Downtown 125i makes same power as Yager?

[MotoRandy123]

I came across this today on a Euro site;


It says the Downtown 125i makes the same power as the Yager just at 1000 RPM's higher.
Hmmm Maybe it has 4 valve heads?

[Cortez]

Virtually all "performance" 125cc water cooled scooters are 11kW, which is a limit for
beginners' licences in most of European countrys.

Piaggio has been making the 125cc 'leader' engine for like 10 years or something, 11kW
from day one, and they've put it in everything from their own to Gilera, Aprilia and other
scoots.

Think Malaguti used them too?

[Zimmerman]

So how do you interpet this info, if it's accurate ?

Does it mean that even though the Yager has about 50cc's more  engine displacement that a poor engineering job was done getting the power out of it ? Which I would see as a bad thing.

Or from a positive viewpoint, is the Yager power plant 'under loaded' so it will last longer by running under capacity?

Should we ignore cc's and use HP instead to compare sccots ?

[Cortez]

So how do you interpet this info, if it's accurate ?

Does it mean that even though the Yager has about 50cc's more  engine displacement that a poor engineering job was done getting the power out of it ? Which I would see as a bad thing.

Or from a positive viewpoint, is the Yager power plant 'under loaded' so it will last longer by running under capacity?

Should we ignore cc's and use HP instead to compare sccots ?

It's a deliberate choice, no doubt about that.

The Yager was meant to be smooth and have good power and above average torque.

If maximum power from any displacement was the best way to do things, then you'd have touring, offroad and adventure motorcycles all using
the sport-bike engines. Would you like to tour/travel on a 500lbs bike with a 600cc engine with 130hp that peaks around 14.000 revs
and has no noticeable torque below 10.000 revs?
Probably not.

Honda just announced it's shipping it's CB1100 to USA and Europe, it's a 1100cc bike with "only" 75hp.
Their CBR1100XX had 160hp 10 years ago.
Their current CBR1000 has around 180hp.

Does that make the CB1100 a a poor engineering job?

Not to mention they absolutely kicked a$$ with sales of their new adventure styled NC700X introduced
this year, which is a 700cc bike with just 48hp!

There's examples like these everywhere, but 50 and 125cc bikes tend to shoot for the highest power
possible just because they'll be slow anyway, and difference between 6 and 7hp for example
is more then noticeable.

[MotoRandy123]

Well most everybody complains of not enough top speed. To push a scooter through the
air requires a certain HP. Here's a chart I found on a forum somewhere;

30mph = 1.64bhp. Much less than a restricted 50cc which normally have around 3.5bhp.
40mph = 3.52bhp.
45mph = 4.82bhp. The 45-50mph bhp figures are about spot on for a de-restricted scooter which can range from 4.5 to 6.5.
50mph = 6.47bhp.
60mph = 10.94bhp. Getting into the sport 70cc kit bhp figures and also 125cc 4 stroke bhp specs and 100cc's.
65mph = 13.76bhp. More like the Mid race 70cc kit bhp and the stock 125cc 2 stroke bhp.
70mph = 17.05bhp. A 125cc with just a 172cc kit fitted is around 17bhp and you will now start seeing the bhp figures increasing a lot for not much more mph.
75mph = 20.82bhp. A 172cc with pretty much all the bolt ons.

 Not sure how accurate it is. Many of the chinese bikes are lower HP for the same displacement so one would assume
something is not optimized with them. (some 250's make less power than the Yager!).

 Aprilia's make a lot of power. Their 170cc makes 17 HP to our 15 HP. That's a lot! I'm used to bikes where adding
5 HP via aftermarket upgrades is hard to do.

 The usual way to make power is by liquid cooling and 4 valves. The only thing we are lacking is the 4 valves. Of course
attention must be paid to the entire system, which from what I have seen, Kymco did when designing the Yager.

 I'm just amazed that the 125, 150, 170's seem to be about the same. It look's like they added weight so the power to
weight ratio is the same on all of them. Thusly they have the same performance. I'd expect the 170 to at least be a torque
monster, but it isn't.

 We do gain gas mileage. I was trying to get a most versatile scooter with great gas mileage. The carbureted bikes are
very bad on that point. Higher HP bikes might be too. They are always using the extra fuel.

 Of course you can't always believe everything you read. Those numbers could be wrong.

