Modern Vespa

Hi guys.
Solo.Yorkshire-Biker here.
https://www.facebook.com/share/12EbHHA2EQZ/

I have a 2001 Piaggio X9 500 SL, i have a strange thing that has come and gone.

A clicking sound that only appears once pass 6,000rpm about 60-65mph, vanish if below That rpm or speed, when I get this sound I get a slight tug like feeling like a intermittent lost of power for few seconds but once pass this point the tug vanish but still high rapid ticking clicking sound, gets louder with rpm very slightly.

I have changed over the the year the following to eliminate:

New exhaust
Valves reset (twice) (cam chain not lose to the touch)
New clucht
New rollers
New belt

I'm at a loss as to what it is, has anyone experienced this before.

There is no loss in power no loss in top speed (102mph) power performance is spot on, starts up first push everytime.
Thermostat replaced and it warms up in few min.

Any ideas ?

On the stand or on the road or both?

Wheel bearings?

On road only.

Front wheel bearings replaced to eliminate that.

Ok, rear wheel bearings? They can bind and grind for a few seconds at a time while they chew on each other. On an '01 500cc scooter it's a very real possibility.

I replaced front and rear bearings on my '08 500 at about 18k and 20k miles, respectively, and about 13 years of age. (Head bearings too.) The fronts went first, but not by much.

Things got worse quickly, over maybe 100 miles, once they started acting up and the cause became clearer. I couldn't believe the wheels turned at all when I saw the rusty nuggets that came out of those races. Was happy to replace them with the most expensive Japanese bearings I could find. (Maybe they were $40.) They were still far less than the Piaggio OEM as I recall.

On the X9500SL the rare wheel does not have a wheel bearing, the wheel sits on a toothed spine that is then bolted on with 4 bolts, that then has the swingarm bolted it....that has a bearing on it that thr shaft and wheel rotate on, is it this you mean ?

If so I'll check the swingarm bearing the wheel sits on, I did feel it when last off when doing servicing and it felt smooth to turn ?

I'm definitely going to take it off take another look though as you have a good point, its one bearing that's never been changed.

Yes, that bearing in the swingarm is what I meant as the "rear wheel bearing." That could explain these symptoms if nothing else does. Just following Occam's Razor.

Any ridges or imperfections on the belt contact surfaces of the variator or driven pulley? ( on the surfaces used at higher speeds / rpms )

On a workshop job when trying to resolve a clicking noise we ended up recording the sound and then working out the frequency. Then matched it to what was rotating at that frequency.

Thanks for advice guys going to track this down

X9500 video...

YouTube link to the video

https://youtu.be/bfLhphP2oYQ?si=W034NQIWs17C9gQO

It is very difficult to distinguish anything subtle that is amiss from video, unfortunately.