KymcoForum.com
Scooters - 125 to 300 => Downtown 300 => Topic started by: stuo on April 04, 2019, 08:52:21 PM
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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?
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Con. Then it will be wound up tighter at cruise, tighter than a gnat stretched over a banjo!
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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
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Outstanding, de dee! That's my Rx! I'll report back with the results....
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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.
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Lighter weights are going to give you what you are looking for.
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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?
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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.
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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!
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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...
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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?
(https://i.postimg.cc/rmgykzw9/P1020725-1.jpg)
Stig
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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.
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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 combustÃvel 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?
(https://scontent.fgig4-1.fna.fbcdn.net/v/t1.0-9/54728143_1052982044886832_1547891636359397376_o.jpg?_nc_cat=104&_nc_ht=scontent.fgig4-1.fna&oh=17ec5fff07d78f9500153f7f92889e1d&oe=5D4ECED3)
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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
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Dremel + small weigh scale!
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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 combustÃvel 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 did my own grinding to modify the variator pulley with a 1/2 " band sander, now I see Malossi has made the same modify to there vaiator, as you get more range on the variator you have lower RPM and less power for top speed, is your top speed by the speedometer , or on a GPS,. 168 Kmh. wow,!!!
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?
(https://scontent.fgig4-1.fna.fbcdn.net/v/t1.0-9/54728143_1052982044886832_1547891636359397376_o.jpg?_nc_cat=104&_nc_ht=scontent.fgig4-1.fna&oh=17ec5fff07d78f9500153f7f92889e1d&oe=5D4ECED3)
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How about TechPulleys?
They are supposed to be the next generation of 'sliders'.
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How about TechPulleys?
They are supposed to be the next generation of 'sliders'.
Can you post a link to TechPulleys? Not finding it.
Thanks
S6
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There you go Stig.
https://www.techpulley.com (https://www.techpulley.com)
Can you post a link to TechPulleys? Not finding it.
Thanks
S6
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There you go Stig.
https://www.techpulley.com (https://www.techpulley.com)
Thanks!
Oh yeah, have seen those before.
Stig
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So what makes them any better?
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;D ;D ;D :D
2011 downtown 300i., 87,000 Km. so far., removed the Shendengen SH 232-12 7.3 reg . because it was putting out 18 volts installed a reg - 14 ked9 d406 , it is much lighter in the fins for cooling started up ran for a hour then quit checked the reg it was very hot, I will try it again after it cools, to see if it runs again, put the diagnostic on it and all looks normal, wish I new more about diagnostics read outs,. I can build a house but electronics is over my head,
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;D ;D ;D :D
2011 downtown 300i., 87,000 Km. so far., removed the Shendengen SH 232-12 7.3 reg . because it was putting out 18 volts installed a reg - 14 ked9 d406 , it is much lighter in the fins for cooling started up ran for a hour then quit checked the reg it was very hot, I will try it again after it cools, to see if it runs again, put the diagnostic on it and all looks normal, wish I new more about diagnostics read outs,. I can build a house but electronics is over my head,
it started up like it was a new scooter, did not ride it as the rain is falling with hail we are getting snow again to night, spring may be next month???? no flowers showing, to cold ,.
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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?
Looks like another way to have more RPM (and more power) at lower speeds would be to install shims between the variator bush, and outer half of the variator pulley. Complete sets of different size variator shims are available for other model scooters, maybe complete sets of shims will be available for these models as well ?
By using shimms at the Variator, the slightly wider variator pulley actualy allows the belt to be at a lower position - and allows the belt to be in a higher position at the clutch pulley during take off. This obviously will cause more RPM, and more power during take off.
The only downfall though - aparently top end speed seem to be lower after a modification like this.
Care must also be taken that not too many shimms are used - when the pulley becomes too wide, the belt will start getting in contact with the center bush, and the belt will start slipping.
I think modifications like this might work quite well, but special care must be taken not to use too many shimms. The reason being - when the belt starts getting worn, (thinner) the pulley might be too wide, the belt will start rubbing against the bush, and the belt will start slipping.
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So what makes them any better?
