csnowden
New Member
Hi all, discovered much to my dismay over the weekend that the transmission drive axle/output shaft splines that carry the sprocket are worn on my 2004 FZ6 (S1), permitting the sprocket to slam about even with the clamping nut tightened to spec — I discovered this after riding home from work on Friday with severe vibrations throughout the bike as the sprocket was moving around on the shaft without me knowing. This is currently making the bike un-rideable for fear of risking further damage and also wrecking bearings inside the transmission with the uneven loading of the shaft as the sprocket wiggles around.
The S2 models (2007 onwards) changed the retaining mechanism to use a nut with a collar that gets peened into a notch on the end of the shaft, which is apparently far more reliable than the folded lock washer on the S1 from the reading I've done. My question is then, will the output shaft from an S2 fit into the transmission on an S1? Visually they look almost identical with just the sprocket end changing, it would be nice if I could just swap in the S2 shaft as a replacement as they seem to be cheaper and easier to get hold of.
The photo attached shows the wear on the shaft with the left-hand edge closest the threads showing the normal trapezoidal shape of the splines and to the right is nicely worn smooth on the leading edge. I've double checked that the sprocket still moves around even with the lock washer and nut torqued to spec, it was making one hell of a clunk as it moved around with just the back wheel being spun by hand. Judging by the rust this wear has been there for a while and both me & my friend missed it as we had the transmission apart last year to sort out a different issue, meaning to replace it I have to do the same work all over again... The noise doesn't seem to be usual Yamaha noises, chain rollers over the sprocket etc. but a definite clunk and vibration as the bike is in motion.
The S2 models (2007 onwards) changed the retaining mechanism to use a nut with a collar that gets peened into a notch on the end of the shaft, which is apparently far more reliable than the folded lock washer on the S1 from the reading I've done. My question is then, will the output shaft from an S2 fit into the transmission on an S1? Visually they look almost identical with just the sprocket end changing, it would be nice if I could just swap in the S2 shaft as a replacement as they seem to be cheaper and easier to get hold of.
The photo attached shows the wear on the shaft with the left-hand edge closest the threads showing the normal trapezoidal shape of the splines and to the right is nicely worn smooth on the leading edge. I've double checked that the sprocket still moves around even with the lock washer and nut torqued to spec, it was making one hell of a clunk as it moved around with just the back wheel being spun by hand. Judging by the rust this wear has been there for a while and both me & my friend missed it as we had the transmission apart last year to sort out a different issue, meaning to replace it I have to do the same work all over again... The noise doesn't seem to be usual Yamaha noises, chain rollers over the sprocket etc. but a definite clunk and vibration as the bike is in motion.
