Modern Vespa

My brother an I installed a Pollinin max speed variator to my GTS 250 today. The performance increase is truly substantial (even with a PM Tuning pipe and chip in place. However, we had trouble getting the belt (Malossi) down more than about 1/2 a a centimetre from the edge of the rear pulley prior to reinstalling it. The belt seemed to go over the front pulley OK and the bike seems to be behaving as you would expect (though faster!!!) -- however I have read a few places about how important it is to get the belt well seated on the clutch end....is 1/2 centimetre enough to achieve this? Surely as the drive is used it will sort itself out? Should i pop the crankcase off to have a look or does it sound OK to you guys? If it needs attention how do we get it in further as I was pulling as hard as I could with my foot on the pulley to get to the point we did!!!!

Jam the rear wheel so it can't turn. Now you can twist the clutch open (grip hard, and twist anti-clockwise). It just opens up. Jam the belt in, and then use a cable-tie around the middle of the belt - this forces the front bit to open up to allow the outer variator pulley to be properly installed.

Thanks very much. Just so that I am clear - once the belts are on they won't just sort themselves out... And assuming I need to go in and reinstall the rear as you helpfully describe (using the brake will be much more effective than the mat!) could you explain a bit more what you mean about the cable tie for the front pulley?

There are plenty of pictures online for this if you know where to look. This procedure is exactly the same on a 250 and a 300, and the procedure for ANY variator is the same.

GTS 300 JCosta Installation





The problem with using a cable tie on the GTS is the idler pulley in the middle. You would normally put a cable tie in this position to stop the belt slipping out of the clutch pulley. If you don't have the belt deep enough in the clutch pulley, you will not be able to torque down the variator.

It's not a question of whether the belt will sort itself out when it starts moving, it's a question of whether the belt clears the front pulley halves so they can be torqued down properly. If the belt doesn't have enough clearance, then it will get pinched between the two pulley halves, and you won't really be torquing metal to metal.

Then, when the belt *does* move, the two halves of the front pulley will be loose, and you'll end up with serious engine damage.

Being an obsessive neurotic, I do this:

Before you put the transmission air filter back on after a belt change, I mark the position of the nut with a spot of paint where the nut and crank intersect. It is easily accessible through the screen.

Now, start the bike and rev the motor a few times to get the variator sliding in and out some.

Stop the bike and check to see that the mark is still intact. If so, I button up and ride it. I'll check it one more time after the first ride, just because I'm crazy, but after that you can be sure the nut was torqued properly.

P.

Indeed. You can see my left hand holding the belt so that the outer pulley half can be installed without pinching the belt. When it is torqued down, I then check to see that the belt is free to move in the front pulley.



@ Paul G... Good idea, though not necessary if you check the belt is definitely not pinched. I have been known to run the scoot for an instant without the transmission cover. Whilst this is not recommended, due to the clutch axle not being supported, I reckon it can do little harm as the rear is supported by the stand and therefore is not under much load. (Expecting flames here!)

Not suggesting running without the cover, just the air scoop cover.

It was me that does that. I realised your idea was a good'un! Belt and braces. Nothing beats belt 'n braces. Pity Piaggio didn't think of that when they designed the exhaust gasket!

I actually considered cutting a hole in the black plastic inner thing just so you can get a socket on the drive nut. Perhaps if someone at vespa see's this idea they could change the mold a bit. Its really dumb that u have to take the cover off just to rotate the engine over

Thanks all for the input. Now understanding the issue, we popped the cover off again tonight and checked that it was all seated properly (in fact the torque had been fine on the variator) and took Paul G's advice too with the paint dot -- so now its ready for some exhilarating riding if the test run is anything to go by -- with another check on the dot in a couple of hundred clicks.

Excellent. Thanks for the update.

I thought that the Pollini variator and Mallosi belt combo causes the belt to rub on the case. Are you getting any unusual rubbing sounds? If you have the cover off again it might pay to check the belt for witness marks of contact.

Steve

I hadn't commented before - but why use a Malossi belt? They tend not to last as long, and (IMHO) even if made in the same factory do not have the same standards applied. I think I am right in saying the Kevlar weave used in the OEM belts isn't cut in the same way, but properly finished at the edges. Whatever, the OEM ones are cheaper here as well, so win-win for Piaggio for once.

Malossi/Polini combination is the one that was recommended in the Scootering article on variators for the GT250. I couldn't see any hint of rubbing when I popped the cover off and cant hear any adverse noise so I think its OK...as for the comment on the OEM belts -- thanks for the heads-up - I'll definitely look to put one of those on at the first change -- have to say on the way home tonight with the new set-up it goes like stink -- but I'm guessing that the belt wear (and consumption) won't be so crash hot....never mind it really is a blast compared to the stock one.....

Very nice variator ~

http://uk.catalogo.polini.it/catalogo/en/risultato.php?op=mamoca&categoria=29&modello=958


Polini 6 rollers




New Polini 9 rollers