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PCX 150 Further mods

Posted: Thu Jan 30, 2014 12:35 pm
by Mgalutia88
Hello all,
As some of you know I have a 150 that I have been modifying. Currently I have a takegawa silent sport exhaust, a 1.5" intake with K&N r1100 in the air box, a Yuminashi variator with Daytona belt, givi 322 short screen, takegawa reinforced lowering front springs, m-factory break pads and shoes, and a aftermarket seat. With all that I'm currently at a gps verified 73mph as coincides with the speedo and an unverified 79mph top speed. I have not tested this since I added the 1/4" larger intake.

All that being said I have an oil catch can that has not been installed (it's badly needed.)
Recently I ordered a tachometer and a takegawa ficon2, kn planning torque driver and a chameleon factory contra spring bearing.

I'm going to hook up the tach first to see where I'm at and then I'll update this thread as I progress.

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 5:40 pm
by Mgalutia88
So... installing the tach I found that at WOT accelerating in the variator from 15mph to 45mph im at 6900rpm with 12g weights. Am I testing correctly? How do others measure the rpms for weight tuning?

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 6:08 pm
by you you
Mgalutia88 wrote:Hello all,
As some of you know I have a 150 that I have been modifying. Currently I have a takegawa silent sport exhaust, a 1.5" intake with K&N r1100 in the air box, a Yuminashi variator with Daytona belt, givi 322 short screen, takegawa reinforced lowering front springs, m-factory break pads and shoes, and a aftermarket seat. With all that I'm currently at a gps verified 73mph as coincides with the speedo and an unverified 79mph top speed. I have not tested this since I added the 1/4" larger intake.

All that being said I have an oil catch can that has not been installed (it's badly needed.)
Recently I ordered a tachometer and a takegawa ficon2, kn planning torque driver and a chameleon factory contra spring bearing.

I'm going to hook up the tach first to see where I'm at and then I'll update this thread as I progress.
Has any of the stuff you have stuck to your twist and go made any positive differences?

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 8:03 pm
by Mgalutia88
The stiffer fork springs took the floating feeling away at highway speed, however on a really rough road you will get beat up, I love them and wouldnt change them for the world but once in a while you do get pounded.

My Givi 322 short screen is awesome for freeway cruising. I need to angle the shield down slightly to reduce helmet buffeting, however, it takes the air pressure off of my chest and puts it at my shoulders.

The Yuminashi variator allows me to cruise easily at 70mph (gps verified) and hit 77mph on a half mile straight (from 70mph) when i want.

Lastly the Takegawa silent sport exhaust (their cheapest option that looks similar to the stock exhaust) gives a good boost in power at the 8000+ rpm range and gives an ever so slightly louder exhaust note thats enjoyable to listen to. It really sounds like the stock exhaust just with the volume turned up. You can actually hear the engine in your helmet but at a pleasant level. At highway speed its pretty much drowned out by wind noise.

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 10:19 pm
by waspmike
I am still confused.

i asked this question
waspmike wrote:
Pcxdemon wrote: as it revs just below 8k rpm around 7700rpm,so just enough to lose valuable 1-2sec to 62mph..
So what's the current theory? It would seems that keeping the engine at maximum torque is not as good as keeping it nearer maximum power.

I've always wondered.
Below you say 8000 is the magic number yet here you say 6900. PCXdeamon says 7700
Mgalutia88 wrote:Whether hp or tq 8000 rpm is the magic number for our scoots.
Maybe the Yuminashi variator is made for primarily for speed increase not necessarily for optimum acceleration?

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 11:02 pm
by Mgalutia88
I'm saying I'm at 6900rpm. I'm out of tune with my weights and need lighter weights to raise my rpms. Pcxdemon was saying that 7700rpm is just far enough out of tune (Below 8000rpm) to loose 1-2sec in possible acceleration time. As in above 8000rpm would cut the time by 1-2 seconds. 8000 rpm is the magic number for best performance. As you make more power you need to lighten the rollers to retune your scooter. This is very similar to cars needing to adjust fuel maps or carburetor settings when changing performance parts.

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 11:02 pm
by Mgalutia88
Does this make sense?

