Dyno graph for Pcx 125, 125esp and 150esp

[Pcxdemon]

Blue line is stock power curve and red is with Kitaco Gpr exhaust,im more interested to see '10 Pcx 125 making more power than revised newer ESP 125 Pcx...

[maddiedog]

That's odd, the eSP's power is far lower than the base. It's amazing the power gain the pipe provides on the eSP, but otherwise it looks about the same.

[Pcxdemon]

That's odd, the eSP's power is far lower than the base. It's amazing the power gain the pipe provides on the eSP, but otherwise it looks about the same.

Original 125 has way more power than esp model,more power on initial takeoff,more power thru the midrange and also more stable one and slightly more on top...Esp may have slightly better fuel economy than original model but at the expense of power...

[cessna151]

I wonder why it shows the 150 only producing 10 PS which is virtually the same as HP. Doesn't the 150 get more like 13HP? Or is that the difference between rated HP and actual HP?

[Pcxdemon]

I wonder why it shows the 150 only producing 10 PS which is virtually the same as HP. Doesn't the 150 get more like 13HP? Or is that the difference between rated HP and actual HP?

Shown is wheel hp, the graph is from actual dyno. Blue line is stock and red is with upgraded exhaust.

[sendler2112]

Do you have a link to the original article? It is hard to see what it says.

[sendler2112]

here is a good article on tuning a cvt scooter with a dyno. The charts show power vs wheel speed, mixture, and power vs rpm. A dip in rpm in the middle of the run is seen here also which they were able to fix somehow by just reducing the weights and changing the spring. Didn't change the torque slot profile. Keep in mind this is a two stroke with a narrow power band. Looks like a really fun machine! Yamaha Aerox with go fast parts.
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http://www.pedparts.co.uk/blog/moped-tuning-with-a-dyno
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I am anxious to put a camera on my PCX150 to really capture what it is doing with rpm vs speed during a full throttle run as I do not believe I have ever noticed it dip to a lower rpm in the middle of a run. I am on call with a service truck this weekend so my scooter is at work. Maybe next weekend.

[sendler2112]

I noticed this myself when I tried a heavier spring.
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"You only really need a stiffer torque spring for very high power bikes, basically the spring just has to be strong enough to stop the belt from slipping, any heavier it will just grip the belt too tightly and lose power due to the additional drivetrain frictional losses." It also loses top speed because it is crushing the belt into a slightly narrower width.

[Pcxdemon]

here is a good article on tuning a cvt scooter with a dyno. The charts show power vs wheel speed, mixture, and power vs rpm. A dip in rpm in the middle of the run is seen here also which they were able to fix somehow by just reducing the weights and changing the spring. Didn't change the torque slot profile. Keep in mind this is a two stroke with a narrow power band. Looks like a really fun machine! Yamaha Aerox with go fast parts.
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http://www.pedparts.co.uk/blog/moped-tuning-with-a-dyno
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I am anxious to put a camera on my PCX150 to really capture what it is doing with rpm vs speed during a full throttle run as I do not believe I have ever noticed it dip to a lower rpm in the middle of a run. I am on call with a service truck this weekend so my scooter is at work. Maybe next weekend.

Stiffer (slightly) spring can help the power dip against torque driver and also lighter weights alleviate to some degree but id say more like shift it to diff speed range but it still doesn't eliminate it completely...For perfectionists aftermarket torque driver is needed..
As i mentioned earlier Kitaco makes perfect spring for upgrading. Its slightly shorter than a stock spring but supposed to be 10%up over stock one. Next to each other when compressed by hand there is hardly any diff but makes big diff over stock when riding on the road. I tried Daytona spring thats supposed to be 3%up (stiffer) over stock but its longer than a stock one and in hand when compressed it felt way heavier than a stock one. On the road it was throwing my weights out way too much,it just didnt work out and i felt it was too heavy even at the claimed 3%up,so the length must have played the diff in overall feel on the road and its torsion.
Easiest way to by pass all that spring tuning is to just get straight grove torque driver and retain stock spring,the midrange power dip will be gone...More powerful torquier machines suffer less obvious symptoms as graph shows two models 125cc and a 150cc Pcx,you can see the 150cc has less of a dip but bit more linear flat midrange,that coupled with slightly heavier spring and lighter weights will be even less obvious which explains you having trouble feeling it out on the road (flat roads),hills are the most roads you will be feeling it if 'you're tuned' in to it. It seems 125cc models will benefit more from these mods. In saying you would deff feel the diff between the two if tried and i doubt you'd go back to stock driver.

