Modern Vespa

Dear friends,

I have recently overhauled my Vespa 250 GTS' transmission system, with a new variator, fixed pulley, belt and full clutch assembly. It is now on nearly 42000kms and I have done approximately 25000kms on it since 2022, so it was time!

After installing all the new components, I have realized two problems with the transmission. The clutch was screeching on the start, but I knew that the clutch bell was old and it was glazed and had a lot of deep tracks of scratches all along. I tried to remove them with a sandpaper, but they are deep and I have ordered a new bell.

My real problem is the rattling sound that comes after I start accelerating. It sounds like a high frequency (the time interval between the beats increase with the revs) sound, a bit like glass or stone marbles hitting another hard surface. Sometimes it feels like the sound is gone, but overall, it is always there.

At the same time, I would like to share some observations with you, to see if helps at all. First of all, the new rollers that came with the variator, are completely open on side, as opposed to the old ones, with one side plastic, the other side metal. Could this be a "characteristic" of these new rollers?

The picture of the belts, the on the right is the new stock Piaggio belt and the one on the right is the Mitsubishi one that nearly ran 20000kms and still going,. The new belt on the left is only approximately 250kms old and I felt that there was so much wear on the tips of the threads. Could this be caused by any faulty part of mistake from my side in installing? I feel I might have a bit over torqued the variator, so would it cause problems like this?

I added a picture of the variator with the weights, just to be sure, I installed them correctly, now that the spec is changed, I was very confused about the direction of the rollers.

In all of this, could you please give me some ideas and advice as to see if I am doing something wrong? At the moment this is an ongoing process for me, and I will write my experience as I try new things. In this, the first thing I will try is that of course to see how the new clutch bell changes things.

The second thing is that I want to go back to the old rollers and variator and see how they sound in rev ups. For this, do you think it is a good idea to open the transmission and remove the belt and clutch and fasten the variator system to the 55 - 60 lb/ft torque and try the variator (engine running) with the old and new pieces to see?

Thank you all for your help!

The direction of the rollers of the variator is correct. The weight of the rollers is the same as the old one?

Geia sou Xristos, the rollers are 11grs, with +/- 0.1gr variations, but never less than 11.

This I know, because I have three sets of rollers, 1 set very old, 1 set one year old and one year brand new. I measured them all with my coffee scale, to see if the wear / mileage actually makes a difference in weight, but I don't think so.


The fixed pulley though, the old one actually measured 10grs lighter than the brand new one. I was sent two brand new fixed pulleys as a replacement, and the weight variation between the two were in about 1 - 2 gr range. The Malossi pulley I used previously was a complete different story, it revved very quickly, as it was considerably lighter than the stock, but it took the bike forever to develop enough torque. The top speed was increased by around 10kms, but I think the stock is way better than Malossi.

If your not into chasing top speed and going over 105kmh I would recommend some 11 or 12g dr pulleys. I used 11g dr pulleys in my gts250 for 10 years, much better than rollers in my opinion.

The Dr. Pulleys work ok with the stock variatore made by Piaggio, right?

Yes, they are made for the stock variator.

Have you had any luck figuring this out?

The belt wears along the v-sides. So I don't think the ridge tips wearing would be anything related to variator torque.

Does your bike have an idler pulley? Is that in good shape? Rotating freely? It's the only part I can think of that might contact the belt tips

The internal Ridge tips do wear off from normal use.