Gears for higher top speed

[Mgalutia88]

Here is a picture from Maddiedog's thread. A large screen like he has will prevent much speed over 70mph. The takegawa variator is a good start to a solid performing scooter.

[wingz]

They look the same diameter to me, meaning you could achieve the same thing with stock variator and (possibly shaved) sliders.

[mikelx5]

the walls of the slides are a lot thinner making the weights go further out pushing the belt higher

[Mgalutia88]

heres an example of an aftermarket variator that has full length ramps

[Mgalutia88]

ill take a picture of a stock variator later to show how the ramps are different

[Mgalutia88]

If the ramps were clean it would be easier to see this. You can see how the two ramps in focus do not reach the top of the pulley. They are shorter than those on the orange pulley. This limits how high the belt can ride and your gear ratio.

[Mgalutia88]

Thus your top speed. This is why I'm saying upgrade your variator first. Your rpms are constant until the variator is completely extended then you start to raise rpms to redline. The longer the ramps the higher speed you are at before you reach lockup

[wingz]

Thanks for the photos and for making this an informative thread. I understand what you are saying. But to my mind, sliders achieve the same thing.
Ultimately the gearing will be limited by the diameter of the pulley hence my earlier statement.

Sendler explained it quite well here: http://www.hondapcx.org/viewtopic.php?f ... ign#p10155

There is nothing stopping the rear pulley from opening. It will open as far as the front pulley and weights pull it. Right to the point where the belt touches down on it's inside surface instead of running along on it's sides. There is untouched metal at the bottom of the rear pulley. Just as there is also at the top of the front pulley. We just need to get the weights to travel farther out the ramps. Takegawa machines the ramps in their variator to accomplish this. Dr. Pulley makes the control edge of the slider smaller to do the same thing. It is a brilliant design. They have still played it safe to make sure no application will raise the top edge of a new belt off of the top of the front pulley. I think I can find a few more mph top speed by removing material from the control edge of the sliders until I get full travel on either pulley. This will only help a PCX150 to go faster as a 125 will need engine mods to increase the power as well.

[wingz]

I've added blue lines to the photos below to illustrate the effect:

rollerweighttop.png (106.79 KiB) Viewed 1991 times

drpulleyslidephoto.png (109.23 KiB) Viewed 1991 times

[wingz]

This thread started out as question regarding ways to increase the gearing.
I put forward to gear options: Kitaco and Yuminashi.
Dasshreddar suggested larger tyres which is a nice idea but concerns have been expressed elsewhere: http://www.hondapcx.org/viewtopic.php?f ... 336#p28239
Mgalutia88 suggested an aftermarket variator. When I ordered my sliders I had thought variators would be prohibitively expensive. I now see that this is not the case.
One can increase the gearing by using sliders or by changing the variator however I doubt the gearing can be increased substantially because it is still limited by the diameter of the front and rear pulleys.

Below I have listed some options and their calculated increase in gearing.

1. Kitaco long ratio sprocket .................................... 3.9%
2. Yuminashi FORGED GEAR SPROCKET SET ................ 12.8%
3. 140/70-14 rear tyre ........................................... 3%
4. Variator or sliders .............................................. 6.6% ???

Just to clear it up, I understand very well that allowing the front pulley faces to move closer together will increase the gearing.
However, the extent to which this can be done is limited by the pulley diameter. It is no good moving the belt outwards so much that there is nothing for it to ride on.

To quote Sendler again from: http://www.hondapcx.org/viewtopic.php?f ... ign#p10134

Top speed is back up to 68 mph so there is a slight gain in the gearing there. I had been stuck at 66 for the last few weeks with .5mm wear on the belt already at 2,00 miles. I am hopeful that I can still see more top speed gains by tuning the control edge of the slider that is responsible for the high stop as I still have 2mm of unused pulley with the stock rollers. And I will take them up to 13gm to see what that does when I get my bike back. The epoxy will be very easy to drill back down if I want to lower the mass again.

I don't know the diameter of the pulleys but for to get a ballpark % increase in gearing lets assume it to be 120mm.
If we can make use of the 2mm of unused pulley on front and rear we would get and increase of 4/120 * 2 = 6.6%

There is not. Enough power with the 150 to take advantage they said. It was suggested to install a big bore kit and larger throttle body first. Their variator will give you up to 150kph or 93 mph. With a stock 150 we are expected to reach 135-140 kph. I will find out soon as mine is on its way across the ocean as I type this.

My stock top speed is 70mph. How can Yuminashi claim 93mph? That is a 33% increase in gearing which is 5 x the ballpark figure I calculated above.

[Mgalutia88]

93 is with a 164cc big bore kit and a 31mm throttle body. My point is that they are using a stock size belt with an aftermarket variator to achieve this affect WITHOUT their gearing kit. Check the thread for top speed with mods here where you have also posted.
http://www.hondapcx.org/viewtopic.php?f=9&t=1982
Sliders are great and are beneficial for 1-2 mph. However try sliders in the takegawa variator for a real benefit.

[dasshreddar]

Stock max speed for me was 67mph, bigger tire added 4mph and sliders only added 2mph... 73mph total gps verified
A performance variator should give even more top speed.

