wear and the result being the nut falling off. Replacing the nut with the 12mm nut and tightening it to 80Nm or 90Nm maybe more reduces the fretting, but does not completely resolve it as the only cure is replacing the shaft. After some major issues with Yamaha with the problem, they eventually at 71000 miles relented to sell me all the parts I required to repair the problem at half price. While this was ongoing I tried a different approach which has worked and is still working after 12000 miles. The solution I devised is on the forum here http://foc-u.co.uk/index.php?action=downloads;sa=view;down=43 The new shaft I now have if I ever decide to install it is 17.82mm and the nut is tight going on it, compared to my original being 17.2, but nowhere the minimum 17.5mm.
Do you know if the threads in the upgraded nut are larger than the threads in the original nut (ie so they engage deeper with the threads on the shaft), or is the only difference the extra 3mm width of the nut?.Thanks.
To be fair I don't know whether or not I have a problem . The bike's only done 15k and I don't know whether the chain has been changed or anything. No idea whether it's gone back on a recall either.