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Dr Pulley - the best medicine!

Discussion in 'Scooters' started by mark59, Nov 19, 2013.

  1. Just replaced the stock 11gm rollers on my TGB101R 150cc for a set of Dr Pulley 10.5gm sliders.

    An amazing difference to both acceleration AND top speed. In fact, mid-range acceleration has been given a sizable boost too.

    When you've only got 10bhp to play with you need all the help you can get. ;)

    I'm getting sets of 8g and 9.5g also to see just how fast off the mark the even lighter weights can make the little buzzer. I ride 50k every day through Melbourne peak hour arterial traffic so I'd happily trade off a bit of the 100 kph top speed for a faster blast off the line.

    It might gain even more top speed if this info below from a Dr Pulley specialist in the USA applies even at low slider weights.



    For your info if you are interested :
    Sliding Roller Weight ( US7276004 ) vs. Round Roller

    People know that the round roller weight is not always "rolling" in the ramp (the runway for the roller ); actually the movement of RR (round roller weight) is a hybrid movement "rolling & sliding".

    The features of Slider (sliding roller weight, or SR) are:

    1. The shape of Slider is designed to

    i. make its initial low position lower than that with stock round roller. So the low gear becomes much lower and therefore able to get a higher acceleration;

    ii. form the flat front side of Slider, which enables the Slider move more outward than round roller does. Therefore, V-belt moves much higher; i.e., the high gear becomes much higher to get higher top end.

    iii. Thus, the take-off rpm with Slider is about 300~500 rpm higher than that with round roller, and the top end rpm is 300~500 rpm lower than that with round roller.

    Consequently the Slider can make the range of gear shift become broader.

    2. Through the physics view, the work needed to move the Slider (from bottom to top position) is 2 x F (force) x S (distance of ramp) while the work needed to move the RR is 2 x F (force) x S + 1/2 x M V2,

    This shows the movement of Slider is faster than RR.

    3. The Slider is molded from material SL-9T (self-lubricated polyamide 46 ), which has low friction of coefficient, high wear resistance, high heat resistance and contains no abrasive filler (do not wear aluminum-made variator).

    So, the durability of Slider is excellent.4. The stability of gear shift ratio of SR is much better than the Round Roller
    that means the fade of CVT performance is much less for SR.

  2. wow... now here's a thread that is gonna go awry.

    i'll kick it off. it may dull the pain but if you do it too much you'll go blind.
  3. Great to see you're interested in scooters too!
  4. What did I just read?
  5. Gotta be honest, I didn't really understand much of the original post.

    I thought that you could fiddle with roller weights and either get better acceleration, or higher top speed, but not the two together.

    I dunno what's in the Gilera, but the owner told me is was set from more acceleration and less top end.

    Since I really don't know very much about modern CVT scooters, I have no idea how big a job it is to first pull out the current rollers and weigh them, then to get replacement rollers and/or sliders and try them.

    Any hints?

    Is it major work?
  6. The CVT is a very mechanical device with plenty of opportunity for tuning. There are lots of videos on YouTube to get some detailed instructions.

    Here is a link to explain the difference between sliders and rollers:

    Here are a couple of videos on how to change the belt and sliders/rollers on a GY6 scooter:

    You can make the variator holder from materials readily available at your local hardware. The rattle gun is a must!

    Scooter tuning can also involve swapping out with the clutch springs and the big spring that separates the two halves of the clutch pulley. Bang for buck replacing the rollers with sliders will improve the performance of the scooter's acceleration and top end speed. Messing about with other springs and things can actually cancel out the positive effect the sliders confer (unless you really know what you are doing - which I of do not :D)

    Lighter weight rollers tend to improve acceleration and heavier weight rollers tend to improve top end speed. Sliders achieve both due to their weight, rapid mobility in the variator and profile.

    I'd also recommend a higher performance Gate belt to match the higher performance of the CVT overall. I just hate it when my rubber breaks (just to continue the earlier theme!).

    Of course, this all mysterious B.S. to motorbike riders so I do apologize for any confusion and consternation - though I did see that this was a dedicated Scooter forum.


    • Informative Informative x 1
  7. First of all, I'm a cheap tart and will ride anything that is two wheeled and fun and I don't have to pedal.

    Mysterious, yup, 'cos back when I last rode a scooter they had pukka gears to shift and a clutch.

    BS, no, I don't think so, and I thank you for the pointers.

    The biggest problem I have with the 180 Runner is that I just don't know exactly what has been done to it.

    I know it has a Malossi barrel, piston and head, a bigger than standard carbie, a trick expansion chamber, and something non-standard in the transmission.

    OK, I can see how to make up the holder thingy, but I haven't got a rattle gun.

    Having viewed the videos, it's now making a wee bit more sense to me.

    Thanks for your help, Mark.
  8. I need to get a life.
    I'm sitting here reading about how to hot up a scooter:(
    • Funny Funny x 1
  9. Hot scooters can be a bucketload of hilarious fun at moderate speeds if approached with the right attitude. I hope so at least, given that there may be a Suzuki AN125 or similar in my nearish future.
  10. Our local MC club is holding a 6 hour TT scooter race in January.
    Should be good for a larf.
  11. Brilliant thanks very much for this video
  12. Iv got the 101R 125 scooter now will be getting Dr pulley
    • Like Like x 1
  13. Yea the video healp me out did my little 50 cc scooter and couldn't find any information on wich way the nut turned and finely got it undone but was the wrong way ofcuse an striped it so then put the new bealt on but had to weild the nut back on. But it only lasted 2 weeks an had to get another motor and got one thank God. But now was glade for the video
  14. Thanks you guys now I can make a holder like I saw in the video to undo the cluch an v pulley
  15. Yea 125 not to bad you would want any smaller
  16. get your hand off it Michael
  17. Mark,

    How did you go with the different weight sliders ?

    Was there a weight sweet spot ?

    What was the difference in acceleration, top speed, rideability, getting off the mark, and fuel economy with the different weights ?

    I'm definitely interested to hear how you got on, as I'm planning Dr Pulley sliders and an HiT clutch at the next service when the belt is changed on my 250 Burgman.
  18. For the benefit of anyone coming to this thread and looking for info on Dr Pulleys sliders, I fitted a set (of the recommended weights) to my MP3 250 and an very happy with the result.

    The low speed rattle has gone.

    Acceleration feels a tread more brisk and it revs about 500 rpm higher under load. I'm not sure about the top end except that I still have enough :)