The Honda PCX / Forza / ADV150 / SH Forums

The limiter wouldn't have to be any additional hardware, just built-in logic on the ECU. It would require no extra parts to implement.

That said, I'm not sure why they'd do it either. Wooley's theory makes sense in the UK, but in the US market, there are no such requirements. I'm guessing it might be to help keep the SH150i on a different market than the PCX.

I put a few thoughts up about the PCX limiter on Club PCX .

I've talked to a savvy Honda Spanner magician. The engine is limited 9500 rpm max, the speed is limited worldwide to A1 Limit(62.54mph - 100 kmh)

Whichever you hit first detemines the speed. If you go downhill on a decent road you hit the speed limiter way before full throttle. If you go uphill hard you struggle to get more than 50mph.

The PCX is catorgorically limited at the ECU via (as Maddie said) the rear wheel VS Sensor. It would take Honda OEM software and the correct plug in diagnostic to reprogram the speed - but it would probably come at a cost of increased fuel consumption and less reliabilty.

Sounds about right. Most mercs, bmws etc are limited to 155mph by the engine ECU. It receives a road speed signal from the traction control unit via the chassis can network. The limit can be removed by a remap of the engine ECU. Stands to reason the bikes are ecu limited as well. If this is the case then altering the gearing or fitting aftermarket variators won't make any difference to the top speed.

Thanks for the input rich, that's good to know.

I wonder how people get higher speeds than that without an aftermarket ECU then... Perhaps on a long downhill at full throttle, momentum takes them faster than the rev limiter allows or something odd like that.

maddiedog wrote:It would make sense that humidity has an effect on the engine, especially with you hitting a bit higher than my max. I can't get anywhere past 61 indicated no matter what, and it's humid here, whereas it is dry where you are. I still think the limiter is tied to speed -- if you put the scooter on the centerstand and gently rev it up to max speed, it won't go past 60 (or at least mine wouldn't). It would seem like, despite conditions, under load the wheel should be able to get going even faster.

I had forgot about that. I need to go see what mine will stop at on the center stand. I do also agree that there is some sort of speed limiter built into the ECU though. I'm guessing it just slowly tapers the fuel off. Like Wolley said, the speed limit is probably to keep it in the lower class for places like the UK. Why make many different models to ship to different regions? Just make them all the same. Plus the thought comes up, how much more would fuel economy suffer at speeds higher than about 60 mph? We have already seen that it makes a huge difference between people travel around 40 and people who do closer to 60.

I'm not sure if the loss in fuel economy at the limiter is from the fuel pump shutting on and off, or simply from so much gas pouring into the engine to keep it running at that speed. At the limiter, especially downhills when the engine isn't working hard, you can tell that the fuel cuts out suddenly and comes back relatively quickly (maybe 2 times a second). I wish the scooter had a tachometer, it might give much more insight into this.

I must disagree.
I do not believe there is any kind of limiters in the PCX.
It is the mechanical limit of the parts movement.
The variator plates touch each other with their centers, the belt cannot be stretched anymore physically, and therefore cannot spin the clutch any faster. You get to those 104km/h and sit there for the rest of the trip.
If you could stretch the belt more with the variator, you could open up the clutch more and get more speed.
You can test this by buying a brand new quality belt, from Malossi or smth. You will see that while it is brand new and a little wider than perfect, you get more top speed. After a few hundred kms, it breaks in and your top speed goes back to usual.

A solution to this is shaving off the centers of the plates a little, so they can get closer to each other when they finally touch. This stretches the belt more and gives us higher top speed. This is a permanent tweak.

Another way is having a belt made, which would be a bit wider. Same effect but in a different manner. Actually extremely effective because shaving the plates only tweaks the variator side, while the wider belt also affects the clutch performance. Just a tiny increase of width is a very effective measure. You might need lighter variator rollers to pull it.

geek77 wrote:I must disagree.
I do not believe there is any kind of limiters in the PCX.

Holy thread resurrection Batman!

Irrespective of what you may think, the original PCX as extensively discussed here and elsewhere at length all those years ago definitely does have a limiter.

gn2 wrote:

geek77 wrote:I must disagree.
I do not believe there is any kind of limiters in the PCX.

Holy thread resurrection Batman!

Irrespective of what you may think, the original PCX as extensively discussed here and elsewhere at length all those years ago definitely does have a limiter.

Stay calm, Robin! I am sure the question is old but I still haven't found a clear answer.

I could not find a logical explanation for a higher top speed with a brand new belt. This fact is totally incompatible with the limiters theory. The scooter does 113-115km/h and after 500km goes back to "normal".

I am sure everybody notices the same with every belt they buy, but nobody mentions it.

Maybe European version is different? I have seen mine close to 120km/h.

The pcx does not have a speed limiter. It has a rev limiter though (cuts fuel above 9500).
By raising the rev limit of the bike I've been able to raise top speed a bit. However downhill only as the given trasmission gear ratio and engine power characteristics does not push it hard enough on a stock setup to get faster.
It is useless though to mess with the Rev limiter as the power available is falling like an avalanche after the power peak about 8000.
Now if you're using longer gearing and an aftermarket vario to keep revs steady around the power peak about 8000 rpm at higher speeds too, then there is a higher chance to reach a higher top speed and protect the engine at the same time not bouncing on the Rev limiter.
The pcx is a neatly balanced little bike and built maily for in city commuting and relevant speeds. One has to mess with quite lot if things to get it better (some would say it cannot be done) however if you want to achieve something way out of the current envelope it's probably better to just exchange it to a more competent ride.
I understand however that certain situations might make that difficult (larger bikes are generally not avail or very expensive in most countries in South-East Asia, limitations in licence or others). For myself I just love to tinker with things and improve them.

EddieC wrote:dave - dont have mine yet, but should be here cal y time now. And the reason I got mine was for warmth, not so much rain, but it's an added bonus

You need it for baking bread under there? You live in SoCal for Pete's sake!
Cold?!
Come on a winter sunrise ride with me in Ohio.....we got cold covered! :-)
Fish

geek77 wrote:I could not find a logical explanation for a higher top speed with a brand new belt.

As the belt wears the gearing shortens, standard problem with all regular CVT scooters.

gn2 wrote:

geek77 wrote:I could not find a logical explanation for a higher top speed with a brand new belt.

As the belt wears the gearing shortens, standard problem with all regular CVT scooters.

Sure, I get that, I meant I could not find a logical explanation for this IF THERE WAS A SPEED LIMITER.

Some users suggested (strongly) that there is one and I disagree. Looks like they were not correct.

BTW, already getting in touch with the belt factory to have a belt with 1mm extra of thickness. This is gonna be fun.

Anybody from Portugal - start clickin: http://www.italcorindustria.pt/produtos/correias.aspx

geek77 wrote:I could not find a logical explanation for this IF THERE WAS A SPEED LIMITER.

Its a 125, they're all slow.
Logic demands that if you want to go faster than a 125 can manage you need a bigger engine.