Marketing. Again, companies like Honda, Yamaha, Kymco, etc do have R and D departments. And by now someone probably told someone who works at one of these companies about Sliders. Those companies may have even tried to develop a better design than the classic roller. It's a fairly cheap part, and if it gave their models an advantage, they probably would have considered adopting a different design. 20 years before Dr. Pulley a company in Italy started selling a slider. Despite how much better they are than rollers on the internet, every single scooter manufacturer in the world doesn't use sliders in their new bikes. None of the manufacturers of performance variators that have an active racing program use sliders.
One thing to consider when tuning your variator is that the ability to get out of the way quickly is as important to your safety as the ability to brake properly. When you try to lower the rpms at a given speed, you give up some of that ability.
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The rollers arrived and six were perfect at 13.0 grams, one was 12.9, one was 13.1. I'm very slow these days but I will post the results after switching them. Despite my increasing dementia the current RPMs and speed are easy to remember: 7000 revs @ 70mph, 6000 @ 60, 3000 @ 30, etc.
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6 yrs ago I was told that sliders "act lighter", so the advice was to go 1 or 2 gm heavier.
But....not knowing this....
I weighed my stock rollers at the Post Office, ordered the 1gm lighter and did not at all like the higher revs at my 35mph cruising. Tossed those Dr P's and went 1gm heavier than stock....and have enjoyed them for 5.5 yrs since.
Stig
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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 combustÃvel 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?
(https://scontent.fgig4-1.fna.fbcdn.net/v/t1.0-9/54728143_1052982044886832_1547891636359397376_o.jpg?_nc_cat=104&_nc_ht=scontent.fgig4-1.fna&oh=17ec5fff07d78f9500153f7f92889e1d&oe=5D4ECED3)
I did not buy any parts , I modified the viator to my liking , ending up the same as malossi variator, but as you lower the RPM. your top speed will lower too, because you will not be in the RPM. for top power,.
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I did it: I replaced the stock 15.4 gram rollers with 13 gram rollers. The difference in acceleration is incredible: no more flat spot off the line! And I don't seem to have lost anything on the top end, 6000 RPM at 60mph, 7000 at 70 and 7500 at 80, with plenty more oomph available if needed. I also sanded the clutch pads with 220 grit and got rid of the "grabbies". I'm in love with my new scoot!
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Well I wasnt aware of the roller weights, I just ordered what was specified and received 14g weights. Once I had changed them out and weighed the old ones I discovered the old ones were 15.5. So my question is this: will I hurt my scooter drive train using these 14g's until I get the proper 15.5's or do I need to remove them and put the old ones back in until my new ones arrive. After 41000 miles the original rollers had flat spots so I figured while changing out the belt I'd update my rollers. Is there any danger to my bike as I usually ride at a 65 mph clip most of the time. Yes I've read many posts about the rollers but I am still confused as to whether or not there is a danger to the bike.
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Did you notice you're running at higher RPM's now per your road speed?
Stig
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Looks like another way to have more RPM (and more power) at lower speeds would be to install shims between the variator bush, and outer half of the variator pulley. Complete sets of different size variator shims are available for other model scooters, maybe complete sets of shims will be available for these models as well ?
By using shimms at the Variator, the slightly wider variator pulley actualy allows the belt to be at a lower position - and allows the belt to be in a higher position at the clutch pulley during take off. This obviously will cause more RPM, and more power during take off.
The only downfall though - aparently top end speed seem to be lower after a modification like this.
Care must also be taken that not too many shimms are used - when the pulley becomes too wide, the belt will start getting in contact with the center bush, and the belt will start slipping.
I think modifications like this might work quite well, but special care must be taken not to use too many shimms. The reason being - when the belt starts getting worn, (thinner) the pulley might be too wide, the belt will start rubbing against the bush, and the belt will start slipping.
No expert here on 50cc scoots, and derestricting of same, but I think I've read that yes, these scoots are often 35mph speed restricted from the factory by use of a shim in the front pulley.
To derestrict this shim is removed to increase top speed a bit. Not sure what that would do to the 'grunt' of a 50 trying to get away from a light in traffic?
Stig
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And not sure that manufacturers are always working that hard to stay out front. With rollers or sliders. Honda doesn't even publish HP ratings most often - and to my knowledge has never been known to be the performance leader of the Big 4 from Japan. They do quite well selling bullet-proof - not boy-racer.
Most companies had to be forcefully dragged into releasing bikes and scooters with ABS - long after it was standard on automobiles. The same with EFI, disc brakes, better lights, etc.