[Pcxdemon]

This is a good example of how torque driver behaves. Notice how it takes off at 8500rpm and then settles (brings down the rpm) to 7900-8000rpm before gathers enough speed and rpm again to the same spot...Well in this vid this is the behaviour with lighter weights and slightly stiffer spring so its still fairly good in the vid but when riding in the country side it will always catch you out on the inclines and rob you of that sweet power spot and bog or hold you back till you hit the flats again. Now if you have a stock 125 your takeoff rpm will be 6900rpm and then they'll drop to 6200 or so and the midrange power drop will be much much more noticeable. With straight grove driver on takeoff when the weights are set for your own taste and lets say in my case,my rpm will shoot to 8000rpm, will stay there the whole time till the vario catches on and it will continue to rise from the rpm spot.No power dipping and always consistent rpm (consistent rpm is the word here)..In the vid i purposefully set the rpm for 8500rpm takeoff with dip loss in mind to keep 8k rpm when needed for full power pull but its annoying way to tune as one always has to compensate with weights to reduce the loss effect.
http://www.youtube.com/watch?v=Ig_tqwh85oM

This is what it sounds like with ample of power and torque on fully moded Pcx but still using stock driver,notice sound change at some 80kmh where just kind of relaxes it self while still holding full throttle? Its much less noticeable but to an eager tuner should pick that up..
http://www.youtube.com/watch?v=730HrZHCXJo

[sendler2112]

Now I see what you are talking about re the drop in rpm's from the progressive torque slot. I will video my 150 with 12gm sliders to compare.

[sendler2112]

Bump. Dyno testing a scooter requires taking the drive train apart first to lock the variator. See the above article on tuning a scooter.

[sendler2112]

This PCX dyno from Leo Vince makes it look like the aftermarket pipe is doing something less good to the top end. But what is really being shown is that with the Leo pipe, the speed at which the weights are already locked all the way out as indicated by the downward slope at the end (55mph in both cases lets say) is being achieved 5 seconds quicker.
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[sendler2112]

Another less than helpful dyno chart from Yoshi showing power versus wheel speed instead of power versus engine rpm.
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http://shop.yoshimura-jp.com/files/expa ... 0-53-0.pdf
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The only part of that chart that tells us anything is at the end, after the weights lock out, it shows the loud pipe is higher. Also shown is the dreaded rpm loss in the middle of the pull from the progressive torque slot as evidenced by the dip. This is why PCXdeamon recommends changing the rear pulley to one with a straight profile for the torque drive slot. Most bikes come with a curved one which helps keep the bike in top gear when re accelerating on the highway for fuel economy at the expense of less acceleration from not letting the rpms wind back up higher when you gas it. The PCX150 might have a different slot profile than a 125 because I see very little of this rpm dip on my bike with the stock pulleys.

[wingz]

I would like full throttle to result in peak power (eg 8000rpm regardless of speed).
Suppose I manage to tweak the CVT to achieve the above goal at all speeds when accelerating on a flat...
Does this categorically mean I would under all conditions (going uphill or downhill) get peak power at wot?

[sendler2112]

I would like full throttle to result in peak power (eg 8000rpm regardless of speed).

My USA 2013 PCX150 pretty much does that after just changing to 12 gram DrPulley sliders. full throttle pulls see the rpms climb quickly right up to 7.900 rpm where it stays until the gearing is maxed out around 50-55 mph. At which point the rpm has to increase with speed up to the rev limiter at 9,600 rpm and 68 mph. I also have very little, if any, of the dreaded rpm sag in the middle of the run that is common with other scooters due to the use of a progressive or two angle torque slot. My torque slot is progressive to look at (slightly banana shaped) but doesn't seem to behave that way much. If I try to look for any sag I can notice a 200 rpm drop when I enter a big hill at 40 mph and then gun it after the speed has started to drop. I only get to 7,700 rpm. But it is not enough of an issue to make me want an after market rear pulley to get rid of it.

[wingz]

I'm still a little confused. It appears that the rpm at WOT depends on driving conditions.
Am I correct? It would be nice to get peak power at WOT regardless of acceleration, slope, and the conditions prior to opening the throttle.

I would like to get the sliders.
Also keen to play with the springs. For example use a longer more compliant spring (spring A) or a shorter stiffer spring (spring B).
Compared to the stock spring, spring A would apply more force at low gearing and less force at high gearing.
Spring B would apply less force at low gearing and more force at high gearing.
I'm trying to figure out which would be better and why.

[sendler2112]

It appears that the rpm at WOT depends on driving conditions.

The first thing to do is get the 12 gram sliders. And a tach. Changing the torque spring doesn't have any effect that I could see that changing the mass of the weights wouldn't do and has the unwanted side effect of increasing the smashing of the belt. If you still think the stock progressive torque slot is holding the rpm down under certain conditions after changing to lighter sliders, you will have to get a rear pulley set with a straight slot.

[Slickvic]

Hey Sendler, which tach did you buy?

[sendler2112]

Hey Sendler, which tach did you buy?

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http://www.amazon.com/Koso-North-Americ ... B0041QMSE0
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Not the cheapest tach but very easy to install since it is powered by a button battery and uses a wire that is just wrapped around the spark plug wire for an inductive pick up. I wish it also had a clock.