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 11:18 pm
by waspmike
Mgalutia88 wrote:Does this make sense?
Sort of. But doesn't PCXDeamon have a 170 with after market cam? That would explain his 7700?

If from tests you have found that your scooter needs 8000 OK. But the more power you get the heavier the weights can be only 1/2 to 1 gram but... If you have after market cam that moves the power further up the rev range then yes you would need lighter weights.

Re: PCX 150 Further mods

Posted: Thu Jan 30, 2014 11:27 pm
by Mgalutia88
The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 12:11 am
by wingz
Mgalutia88 wrote:So... installing the tach I found that at WOT accelerating in the variator from 15mph to 45mph im at 6900rpm with 12g weights. Am I testing correctly? How do others measure the rpms for weight tuning?
Is that with the Yuminashi variator? Sliders or rollers? The size of the weights is also a significant factor. So is belt width and whether you put a spacer on the boss.
In fact I must put a spacer in mine because the belt doesn't go to the bottom of the pulley.

If you want 8000rpm keeping the rest of your setup the same, you could change to 9g provided you keep the same size/shape weights.
Also play with boss spacers if you like - that is what I'm going to do next.

To determine rpm, I record the sound and check frequency. I know this is very accurate. Tachs are not necessarily all that accurate.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 12:15 am
by wingz
Mgalutia88 wrote:The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.
that is a bad analogy.

We discussed this at length and more power pulls the weights inwards due to torque driver action.
You need to increase the weights when you have more power. That is why PXCDemon is trading his sliders.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 12:28 am
by Mgalutia88
I am using 12g rollers at the moment. I'm going to install a new torque driver first and then the takegawa FIcon2 and measure rpms again. Possibly I will switch to the belt yuminashi suggests (4mm longer according to PCXRacing) and their contra spring and inertia booster. Then I will start to tune from there. We will see what I actually do as the weather here is turning crappy fast so I may decide to tune as much as possible in the garage.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 2:55 am
by Pcxdemon
Mgalutia88 wrote:So... installing the tach I found that at WOT accelerating in the variator from 15mph to 45mph im at 6900rpm with 12g weights. Am I testing correctly? How do others measure the rpms for weight tuning?
I dare say for 8k rpm you will need 10g or under...possibly 9g!

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 4:22 am
by waspmike
Mgalutia88 wrote:The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.
Sorry I have to disagree here until I hear a better argument. Your is effect before the cause.

Honda is quite conservative with their stock weights so yes fitting lighter ones will give better performance up to a limit but that is not because the engine power has increased above its designed power, it is because you have allowed it to develop more.

The weights get thrown out by RPM not by power. If all else stays the same but only the power increases then the engine can carry a slightly higher gear than the lower powered one, so the weights can be slightly heaver to advance to a higher gear sooner. Example: If a 150 produces more power but at the same RPM as a 125 then the 150 should use heavier weights not lighter. All things being the same.

If all one does is change an exhaust there will be no change in the characteristic of the engine maybe a little more power but.... If on the other hand one changes the cam to push the power further up the rev range then lighter weights will keep the ratio lower longer to account for that.

If you change the ramp plate or a cheaper alternative machine different angles on the pulleys then the ratios will change at different times but still because of RPM not because of power.

It is a question of matching the RPM to the power curve. So if the right number is 7700 or 8000 then the weights go down until that is achieved. The power that the engine produces at that rpm is irrelevant only that it produces it maximum at your chosen RPM.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 4:43 am
by Pcxdemon
waspmike wrote:
Mgalutia88 wrote:The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.
Sorry I have to disagree here until I hear a better argument. Your is effect before the cause.

Honda is quite conservative with their stock weights so yes fitting lighter ones will give better performance up to a limit but that is not because the engine power has increased above its designed power, it is because you have allowed it to develop more.

The weights get thrown out by RPM not by power. If all else stays the same but only the power increases then the engine can carry a slightly higher gear than the lower powered one, so the weights can be slightly heaver to advance to a higher gear sooner. Example: If a 150 produces more power but at the same RPM as a 125 then the 150 should use heavier weights not lighter. All things being the same.