Here's a list of EPA certs I saved just for fun to compare power outputs of various models"

Alliance Powersports,HD 200 HD 200 EVO RV 200 RV 200 EVO,11,kW
Alliance Powersports,Citicom 300i,16.9,kW
Alliance Powersports,Mio 50,2.8,kW
Alliance Powersports,Symba 100,5.0,kW
Alliance Powersports,Classic 150,9.2,kW
American Suzuki Motor Corporation,DR200SE,14.9,kW
Amstar Motors LLC,ZN250T-10 ZN250T-18 ZN250T-18A ZN250T-39B ZN250T-39C ZN250T-9 ZN250T-B ZN300T-10 ZN300T-18 ZN300T-18A ZN300T-39B ZN300T-39C ZN300T-9 ZN300T-B,13.5,kW
Amstar Motors LLC,ZN250T-10 ZN250T-18 ZN250T-18A ZN250T-39B ZN250T-39C ZN250T-9 ZN250T-B ZN300T-10 ZN300T-18 ZN300T-18A ZN300T-39B ZN300T-39C ZN300T-9 ZN300T-B,13.5,kW
Chironex Inc.,Chironex Chase 150 Chironex Vinny 150,6.2,kW
Cobra Scooters,Madass 125,6.5,kW
Genuine Scooters LLC,Blur SS220i,11,kW
Genuine Scooters LLC,Buddy 50 Roughhouse 50,2.4,kW
Genuine Scooters LLC,Buddy 125,7.1,kW
Genuine Scooters LLC,Buddy 125,7.1,kW
Genuine Scooters LLC,Buddy 170i,8.2,kW
KYMCO USA,Yager GT 200i,15.4,kW
KYMCO USA,Downtown 200i People GT 200i,15.7,kW
KYMCO USA,Downtown 300i People GT 300i,20.9,kW
KYMCO USA,Xciting 500 Ri Xciting 500 Ri ABS,26.4,kW
KYMCO USA,Like 50 2T Like 50 LX 2T Super 8 - 50 2T,2.8,kW
KYMCO USA,MOVIE 150,9.9,kW
KYMCO USA,Agility 125 Super 8 150,7.3,kW
KYMCO USA,Like 200i Like 200i LX,8.5,kW
Panther Motors Inc.,P100 P125 P150,7,kW
Peace Industry Group (USA) Inc.,TPGS730-250 TPGS731-250 TPGS732-200 TPGS733-200 TPGS733-250 TPGS734-200 TPGS734-250,11,kW
Piaggio Group Americas Inc.,Vespa GTS 300 Vespa GTS Super 300 Vespa GTV 300,15.8,kW
Piaggio Group Americas Inc.,BV 350 ie,24.5,kW
Piaggio Group Americas Inc.,Vespa LX 150 ie Vespa LXV 150 ie Vespa S 150 ie,8.7,kW
Qlink L.P.,QLINK SM200-A QLINK SM200-B QLINK XF200 QLINK XP200,11.5,kW
Taotao USA Inc.,ATM150-B ATM150-C BWS 150 CY150-B EVO 150 LANCER 150 PALADIN 150 POWERMAX 150 ROMAN 150,5.5,kW
Yamaha Motor Corporation,TW200D1 TW200D1C,11.0,kW
Yamaha Motor Corporation,XV250D (V Star 250),16.4,kW
Yamaha Motor Corporation,XT250D XT250DC,14.2,kW
Yamaha Motor Corporation,WR25RD WR25RDC,22.0,kW
Yamaha Motor Corporation,YW50FDB (Zuma 50F) YW50FDR (Zuma 50F),3.0,kW
Yamaha Motor Corporation,XC50DW,3.1,kW
Yamaha Motor Corporation,YW125DB (Zuma 125) YW125DL (Zuma 125),6.8,kW
Yamaha Motor Corporation,YW125DB (Zuma 125) YW125DL (Zuma 125),6.8,kW "

Notice the Genuine Buddy 170i at 8.2 kw, that must be a mistake. I know the Yager
 is a mistake as it makes 11.4 kw or 15.4 HP.

 A scooter should be easier to tune as it has a narrow band that it needs to make power in. A motorcycle
has a much wider band. Maybe Kymco has limited the speed through HP limiting? I always felt the motor
runs great then just falls on it's face.

 I don't think the Yager will have problems from making too much power. It is built with high quality
components and  strong fasteners torqued to correct values. It continues to impress me!

[MotoRandy123]

 I would say if you have a motorcycle making 40 - 50 HP you can then
decide to make HP or torque (over a large range) thus making a fast
engine or a touring engine. At 15 HP you are not making enough of
either to "give up" some to make more of the other. You do have to
look at torque numbers to make sure they are tuned the same.
 
 I had a look at the EPA data and I don't see any of those 11 KW
125's being imported to the US. I thought the Movie 150 was going to
be 4 valve and have lots of power but don't see the numbers backing
that up.

[Cortez]

I would say if you have a motorcycle making 40 - 50 HP you can then
decide to make HP or torque (over a large range) thus making a fast
engine or a touring engine. At 15 HP you are not making enough of
either to "give up" some to make more of the other. You do have to
look at torque numbers to make sure they are tuned the same.

While I have no idea how much torque (and where) the Yager 200 makes, it feels
a lot more substantial down low then for example the Gilera Runner VX 125 that
once was in the family (one of those high revving 125cc/11kW piaggio engines).

