Modern Vespa

Someone I know is selling off their 2018 Liberty 150. My wife has had a change of heart on learning to ride and it would be nice to have a scooter around the house again for town trips. Anyhow, I took it for a test ride and was a little underwhelmed with the performance for a 150cc scoot. It currently has about 1200 miles on it with good fresh gas ( I removed the older stuff before the test). I have tried to do some research on lighter roller replacement, but have not really found anything definite other than just some general advice. Has anyone on here tried lighter weight? If so, what weight did you go with that worked for you? I'm not really interested in going whole hog and replacing the entire CVT system - just the weights and maybe the contra spring. Thx

https://www.scooterwest.com/malossi-19-x-17-variator-weights-m669456.html

"Malossi 19 x 17 Variator Rollers in various weights. Click add to cart to see weight selections. If you have a 2015 or newer 3-valve engine on your Vespa Primavera or Sprint 150, Vespa 946, or Fly 150 you will want these rollers in 12.5 grams for a significant power increase. As a stand alone upgrade, these make a shocking difference on these engines. The factory rollers weigh 14 grams and really limit the potential that's built into these motors."

Scooter Fit

Piaggio Liberty 150 ABS (2017-Current)

C - thanks for the info. While I respect the advice from Scooterwest, it would be nice to get some feedback from a member on here that has tried this and what, if any, real advantage there is to going this route.

Lighter roller weights will make your bike shift at a higher rpm. Higher rpm (up to 7750 rpm) equals more power to the rear wheel. Bikes are tuned for fuel efficiency, low noise and low emissions from factory so have a low shift point.

I should add if anyone on here has installed lighter weights specifically to a Liberty 150, I would like to know your take on it.

So you don't want to hear from Primavera or Sprint owners which has the exact same motor.

Wait for Tom, OldSchooot to chime in on this. He is a big guy and has had his for years. He does all his own maintenance. The smaller wheel of the sprint and primavera makes this apples to oranges.

Wheel size has nothing to do with power output of an engine at different rpm.

I know it has the same motor, and yes I would like to hear from any Primavera or Sprint owners that have done this. But as Abner mentioned, it may be a little different. But I'm not really sure.

If you are trying to get the most power from an engine you would run it at the rpm that has its peak horsepower. Peak hp for our engine is 7500-7800rpm.

When you race someone in your car are you going to shift into the next gear at 3000rpm or let it rev up to its peak hp ~6000rpm before shifting?

I'm just going to reply to the OP's original request for info on different roller weights in a LIBERTY150i.

OK, some years ago I tried the lighter than stock 12.5 gm Malossi weights promoted by ScooterWest.

I am a big guy - and they were frequently tested on a long uphill which followed a stop at a local light. I'm in 45mph traffic and those around me were always in an almighty big hurry to get back up to speed!

These 12.5's gave me better acceleration - scooter climbed to a higher speed in less distance, less time.

So yeah - you should notice a difference in acceleration up through most of the rpm range.

I don't have a tach on my LIBERTY150i-S - but the reason for the increased acceleration being always present, according to the seat of my pants, is that I'm turning more RPM's.

At 35 mph the 12.5's are holding my engine at a higher RPM - than with the rollers at stock weight.

So - the motorsport claims are correct - "hidden power just waiting to be released!" as in 3rd gear has better acceleration than does 4th gear.

Me? - I tired of riding around in 3rd gear - and switched back to the stock rollers.
My engine is more relaxed as I cruise my dark lanes in a light rain....
And so am I.

I'm not late for work, I'm going for coffee.

Want more juice? - opt for the Malossi's.

O.S.

PS: you're not going to unseat your pillion. It's still a 155cc!

Would you say that the lighter rollers reduced top speed?
or
Lighter rollers raised rpm over most speeds, but still allowed same top speed as stock rollers?
Does the light roller, roll on suffer from 30-60?

I ride around WFO off the line which is comparable to most cars
Conserving momentum is my friend

I can imagine it also affected the gas mileage, yes?

We have an air-cooled 155cc motor.
Some report that different roller weights have an effect on top speed, and on mpg's.
I found no more than 2 or 3 mph difference in the few top speed runs I tried.
Then again, I often see small differences in every wot I try with this little motor, no matter the weights.

The scooter gets good mileage. Always did.
The number ? - honestly no idea. I've been fueling with a gas can for years...with rare exceptions.

I feel that the 12.5 Malossis are the best bet for most speed-conscious riders. Your top speed and mileage will be something you can live with....while your zip off the line will improve.
What it's doing to engine life is a mystery.

Honestly - if you need significantly more than the 12.5's...no substitute for more cc's!

I'm riding through my 8th summer, happily, with a stock drivetrain.
O.S.

Thank you, that helps a lot. Although I have been around and working in motorcycles/scooters for over 50 years, I still am learning.

After a little more research, some of the theory makes a sense. What did not make sense is that the 12.5 roller are being promoted for Primavera/Sprint and the Liberty 150 engine when they both have different OEM variator weights to start with. The Primavera/Sprint is 14.5, whereas the Liberty is 15.4. I'm guessing that this is to account for different gearing because of wheel size? Installing the Mallossi 12.5 weights in the P/S is a 2 gram drop, the Liberty is a 2.9 gram drop. If this purchase happens, I might be more willing to try 13 - 13.5 weights first. The 12.5 weight seem a little drastic when it comes to the Liberty. On the Primavera/Sprint, it seems to make sense.

Maybe they're rounding both to 15g.?
Then there's Dr Pulley's to consider.
Some swear to more acceleration and higher top speed.
O.S.

Yeah, that would be another variable with the slider vs rollers. A few years back in a thread you started, Motovista suggested 13 to 13.5 gram weights. I would be more willing to try that before going to the 12.5 weights. He knows a lot more about this than I do.

Please report back after you try.....assuming you buy the Liberty?
Thanks,
O.S.

I sure will. She is going to be checking it out Sunday, we'll see then.

The reason for the popularity of the 12.5 is that it is the heaviest weight Malossi offers in the 19X17 size, and that's a size that isn't used by anyone except Piaggio, so there aren't a lot of other choices. I think we tracked down 13 and 13.5, and if they're on the site still, we've got them.

Wheel size directly has to do with gearing though, outside diameter of rear wheel along with internal gearing drive ratio determines RPM at a given speed.

Different weight rollers determine RPM at shift points.

If the final ratio of gearing with diameter of rear wheel included is same for the Vespa's and the Liberty then the roller weight discussion should have Vespa owner input.

And in other words if the Liberty and the Vespa have the same top speed stock then they both have very similar overall gearing. The roller weight change effect should be similar on all models that share an engine if it is true that they have the same top speed stock more or less.

I put the Malossi Variator with whatever weights that came in the kit on mine and it definitely woke it up. The standard kit from Scooterpartsco.

Better all the way around, acceleration off the line, roll on acceleration, top speed. I also added an Akrapovic exhaust and a Q-36 Space Modulator, I mean the emulator thingy, at the same time so there is that.

The next step is big bore kit but still on the fence about that. It runs great the way it is but have no data on how it is holding up and have yet to check the plug for color to see if it may be to lean with.

It is a very nice setup. Easily keeps up with small motorcycles in similar around town driving. Not something I would want to take on the freeway for any length of time but certainly short blasts are doable.

I am thinking a similar modified Vespa Sprint or Primavera would behave also very similar. Pipe and variator and Bob's you're uncle!