If I was you I'd find a good tig welder, He / she might be able to run beads around the shaft thread to build it up and then re-thread it
Could you not drill down the centre of the shaft (using progressively larger drills). Then tap a thread in it. Then (with a load of loctite) refit and nip up the new nut and retain it with a big washer with hex screw down the middle of the shaft, again with loctite?
In my head it seems like a good idea...but also in my head these sprocket nuts shouldn't be failing or require such high torques as they are under no load?!?!
Quote from: Bretty on 02 May 2017, 10:26:16 amIn my head it seems like a good idea...but also in my head these sprocket nuts shouldn't be failing or require such high torques as they are under no load?!?!Yeah that does make me wonder, perhaps if Yamaha used a reverse thread, then the nut wouldn't spin off?
...The reason for it is that some bikes were produced with very slightly undersized (diameter) output shafts...
Quote from: fazersharp on 02 May 2017, 11:56:18 am...The reason for it is that some bikes were produced with very slightly undersized (diameter) output shafts...I've heard this said before. If this is true, does anyone know what diameter it should measure so we could check?
So how would my threads become worn if the nut had aways been on the shaft? My only thought is that it was manufactured under size.
A couple of decent spots should be sufficient.Coincidentally, I changed my sprocket this afternoon… angle grinder to cut the old welds and clean up the end of the shaft, new sprocket, old nut back on which tightened up just enough to clamp the sprocket firmly and a couple of fresh welds and it should all stay put.Nice idea to build up the shaft and then cut a fresh thread, you could actually choose a pitch suitable for the job. I doubt it could be done in-situ though, that much welding would probably get the shaft hot enough to roast the oil seal.
Quote from: Bretty on 02 May 2017, 12:23:13 amCould you not drill down the centre of the shaft (using progressively larger drills). Then tap a thread in it. Then (with a load of loctite) refit and nip up the new nut and retain it with a big washer with hex screw down the middle of the shaft, again with loctite?Yes, someone on here (Unfazed?) did this a while back, though I can't find the post at the moment.It certainly looked neater, it'd be interesting know how well it's held up.
Quote from: Fazerider on 02 May 2017, 09:44:46 amQuote from: Bretty on 02 May 2017, 12:23:13 amCould you not drill down the centre of the shaft (using progressively larger drills). Then tap a thread in it. Then (with a load of loctite) refit and nip up the new nut and retain it with a big washer with hex screw down the middle of the shaft, again with loctite?Yes, someone on here (Unfazed?) did this a while back, though I can't find the post at the moment.It certainly looked neater, it'd be interesting know how well it's held up.Check the downloads, http://foc-u.co.uk/index.php?action=downloads;sa=view;down=43 I uploaded the file of how I did it. A bit of a belt and braces job, used a circlip and a bolt with a washer. 16000 mile on it since I did it. Change the sprocket at 12000 miles and replaced the circlip, it still running like a clock.