That thing would hardly move at 7000 revs.. and it would positively fly at 8000.
The scream/noise from the engine always felt as even more performance was
there, but it wasn't really that fast.

On the other hand, the Yager is half the noise, twice the smoothness, and would
pull instantly as soon as the clutch engages, and respond to small throttle movements
that the Gilera didn't even notice.

Riding around town, you'd think the Yager is at least 50% faster in every situation,
but it actually never is, the Gilera would do 6-7mph more and was faster off the line too.

[Cortez]

Forgot to comment on another thing about the durability.

This was an issue 20 years ago, but isn't as much anymore with good brands.

While assuming that a 170cc/15hp engine would last longer then a 125cc/15hp engine
might sound like common sense, it only is if the engines use the exact same materials/
are built to same standards of quality etc.

Of course, they never are.

[Zimmerman]

Gents

Thanks for the replies. You guys have a better understanding of the interrelationships and trade offs of mechanical engine performance.

I'm very comfortable doing the same in the electronics world.  I'll re-read the thread and get a better feel on how to compare different bikes.

KZ

[MotoRandy123]

  Yes additional torque should make a big difference in take off. I never
rode one of those 125's and most data I've seen shows the 4 strokes to
to be balanced (15 HP and 15 Nm) which makes for a more versatile
ride.

 My one point of reference is a Virago 250. That started as a 125 and
then was stroked to 250. It made 20 HP and 20 Ft/lbs and I got 80 MPH
(indicated) and 80 MPG's out of it.

 I'm not complaining about the Yager's performance, just wondering if
there's anything more hiding in there?

 So far I haven't found much. It can breath a little better with a different
hose going into the airbox (and the rubber elbow removed) and some Dr. Pulley
sliders might make a slight improvement. An iridium plug might do a little then
it's only the suspension that could use some work. It's optimized pretty well from
the factory.  

PS I'm and electronic Technician by trade but I love tinkering and learning how to
improve stuff

[Zimmerman]

My wife and I ride our Yager and People 150 together all the time.

The Yager is faster and maintains speed better up hill.

But I find it interesting that the Yager isn't WAY WAY better than the P150.
The Yager has more cc's, EFI and water cooling - but it is over 60 pounds heavier.
Still the P150 isn't far behind the Yager with a lower price tag and more comfortable seat!

It's this daily comparison that got me wondering.

KZ

[MotoRandy123]

That is my perception too. It should feel way better and doesn't.

I assume there are limiters in there holding it back but the weight
 might be a big factor.

I know on a bike 10 pounds is = to 1 HP. I removed the rear grab
 rail/seat back/rack (as I got the Givi rack) so I must have taken
off 10 pounds so I gained 1 hp?

 I haven't found much else you could remove to get it lighter.

[Cortez]

That is my perception too. It should feel way better and doesn't.

I assume there are limiters in there holding it back but the weight
 might be a big factor.

I know on a bike 10 pounds is = to 1 HP. I removed the rear grab
 rail/seat back/rack (as I got the Givi rack) so I must have taken
off 10 pounds so I gained 1 hp?

 I haven't found much else you could remove to get it lighter.

No limiters there, just an engine that's meant to be smooth and
unnoticeable, there's other models for performance (but then you'd
be complaining about vibrations and noise, and probably fuel
consumption).
 

It's hard to remove weight from a scooter, but it's very easy to
tune the CVT to make the engine work a bit harder for more
performance.

If you need more then that, I'd just sell the bike and get a "bigger" one.

[MotoRandy123]

According to my calculations the 150 makes 73 ft lbs of torque max
                                                  170 makes 94 ft lbs of torque max

So that's why it pushes you and your passenger more easily up the hill.

 I tried making the rollers heavier to gain gas mileage but it interfered with
the clutch. It felt like the belt on the variator moved up the pulley then the
clutch engaged and it pulled the belt back down. It jerked a bit, so I decided
the stock weight is fine.

 I wouldn't want to make it rev higher as it already seems higher than I like.
Like I say, it seems Kymco did a good job squeezing out all the performance
they could while still making an enjoyable ride!

[Cortez]

According to my calculations the 150 makes 73 ft lbs of torque max
                                                  170 makes 94 ft lbs of torque max

So that's why it pushes you and your passenger more easily up the hill.

 I tried making the rollers heavier to gain gas mileage but it interfered with
the clutch. It felt like the belt on the variator moved up the pulley then the
clutch engaged and it pulled the belt back down. It jerked a bit, so I decided
the stock weight is fine.

 I wouldn't want to make it rev higher as it already seems higher than I like.
Like I say, it seems Kymco did a good job squeezing out all the performance
they could while still making an enjoyable ride!

You have NO IDEA how good it can be until you try Dr Pulley sliders. 
Couple hundred revs more at WOT, and couple hundred less at speeds above
50-55.