Modern Vespa

What is the easiest way to get a measured 80mph out of a 2014 GTV 300? A $40 speed ring got my wife's 2020 GTS HPE up to that speed. I just want to be able to keep up when we need to pass big trucks.

I'm hardly any expert on this, but the HPE is touted as a more powerful engine. There may be no satisfactory answer to the question - "how do I make my 2014 GTV perform like a 2020 GTS HPE?"

Fit a Malossi V4 cylinder, piston and head, and than add an up-gear kit.

Get a motorcycle

the hpe was hitting it's limiter. the speed ring moved the limiter but obviously didn't change power.

the gtv will be limited more by power than limiter. ^^ this.

could also maybe try a forcemaster 2 but apparently hard to adjust properly with out a dyno.

I don't understand this at all, a 300 Vespa can't do more that that. My 07 GTS250 accelerate up to 85, the rev limiter stops it there. There was one time I glanced at the speedometer and it was halfway between 85 and ninety. I was not at WOT. I bought the scoot with only 4,000 miles on it. I doubt it had any performance upgrades. Can someone explain this to me?
Tony in Tn

the speedo in all unmodified vespa gts is wrong. check with gps. Note: the speed ring mostly corrects this

Years ago, Jess disclosed performances modification to his GTS for the 2012 Scooter Cannonball His goal was to go fast. He "upgeared" his bike, which I think means he changed out a gear in the transmission and some other mods to get his bike's performance up. Perhaps his original post from 10 years ago will be helpful to you. Have fun with it!!

Hope it helps.
Miguel

Install lead plating in strategically hidden locations on your wife's bike. Maybe lose a few pound yourself?

maybe just feed her more? and also stop drinking beer?

A cheap and easy way to "upgear" is to fit a 140 wide rear tire.

The added radius ups the gearing by a few percent.

I did this on my GTs and was able to get them over 80 GPS in good conditions. I hit 85 once on Rocket 🚀.

I have since gone back to 130 section rears and can't get any of them over 75.

Why did I do that?

Bill

Important to consider that "up gearing" or "down gearing" doesn't change the power output of the engine. It moves the balance of top end speed and acceleration in different directions. Worth pondering what is needed to pass a large truck on a highway (or any other use) - accelerate quickly to pass or achieve higher top end.

Not just GTS's or Vespas...pretty much all PTW's, motorcycle and scooter alike.

OP: I got a little more top end on my 2013 GTS with Dr Pulley slider weights instead of stock OEM rollers. (Just read up on how to avoid the rubbing issue.) I got a little more with a medium windscreen.

What weight sliders did you use?

I... don't remember.
I think it was a little heavier than stock but not overly so. I wanted it more highway-friendly but I didn't want to sacrifice too much low end because I was in the mountains.

I'll take off-the-line grunt over slightly-higher-topspeed every day of the week

I took the 300 out for the first ride of the season and was able to go about 74 miles an hour per GPS, 84 mph indicated. This is without any modifications other than a windshield.

This morning, I replaced the standard air box with a pod style filter. We'll see if that makes any performance difference. It's definitely louder.

As I understand it, messing with the fuel mixture is a 3 part process: air, fuel, flow. Increase the intake air without changing the fuel just makes you run lean. Increase the fuel to compensate without adjusting the exhaust flow doesn't do much but make you burn fuel faster. That's how it was explained to me, at least. I haven't messed with that since I switched from carb jets to fuel injection. Remapping the EFI is outside of my current skill set.

If you're going to run a more open air intake, keep an eye on your spark plug color.

Airboxes are designed to provide a still air plenum to reduce turbulence, as well as to silence intake noise. Some used bikes I've had were improved by replacing the airbox if I could find one not cut open to "improve" flow.

Next step is a forcemaster, which should address fuel ⛽ flow. But I'm doing one modification at a time.

sounds plausible ...

although I have a hunch: the restriction of the air filter would probably produce the smooth flow between the filter and the engine irrespective of what is mods are made between the filter and the open air. well, at least up to a certain point. maybe. sorta. ?

yes this hunch is ignoring the effect of length on standing waves etc which probably should be keep in tune with the rpms of the power band. ie don't fuck with the length of the hose etc between the filter and engine. switching to a pod and using the same hose running to the throttle body (like Lars did) would have minimal effect on this aspect unless the pod has such high flow that the smoothing effect I mention above doesn't happen.

hmm, just some waffly thoughts. not sure ...