Modern Vespa

So recently did a fulll service on my Xmax 125.

Oil, final drive oil, oil filter, belt, rollers, brake pads.

Whilst stripping down the variator to access the rollers I noticed that (mostly on the roller side) the faces of the variator where worn and had troughs built into it, so essentially altering the gearing.

I had noticed recently a slight drop in performance. Mostly mid range to fulll power. So this means after the new variator and belt it pulls like a train from launch and goes right up to full speed effortlessly.

But.......

If at 35/40mph I have to back off behind a car (mostly on a hill) it's slow to essentially drop a gear and pick up again.

The variator change (after 20k miles) has transformed it a lot.

I'm now thinking the plates on the receiving clutch end might easily be as worn and not letting the belt release and slide back out of the trough.

I haven't had the clutch assembly out yet, but does this sound likely.

I've attached a picture of the variator plates and the marks highlight the groves worn over time.

The driven pulleys on my Honda and BV"s are steel not aluminum. At 23,000 miles I replaced the seals, O-rings and, seal collar and bearings on the Honda. When I replaced the clutch on the Commuter BV, I replaced the O-rings and the seal collar. The BV driven pulley's guide pins can't be removed, so I couldn't replace the seals and bearings. Obviously I re-greased them on reassembly.
I don't know about your Xmax but I bet the driven pulleys are steel. When /if you remove the clutch, check for grease in the clutch bell. No grease = no rebuild.
BTW your clutch shoes should last 40-50k miles.

The clutch itself won't make any difference at this speed because its fully locked up. If it was slipping ( unlikely! ) the rpm would be higher.
The variator will open up and provide higher rpm when the tension of the belt overcomes the force from the rollers trying to close the pulley halves. New rollers are probably a bit heavier than the worn ones and also have a bigger effective diameter so it could seem less lively in the intermediate speed ranges. The big spring on the back pulley affects/controls the belt tension so might be a bit tired. The after market springs can be a bit stronger to provide better acceleration but extra belt tension could cause quicker belt wear. Its also important that the belt is the correct length so a pattern belt of the wrong dimensions might ride higher on the front pulley.
You may just be noticing the effects of all the new components compared to what you have got used to so it could be worth just letting everything bed in. Alternatively you could try some lighter Dr. Pulley weights which would undoubtedly perk up the mid-range responsiveness.

Cheers guys.

Yeh just to confirm I didn't mean the actual clutch and it's grabbing etc.

Just meant if the variator faces where that worn then could I expect the faces on the non driven (clutch end) plates to look the same.

When I bought the new rollers I actually popped the old ones on the scales to ensure the 10g rollers I was going to fit where right.

The belt is an official Yamaha one too.

But yeh I agree and will continue to monitor as it all beds in.

The engine note has remained the same after the work.
As said from launch it really pulls we'll all the way to top speed.
It's only if I back off doing say 40mph going down to 25mph. The engine note drops and although it does accelerate once I'm WOT it's no where near as responsive as it was from launch or 0mph.

Best way I can explain it. It's still well within what I need to ride safely across my city but know that aspect could be better.

No. The variator(drive pulleys) are aluminum. The driven pulleys are steel. A stronger Contra Spring will help with that.

Thanks for the help guys.

I think It's sorted. Did a rapid strip down tonight at work doing the following.

1, bought fuel additive to clean the system, this is only a good thing but know it wasn't the solution.
2, bought new Yamaha genuine rollers and sliders as thought inferior aftermarket ones might be the issue.
3, Upon stripping down the variator to install the above I noticed the main body of the variator could/would not slide easily on the polished barrel.

Now on the Vespa LX this was lubricated by an oil soaked bush. On the Yamaha that isn't the case, it has an oil seal/rubber sleeve at each side. So upon inspection it was nothing but stiff. So variator would slide out under roller load but not return easily. I greased this lightly and with the other jobs above it's fantastic!!!

Power is now linear, no peaks and troughs just an even acceleration and engine note. It also when I back off drops to meet the engine revs. It pulls like a train, from launch. It backs off as it should and then immediately picks up again with lots of torque.

Essentially it's sorted. I just need to find out how much grease/lube I should smear/pack between the two seals....currently minimum.