Dr. Pulley & Contra spring testing

Drivetrain upgrades, engine upgrades, or any other mods to gain speed or acceleration.

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sendler2112
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

Nobody wrote:Think that with a stock CVT system
Can you weigh your stock roller weights? I had read the stock weights were 15gm for the PCX125 but my 6 rollers from the PCX150 weigh 107gm. Almost 18gm each.
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Re: Dr. Pulley & Contra spring testing

Post by mikewasp »

What are you using for your speed timings. I need to but a gadget.
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

I use my cell phone. I have the dynomaster app for speed read out to verify the speedo and the phone comes with a stop watch but any wrist watch would do. My USA version speedo is verified dead on so I can just look at that for speed.
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Re: Dr. Pulley & Contra spring testing

Post by Nobody »

sendler2112 wrote:
Nobody wrote:Think that with a stock CVT system
Can you weigh your stock roller weights? I had read the stock weights were 15gm for the PCX125 but my 6 rollers from the PCX150 weigh 107gm. Almost 18gm each.
Will have to see if I can find some scales at work and borrow them. Don't have anything for grams at home.

There is a thread somewhere on weights - the Thai 125's have 18g rollers while the rest of the world have 15g as standard.
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Re: Dr. Pulley & Contra spring testing

Post by mikewasp »

Nobody wrote: Will have to see if I can find some scales at work and borrow them. Don't have anything for grams at home.

There is a thread somewhere on weights - the Thai 125's have 18g rollers while the rest of the world have 15g as standard.
Put the weights in a Jiffy/padded bag addressed to yourself take them to the post office and ask how much they weigh and how much to post. When they tell you change your mind and leave.
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Re: Dr. Pulley & Contra spring testing

Post by djcat »

Hi, do the sliders affect top speed?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

He didn't gain much but there is quite a bit of unused travel on the pulleys of my PCX150. I should be able to hand trim a set of sliders to get the belt all the way out.
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Re: Dr. Pulley & Contra spring testing

Post by Nobody »

djcat wrote:Hi, do the sliders affect top speed?
From what I have seen, not a lot. Maybe just a couple extra km/h over stock. They are a quality product and on a lot of bikes give a decent increase, just not on my PCX. But they also last a lot longer as they do not square off like normal rollers so still recommended.

Been running with the stock rollers for a while and not bad with the up-rated contra spring. Really recommend doing a spring job! Have to get some other rollers at some stage. Want a bit more rpm's on acceleration than what I'm getting currently as I have tasted acceleration at over 8000 rpm now. ;)

Sorry Sendler, no chance at the moment to weigh mine either. Busy as hell with work, travel & family.
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

Nobody wrote:
djcat wrote:Have to get some other rollers at some stage.
I think it would be pretty easy to make your sliders heavier if you had access to a good triple beam scale which could easily tune them all back into balance within a couple 1/100 of a gram after adding some epoxy putty to the center of each one. I only got one ride in with my my 12gm Dr. Pulley sliders before hitting the dog and it was dark so I can't say much yet. I think they may be still a little too light for the best trade off between performance and economy. I did ride it down to leave it at the shop the next day but didn't spend any extra time to really see what the changes are. The 30 mph cruise rpms are up to about 6,000? The sliders are much more responsive than the rollers. Less friction? The revs jump right to 7,800 when cracking the throttle and it is pulling at 8,000 by 40mph but the revs drop straight back down to 2k rpm when reaching a cruise.
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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.
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Re: Dr. Pulley & Contra spring testing

Post by gn2 »

sendler2112 wrote:I still have 2mm of unused pulley with the stock rollers.
Is there a corresponding band unused at the centre of the rear pulley?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

gn2 wrote:
sendler2112 wrote:I still have 2mm of unused pulley with the stock rollers.
Is there a corresponding band unused at the centre of the rear pulley?
Yes.
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Re: Dr. Pulley & Contra spring testing

Post by gn2 »

Is it possible to get the belt further down the rear pulley, will it open up enough?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

The only stop in the rear is to the inward travel, or low gear. The front stops the high gear by the machining of the weight ramps. Which is why the sliders are able to take the stock variator to a higher top speed.
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Re: Dr. Pulley & Contra spring testing

Post by gn2 »

In order to get the front pulley to close further pushing the belt further from the centre, surely you need to get the rear pulley to open further?
Or does the belt stretch?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

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.
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Re: Dr. Pulley & Contra spring testing

Post by gn2 »

Have you worked out what the gear ratio/development will be altered by if you use the currently unused sections of pulley?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

gn2 wrote:Have you worked out what the gear ratio/development will be altered by if you use the currently unused sections of pulley?
Works out to higher top speed.
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Re: Dr. Pulley & Contra spring testing

Post by gn2 »

Only if the engine can push the longer gear ;)
I was wondering how much longer it is in percentage terms.
I take it you haven't calculated it?
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

I am redlining at 67 mph now on my 150 so I have plenty of power to go longer on the gearing.
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Re: Dr. Pulley & Contra spring testing

Post by sendler2112 »

This brings up a common misconception about going longer on final gearing in a motorcycle. This has been discussed at length at the CBR250R forum. "You can't go longer, the bike can't pull the gearing it has." "It will bog down and kill top speed." The fallacy is that the bike has to be geared to hit the redline at top speed. Like my PCX is now. This may be a good compromise of acceleration vs top speed but the best top speed will occur at the power peak. Not the redline. Most bikes have a power band that is tailing off well before redline. My top speed went up when I put 15% longer gears on my CBR from 92 mph to 96 at 8,500 rpm. It has a 10,500 redline. The PCX will behave the same way. I haven't ever seen a dyno but I believe it is making more power below 9,000 than it is at redline so going longer on the gearing by pushing the belt higher on the front pulley could also raise the top speed of a PCX125 by pushing the top speed rpms down toward the power peak. At the slight expense of 50-60mph acceleration. Contrary to changing the sprockets on a motorcycle, all other acceleration for the scooter below the variator lock up speed would stay the same as we are not changing any of that. Here is the CBR dyno and optimum shift points showing that even in regards to best acceleration, The only gear spacing that is so wide that it benefits your time to shift at redline is the 1-2. The lower line in each pair is the stock bike and the upper line shows the power that can be gained by changing to a loud slip on muffler.
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