[mikelx5]

Im in the same boat as shredder besides stock tire. The slders dont push as far as u would expect i thought the same thing before i tried but gained about 2mph. The ramps dont allow enough movement. The bel will grip till it flys off never seen this besides it breaking. I built a 80 elite and found that as long as the belt is between the drive faces and it has friction it will grip.

[wingz]

However try sliders in the takegawa variator for a real benefit.

That will surely make full use of the pulley diameter. I'm not expecting more than 7% increase but I'll figure out the actual increase when I open the CVT to fit my sliders.
Someone on this forum (maybe even you?) had problems with sliders in a particular variator. Sticking or something.
This is the only reservation I have at this point.

It is nice to know that there are a few ways to tweak the gearing and various combinations can be chosen.

I still like the Yuminashi gear set because it gives the ratio increase I am looking for.
Alternatively I could use aftermarket variator AND larger rear tyre.

I'm not keen on modding the engine or increasing the rpm limit. I just need to run it at the optimal rpm (using sliders and/or aftermarket variators).

Also on my wish list is the Puig windshield that appears to reduce drag.

wind-scooter.png (36.47 KiB) Viewed 1970 times

[Pcxdemon]

While ago I had tested stock vario and Takegawa vario with same size weights in both 10g and Takegawa vario outperformed stock vario in acceleration and top speed. It was my Pcx vs my mates one. Although just by dropping his weights down to 10g made a marked improvement in performance over standard weight size weights.

PS Takegawa has slightly larger diameter face over stock vario but that doesnt mean much in terms of top speed. Im using Daytona vario currently and that one is same size as stock but has slightly higher top-end and better acceleration than larger faced Takegawa. It all comes down to the ramp profile. Also another very valid way to increase top speed without changing the vario , gears or tyre is buying outer performance pulley (the other half of the variator). Stock outer pulley is 15 degrees same as the vario but aftermarket ones are 14 degrees and some can be 13.5 or 13 degrees (real aggressive in their angle),im aware that NCY and AdvancePro are 14d..
and ive used both. Both times i gained 5-6km/h extra top end from them....

[wingz]

Hi PCXDemon. Thanks for joining the discussion. I have a few questions for you.
Sorry... looks like an interrogation but I'm trying to get a clear understanding of the whole picture.

1. Regarding the Yuminashi gear set...

You don't actually need to replace the speed sensor, just modify it. Pcxdemon knows about this.

Is it reasonably easy to modify the speed sensor?

2. As I understand it, the gearing ratio of any 2 pulley and belt system is determined by the ratio of the working diameters of the two pulleys.
eg: if the belt runs at a diameter of 10cm at the front and 2cm on the back, then the gearing ratio will be 10/2 = 5.
If the belt is running at maximum diameter on the front pulley and minimum diameter on the back pulley, the only way to increase the gearing is to increase the diameter of the front pulley.
This would then allow the belt to run at a larger diameter in the front.
What am I missing?
Is it that the variator has a larger diameter than the outer pulley? This would explain why changing the the outer face would increase the maximum possible gear ratio.

3. You mentioned the angle of the outer pulley.
Am I correct in saying that a shallower angle (eg 14° instead of 15°) will provide a smaller change in gearing for every change in engine speed?

[wingz]

Can someone please tell me the diameter of the stock variator?

[sendler2112]

Is it that the variator has a larger diameter than the outer pulley?

Most stock scooter transmissions have unused material at the outside of the front pulley and the inside of the rear. An after market variator can offer increased top speed by machining the ramps for the rollers to move out farther so that the entire pulley face is used. Even though the outer diameter is the same. Sliders can do the same thing because they can slide out farther than round rollers in a stock variator. If I wanted to, I could file down my sliders to get a couple more mph as I still have some unused pulley. If an after market variator has a larger diameter than stock, it will also need a longer belt to reach around the outside when the rear is bottomed out.

[Mgalutia88]

Yes Wingz I had a poor experience with sliders in an NCY variator. The Teflon coating inside it (the orange variator pictured earlier) causes friction issues with the sliders. NCY is the only variator with coated ramps that I'm aware of. As long as you stay away from NCY you won't have any problems. I have also used the NCY drive face with sliders in the stock variator and found no speed increase

On another topic, remember that the larger the windscreen the more air you must displace which devotes power to displacing air instead of top speed. Personal opinion... If you want to go over 70 mph stick with a givi 322.

That being said, I should have my yuminashi variator next week and will be testing it with my large biondi screen. We'll see how that goes.

[wingz]

Very good.
I suppose I could simply go with the 14° outer pulley and keep the stock variator. As Pcxdemon said, that combo should push the belt more towards the max diameter too.
What I like about this approach is that the outer pulley is cheap... $23.
Outer pulley + sliders has to be the cheapest way to get the gearing much better.
The "savings" could go towards a windshield.

I find the force on my chest quite extreme when riding over 100kph.
I can only really go on what others have said but the Puig looks quite streamline to me...

PUIG10971.jpg (278.84 KiB) Viewed 1956 times