Modern Vespa

I have been working on a few things on my scoot including a Malossi 190 upgrade. I have also replaced all of the hub bearings and in order to get the clutch shaft out I took off the variator nut and outer half of the variator. I ordered a new nut but there is a delay in getting one so I thought I would just use the same nut (new last time).

I put loctite 262 on the thread and attempted to torque it up. It would not reach the target torque value and the more I torqued the more worried I got. I decided to bail at that point the whole thing felt like cheese. I removed the nut and it looks a bit worse for wear. Not overtly stripped but the thread looks a but mashed. On close inspection of the shaft there was a lot of older loctite residue in the thread. I wire brushed the shaft thread and it looks ok.

So I have decided to wait until the new nut arrives and cannot check out the Malossi Magic until then.

Anybody else done this?

Haven't tried it personally but would be open to it if it involved a belt change at the side of the road without a new nut & plenty of loctite.

Given the amount of work involved in the 190 install I would advise to be being patient and avoid undoing the hard work.

Loose variator nuts can cause a lot of damage.

Yes a fair bit of work then I added the bearings. All done apart from the belt stuff. Nut due by Friday.

I'd get half dozen of them, being disposable and all.

Sacrilege on here I know but have reused mine probably 20-30 times. Always blue Loctite and factory torque value.

The one time I switched out to a new nut immediately lost the splines on outer pulley. Maybe just a fluke or Malossi 190 high compression and no decomp may have finally taken their toll. Decided not to mess with success and went back to original nut.

My take on replacement recommendation is Vespa is "covering their ass." Locking feature on the nut is a Bellville washer, not stretch to yield which is truly one-time use or crimp or Nyloc which are limited reuse. As long as washer still exhibits "cup" shape and spins freely, should be fine for reuse.

http://www.sealing.com/fileadmin/docs/Using_Bellville_springs_to_maintain_bolt_preload.pdf

i suspected as much and I think the mistake I made was not cleaning the old thread lock compound from the shaft. I noticed on the new nut I used last time there was a dry strip of thread lock compound on the thread. I also noticed that the outer variator half has next to no spline on it. Was like that when I pulled apart the first time. Should I replace the part or just torque it up? Seemed ok last time.

Yeah, don't want added running torque, and Loctite likes clean threads. Wire brush and pick tool, followed by acetone wipe is my MO. Nut not turning freely would be replacement criteria.

Today I took the original nut to work and had one of the engineers look at it. He run a tap 12 mm x 1.25 through and he said the thread was clean. I wire brushed the shaft thread and got the nut going on the thread smoothly with just light finger torque. I cleaned up the thread with meths applied loctite and it torqued up fine. I don't expect any problems but then again you never do, do you?

Unless the original nut is supposed to be an interference fit. *I don't have one of these scooters*