My lowly 7 year old Toyota product came with 4 Denso Iridium spark plugs - but yet to see them in a bike.
Sliders give the owner a quick and simple method of slightly changing the way his scooter behaves. Nothing to get angry about - they're not expensive & they do outlast rollers and those who sell them have printed guides for taking some of the mystery out of what to expect from them.
Sliders very likely have more of an impact on 4-stroke scooter performance than any after market pipe.....yet few get exercised about these pricey, louder, generic cans.
Stig
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Wow 168 kmh. Geeez how you do that! I was getting about 135kmh only and of course loss about 10 kmh recently.
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No expert here on 50cc scoots, and derestricting of same, but I think I've read that yes, these scoots are often 35mph speed restricted from the factory by use of a shim in the front pulley.
To derestrict this shim is removed to increase top speed a bit. Not sure what that would do to the 'grunt' of a 50 trying to get away from a light in traffic?
Stig
It's a spacer, like a ring around the bushing or boss, that is used to keep the pulleys from closing all the way. Kymco uses a boss, or bushing that has the restriction machined into it. You can't just pull something out, you have to replace something on their scooters.
If you use shims to make the variator boss or bushing wider (which is what they do when they try to tune it that way), you do lose top speed because the belt will be lower at the same rpm, once you max out. If you use enough of them, you can't get the nut on all the way, and we all know that never turns out well.
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I went with 1gm lighter Dr P sliders in my 163cc LIKE...
(https://i.postimg.cc/rmgykzw9/P1020725-1.jpg)
Stig
Great photo with the truck in the background.
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It's not necessarilllyyy that simple - if he goes a bit lighter, t...
In my GV250 I changed to Dr Pulley 19x23mm 19g flat weights, and sliders (3) at 10K miles and now I have 28K and they are still running great. If I want more hp/torque I twist the throttle. Was never interested in changing the weight to make the motor rev higher than it normally does on the highway which is between 8-9K RPMs.
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my 2 stroke SH50
Now you're talking. We never got it in the US.
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Just want to make sure is roller dimensions are correct:
20mm outer diameter
12mm width
OEM weight is 15,5 gr
and then we play around with lower weights to get more acceleration from zero and at lower speeds ?
thanks
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Con. Then it will be wound up tighter at cruise, tighter than a gnat stretched over a banjo!
Guys, I am far from the scooter tuning expert, but here's a link to a thread with some actual data from various variator/roller weight configurations on a Honda ADV 150. The model being discussed here isn't important so much as the numbers. As you can see, with an aftermarket variator, paired with rollers of varying weights, you can fine-tune how the power from your engine is delivered through the CVT. And interestingly, while most of these "experimental" setups resulted in a MODEST INCREASE in RPMs at lower speed/acceleration, they actually slightly INCREASED TOP SPEED while slightly DECREASING RPMs at top speed.
https://www.hondapcx.org/viewtopic.php?f=45&t=11524 (https://www.hondapcx.org/viewtopic.php?f=45&t=11524)
Of course, I am taking the poster at his/her word here. But to me, this looks promising enough to at least consider an aftermarket variator/roller combo at some point in the future. I can get a Yuminasi variator and roller set for my scoot for less than $150, which isn't a huge investment by any means. And, as others have already said, if for whatever reason I decide I don't like it, it's an easy job to simply re-install the stock components.
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I'll just add that I recently changed my Kymco OEM rollers for a set of Dr Pulley sliders in 13 gram (1 gram lighter than stock). Now, granted, I changed a few other things as well (new belt, cleaned and regreased driven pulley, new contra spring) but my scoot now leaves stop lights like a bat out of h*ll!
It was always fairly quick off the line but I can now smoke most of the cars. I keep waiting for my front tire to come off the ground! My top speed didn't decrease any, either. In fact, it seems to be up a bit but that could be due to the other items I changed.
As far as rpm while riding at a similar speed? Who knows...I don't have a tach and I ride with ear plugs and bluetooth music playing in my helmet...but it doesn't feel like it's spinning any faster.
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Maybe my 2 cents.. I did some testing in this subject
https://www.kymcoforum.com/index.php?topic=30655.msg215843#msg215843
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I've had pretty good results with the Tech Pulley flying rollers 14 gr.