Lighter rollers?

[stuo]

I'm considering lightening the stock rollers on my 2011 DT300 to have more RPM at lower speeds. Has anyone out there done it?

Opinions pro and con?

[CROSSBOLT]

Con. Then it will be wound up tighter at cruise, tighter than a gnat stretched over a banjo!

[de dee]

stock rollers are 15 .5 grams  ,.  you could try Dr. pulley  sliders 20/ 12    14 gram , that worked well for me , 

  higher RPM starting,  then lower RPM at speed,  then I liked riding at speed with low RPM.,  I modded the variator to match the malossi variator  I found out 5 years later,.  I can ride at 65 MPH. at 6,000 RPM, and some-times as low as 5,000  RPM, with no head wind

[stuo]

Outstanding, de dee! That's my Rx! I'll report back with the results....

[stuo]

Karl, your "con" is valid, but I'm willing to give up on the top end for more torque at lower speeds. Anyway, it is an easily reversible experiment.

[KymcoRockr]

Lighter weights are going to give you what you are looking for.

[Viper254]

Con. Then it will be wound up tighter at cruise, tighter than a gnat stretched over a banjo!

It's not necessarilllyyy that simple - if he goes a bit lighter, the rollers will be thrown out a little higher in the rev range - hence the higher RPM through the "range". But if the rollers are still being forced to the extremes of the variator at high revs, there's no theoretical change to top speed - just how you get there and the fuel consumption of revving higher to get to that point. Does that make sense?

Problems occur when people put in roller that are too light - and there isn't enough centrifugal force generated from the engine throwing out the light rollers to push the variator out to it's fullest gearing. Then, in those circumstances, you can lose top speed.

Dee dee's Dr. Pulleys are lighter, but the shape of them mean they're deeper when pushed to the extremes, so you can use the slightly higher revs to push the lighter rollers out in the variator, but when they're pushed to the extreme of the variator, the different shape means you're able to attain a more extreme gearing that isn't possible with cylindrical rollers. Does that make sense?

[KymcoRockr]

Except that it doesn't really work that way, or you would see people who know what they are doing when it comes to tuning a variator, use them. All the big companies would be using their own version of sliders. But they don't. If your entire experience tuning scooters is reading the internet, then putting in slightly lighter sliders, they seem to do amazing things.
But on the internet you are treated to much information that doesn't make sense if you really think about  how a variator should work best. The whole draw a black line with a sharpie concept is useless from a performance standpoint, because for your engine to work it's best, you don't want the belt as high up on the variator as you can get it.

[Viper254]

Except that it doesn't really work that way, or you would see people who know what they are doing when it comes to tuning a variator, use them. All the big companies would be using their own version of sliders. But they don't. If your entire experience tuning scooters is reading the internet, then putting in slightly lighter sliders, they seem to do amazing things.
But on the internet you are treated to much information that doesn't make sense if you really think about  how a variator should work best. The whole draw a black line with a sharpie concept is useless from a performance standpoint, because for your engine to work it's best, you don't want the belt as high up on the variator as you can get it.

Bingo!

[stuo]

Great comments!

I ordered a set of 13 gram rollers, not sliders, because I don't want to introduce an extra variable to this experiment. I will report back with the results.

Stay tuned, don't touch that dial...

[Stig / Major Tom]

I went with 1gm lighter Dr P sliders in my 163cc LIKE - but quickly disliked the higher revs at my 30>45mph cruising.
Pulled them out and went with stock weight but still Dr P sliders.....5 or so years ago.
I like them - but never did drag race times or Top Speed tests to see what changed.

I like to poke along - enjoying the cow poop and wood smoke.
Haven't tried a Top Speed run in memory. I did stop pretty quick once the other day - does that count?



Stig

[Viper254]

I also removed sliders from my Like, though they weren't Dr. Pulley ones. They gave a strange progression through the rev range.

Case in point, expanding on KymcoRockr, who is right - my 2 stroke SH50 that I've just got running. It's got a definite power band, and the rollers that are currently fitted are too heavy - the variator is being pushed out at too low revs, before I really have any power to push the bike along, making it reaaaaally slow up hills. However, if I lighten the rollers a touch, hopefully I can raise the revs at which the variator is pushed out, to make better use of the power distribution from the teeny engine.

[fabiopasche]

stock rollers are 15 .5 grams  ,.  you could try Dr. pulley  sliders 20/ 12    14 gram , that worked well for me , 

  higher RPM starting,  then lower RPM at speed,  then I liked riding at speed with low RPM.,  I modded the variator to match the malossi variator  I found out 5 years later,.  I can ride at 65 MPH. at 6,000 RPM, and some-times as low as 5,000  RPM, with no head wind

Eu moro no Brasil e n tenho facilidade em adquirir peças para essa modificação

Comprei rolos de 15G e atingi 168 KMH de velocidade final m as gostaria de ter a RPM reduzida para economia de combustível mas com velocidade final maior ..

Como você na sua scooter e onde comprou as peças ?



I live in Brazil and I can not easily buy parts for this modification

I bought 15G rolls and reached 168 KMH of final speed but I would like to have the RPM reduced for fuel economy but with higher final speed ..

Like you on your scooter and where did you buy the parts?

[stuo]

I ordered the rollers from ebay but got 13 grams, not 12. They come from Taiwan.

//www.ebay.com/itm/SET-of-8-ROLLER-WEIGHTS-20x12-for-KYMCO-DOWNTOWN-200i-12g/401223911461?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[CROSSBOLT]

Dremel + small weigh scale!