If all one does is change an exhaust there will be no change in the characteristic of the engine maybe a little more power but.... If on the other hand one changes the cam to push the power further up the rev range then lighter weights will keep the ratio lower longer to account for that.

If you change the ramp plate or a cheaper alternative machine different angles on the pulleys then the ratios will change at different times but still because of RPM not because of power.

It is a question of matching the RPM to the power curve. So if the right number is 7700 or 8000 then the weights go down until that is achieved. The power that the engine produces at that rpm is irrelevant only that it produces it maximum at your chosen RPM.
Getting all too technical here,lets keep it simple! Pcx either 125 or 150 or 170+ performs the best at 8000rpm without adverse fuel economy,regardless of what vario is in (yuminashi is not like a conventional vario as it has multiple angle face profiles so i cant speak for that one) ,its simple as that. Match your weights for 8k rpm and you'll be happy as larry, well, unless you are not performance inclined...

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 4:53 am
by waspmike
Pcxdemon wrote:
waspmike wrote:
Mgalutia88 wrote:The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.
Sorry I have to disagree here until I hear a better argument. Your is effect before the cause.

Honda is quite conservative with their stock weights so yes fitting lighter ones will give better performance up to a limit but that is not because the engine power has increased above its designed power, it is because you have allowed it to develop more.

The weights get thrown out by RPM not by power. If all else stays the same but only the power increases then the engine can carry a slightly higher gear than the lower powered one, so the weights can be slightly heaver to advance to a higher gear sooner. Example: If a 150 produces more power but at the same RPM as a 125 then the 150 should use heavier weights not lighter. All things being the same.

If all one does is change an exhaust there will be no change in the characteristic of the engine maybe a little more power but.... If on the other hand one changes the cam to push the power further up the rev range then lighter weights will keep the ratio lower longer to account for that.

If you change the ramp plate or a cheaper alternative machine different angles on the pulleys then the ratios will change at different times but still because of RPM not because of power.

It is a question of matching the RPM to the power curve. So if the right number is 7700 or 8000 then the weights go down until that is achieved. The power that the engine produces at that rpm is irrelevant only that it produces it maximum at your chosen RPM.
Getting all too technical here,lets keep it simple! Pcx either 125 or 150 or 170+ performs the best at 8000rpm without adverse fuel economy,regardless of what vario is in (yuminashi is not like a conventional vario as it has multiple angle face profiles so i cant speak for that one) ,its simple as that. Match your weights for 8k rpm and you'll be happy as larry, well, unless you are not performance inclined...
I am a dreamer and an optimist but mostly I'm pragmatic. Take the path of least resistance unless... :-)

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 10:11 am
by wingz
Pcxdemon wrote:Getting all too technical here,lets keep it simple! Pcx either 125 or 150 or 170+ performs the best at 8000rpm without adverse fuel economy,regardless of what vario is in (yuminashi is not like a conventional vario as it has multiple angle face profiles so i cant speak for that one) ,its simple as that. Match your weights for 8k rpm and you'll be happy as larry, well, unless you are not performance inclined...
Honda datasheet quotes peak power at 8000rpm for the PCX125 and 8500rpm for the PCX150.

Also, I still think it is worth experimenting with boss spacer to tweak rpm (in my case, at least)... when I get a chance.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 10:40 am
by Mgalutia88
Thx for making that point about 8500rpm

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 1:09 pm
by wingz
Regarding my statement about spacers...

I have calculated that I need a 0.5mm spacer to raise my rpm to 8500.
I know there won't be drawbacks because I measured the variator before and after fitting the sliders.
Fitting the sliders moved the variator pulley half towards the outer pulley by 1mm (when in lowest geared position) and I am planning to move it halfway back to where it was originally.
Now to find/make a suitable spacer. hmmmm.

Re: PCX 150 Further mods

Posted: Fri Jan 31, 2014 1:15 pm
by wingz
At this point, I wish to apologise and retract my earlier statement about minor changes in variator design being insignificant due the the rpmĀ² relationship.
I have now figured out that a 0.5mm spacer can make a substantial difference in variator controlled rpm.