Outer variator pully plate shredded again!

[Beaker99]

So, about a year ago I had the outer variator pully plate work lose and shred itself to death. When I dug into the CVT it was obviously my fault as the nut that holds it in place had come lose. Lesson learnt, I ordered a torque wrench and have been using that since to tighten to the required spec.

Fast forward until a few days ago and I’m on the motorway but struggling to keep my normal pace up. Instead of sitting at 120kph around the 6,000 rpm mark, I’m struggling to hold 100kph at 6,500 rpm. I get home and tear into the CVT and what do you know, that outer pully plate has lost all it’s teeth and can is spinning on the crank shaft. The thing is, the nut that holds in place is still firmly done up. I actually had a bit of trouble getting it off as there’s no way to hold the crank shaft in place if that outer pully’s teeth aren’t locked into the grooving. Anyway, what would have caused it to fail this time?
Everything else on the bike is fine. I haven’t noticed any other issues and I recently just clocked over 100,000kms on the old girl!

[Ruffus]

There are shims (different ID) to be put, most probably the outer one wasn't applied.
Or, wrong/too small outer pulley/fanblade mounted.

[Beaker99]

SOLVED - It was indeed due to a missing washer / shim. The inner one that goes up against the crankcase was missing. That allowed the variator to slide back a couple of millimeters, which was enough for it to loose some of it's bite onto the crankshaft. With the variator now free spinning on the shaft, all the driving force was transferred to the outer pully plate, and the soft alloy is obviously not designed to take that much force, so it then shreds the teeth that lock into the grooves of the crankshaft.

[Ruffus]

Good to hear its solved AND even better, nothing really bad happened.

Indeed the soft, outer fan blade is constructed as a security (inexpensive) item to save, in case of yours, the crankshaft of serious demage.

Thanks for your feedback and stay with us in this forum. Any contribution is welcome.

[people person]

So, about a year ago I had the outer variator pully plate work lose and shred itself to death. When I dug into the CVT it was obviously my fault as the nut that holds it in place had come lose. Lesson learnt, I ordered a torque wrench and have been using that since to tighten to the required spec.

Fast forward until a few days ago and I’m on the motorway but struggling to keep my normal pace up. Instead of sitting at 120kph around the 6,000 rpm mark, I’m struggling to hold 100kph at 6,500 rpm. I get home and tear into the CVT and what do you know, that outer pully plate has lost all it’s teeth and can is spinning on the crank shaft. The thing is, the nut that holds in place is still firmly done up. I actually had a bit of trouble getting it off as there’s no way to hold the crank shaft in place if that outer pully’s teeth aren’t locked into the grooving. Anyway, what would have caused it to fail this time?
Everything else on the bike is fine. I haven’t noticed any other issues and I recently just clocked over 100,000kms on the old girl!

[people person]

I see you have racked up 100,000ks on you KYMCO.I had a People 150s a few years ago but it was not fast enough for where I live, so 2 scooters later I found  an SYM gts 300 which I really like.I have thought about a Downtown 350 which looks a lot like the Sym in having a resonably low step through in front of the seat.{cant swing the 80 year old legs over the seat} Apart from your minor variator issue,do you find the Kymco to be reliable?

[Neil955i]

Hi People Person,

I've been riding Kymco 300's for a few years now and have found them to be reliable and inexpensive to run.  Like you arthritic hips make slinging my leg over a motorcycle a real challenge and I find the semi step through nature of the 300 a real boon.  Keeps up with most sportsbikes through the twisties too so, these days, 320ccs is plenty for me.