Too light?

[mrmike]

     I want to get better acceleration from my X-Town 300i. Has anyone had the variator apart on their X-Town? I would like to know for sure what weight the stock rollers are. I bought a new set of Dr. Pulley sliders for mine. I thought they were 16g, but I just weighed them, and they are 15g. I don't want to go too light and kill all my top end. I don't want to pull the variator apart until I know for sure. I believe the stock rollers are part # MF-2-2-16, but I'm not sure that means 16g or not. If so, then 1g lighter would be just what I want.

Just saw the chart posted in the forum. It says my stock rollers are 17.5g. If so, how much top end will the 15g sliders kill?

[Stig / Major Tom]

I was informed (reprimanded) by a Vespa mechanic for my belief that a lighter roller with give better acceleration ...but at the expense of a few MPH's at the top end.
"Better acceleration but lower top speed."...I thought.

He said I was dead wrong. That a lighter weight roller will improve both the acceleration and the top speed.

Which kinda makes me wonder why the manufacturers don't know that?


anyway - you won't know if those weights will suit your riding style, unless you try them.
Stig

[big blue]

When I installed Dr. Pulley sliders on my Like I went 1gm lighter than the stock rollers and got better acceleration and top speed. The sliders ride higher in the variator ramps due to their shape so the belt rides higher as well.

[mrmike]

   I know lighter will give me better performance. I did it on my 2012 GTI 300 and was very happy with the results. I'm just concerned that if the stock rollers are in fact 17.5g, and I go to a 15g slider it may be too much on the X-Town. I already bought them, so I'll just try them and see. I just hate doing the same job twice if they don't work out!

[Stig / Major Tom]

When I installed Dr. Pulley sliders on my Like I went 1gm lighter than the stock rollers and got better acceleration and top speed. The sliders ride higher in the variator ramps due to their shape so the belt rides higher as well.

Good point Blue.
Dr P 'sliders' are known for that ....rollers , I don't know if they truly do the same on both ends as the sliders.

Stig.

[Iahawk]

I went 1 gram lighter with sliders on my S200 with better acceleration but no real difference in top speed. I went 3 grams lighter with sliders on my Helix 24 gr down to 21 gr (23 and 22 gr were sold out, everywhere). Better initial acceleration but no change to top speed.

[mrmike]

       Thank you all for your input. Once I get a few more miles, I will do an acceleration and top speed run. Then I will tear the variator down and get an accurate weight on the stock rollers. Then I'll install the Dr Pulley 15g sliders and do an acceleration and top end run for comparison. I'll let everyone know the results.

[Stig / Major Tom]

My issue with lighter roller weights, and too light sliders, is the increased engine speeds at same over the road speeds.
I don't like listening to my engine spinning higher for no reason.
Stig

[Tromper]

You do technically lose potential top end speed that you would probably never reach with the OEM rollers.
The trick is that you really will reach the actual top end with the lighter ones.

DPs vs. rollers.  I have two almost identical bikes, & ran 1g light sliders and rollers in 'em side by side.
1g lighter was definitely the right thing for this bike (SYM HD200), but there was marked difference throughout the range with the rollers vs. sliders.
As you'd expect the top end with the rollers was definitely getting pretty revved up, but the sliders really aren't too bad.
Off the line.  The punch of the rollers was markedly different from and a bit quicker than the sliders.
MPG - sliders are enough better to notice but not enough better to worry about much.
After running 'em like that for a bit I eventually bought a second set of sliders.

Of note, on my old S200 even running OEM weight DP sliders eliminated the annoying dead spot it had in the 30-35 mph range.

...He said I was dead wrong. That a lighter weight roller will improve both the acceleration and the top speed.
anyway - you won't know if those weights will suit your riding style, unless you try them.
Stig

[john grinsel]

I have had 11 new maxi rubber band drive scooters, over 400,000 miles with them.  Stock, Honda/Kymco/Suzuki/Daelim   all ok, why monkey with them? Just ride  Want performance other than scooter, get a proper motorcycle

[Neil955i]

I have had 11 new maxi rubber band drive scooters, over 400,000 miles with them.  Stock, Honda/Kymco/Suzuki/Daelim   all ok, why monkey with them? Just ride  Want performance other than scooter, get a proper motorcycle

Yes, but you know with some folks, monkeying with ‘em is half the fun.  Me ? I prefer riding too.

[Stig / Major Tom]

Yes, but you know with some folks, monkeying with ‘em is half the fun.  Me ? I prefer riding too.

I was like that first 5 yrs or so....now I prefer to stay off my knees and ride it.
Fortunately I have 2 very reliable, easy to maintain scooters so I can stay off of my knees.


taught my daughter to say "don'tfoolwidit" when she was just little....
Stig

[monkeybongos]

Lighter = better acceleration and top speed (or at least no loss)?  But w higher revs?  Would that shorten the engine life?
That would explain why mfgrs don't install lighter rollers...

I'm perfectly happy w the Cali's acceleration and top speed (w stock rollers), higher mpg would make me consider sliders. 
Dealer said they were more of a racing thing.

[Neil955i]

Dealer said they were more of a racing thing.

Where engine longevity is not the main concern!

[KymcoRockr]

When I installed Dr. Pulley sliders on my Like I went 1gm lighter than the stock rollers and got better acceleration and top speed. The sliders ride higher in the variator ramps due to their shape so the belt rides higher as well.

No, they don't. And getting the belt as high as you can in the variator is not how you get the best speed or performance out of a scooter. That's your typical Youtube scooter guru tuning tip, like telling someone to use a sharpie on their variator and see how high the belt is going. Because it sounds good if you don't know anything about what's supposed to happen in a variator. What you want to do is find a roller weight, and not a slider, that allows the bike to stay in the powerband, not just under it like typical Honda/Kymco roller weight setups, and not blasting through it to the rev limiter, which happens when you use rollers that are too light, and carry the belt all the way out as the bike accelerates. Dr. Pulley sliders do well in markets where people know absolutely nothing about tuning transmissions, but aren't well regarded in Europe or by people who know about tuning scooter transmissions. The concept has been around a lot longer than Dr Pulley, and if it was better than rollers, and did what people claim, every OEM would have adopted them by now. Piaggio did, for about six months in their 850 scooter. It was a disaster. One thing their ability to last a long time does is wear variators out prematurely.  If the idea is to make a roller that doesn't wear out, why not make them out of steel? Because if the roller/slider isn't wearing, what do you think is?
If you want to learn how this stuff really works, get a good performance variator, a few sets of weights, and a couple of different contra springs and figure out how they work together, and what the best combination is for your particular riding situation. And if you take advise from someone who tells you to use two different weights in the variator, or remove half the weights, you are taking advice from someone who learned everything they know about scooter tuning on youtube or internet forums and not by putting the work in.