BlackJack and Dr. Pulley sliders

[HowHH]

Hi all. Recently picked up a BlackJack, and this is my first question about it.

I have a 2009 BlackJack with approximately 3500 miles. Good acceleration and top end, the only issue I've been having is difficulty feathering the throttle for low-speed maneuvering. When slowly rolling on the throttle, instead of gradually moving forward the scooter would just sort kick in when the transmission engaged. Not so good for low speed maneuvering. No complaints though when I want to quickly accelerate.

While lurking on this forum, I've been reading about the Dr. Pulley sliders, I thought I'd give them a try. People and do things to say about their smooth acceleration. I ended up getting the 11 g sliders, which a lot of people seem to use. Initial throttle response is now smoother, but acceleration does not seem to be as brisk. I haven't tried out the top end speed due to the roads being a little wet yesterday.

I brought the old weights into work today, weighed them on a high end electronic postal meter, and found out that the old rollers weighed in at 13.8g.

I'm concerned that maybe I went too low in weight on the sliders. If my goal is to retain the overall quick acceleration of the BlackJack with the original rollers, but to have better low-speed control would I be better off with the 13g or 14g weight?

[killbilly]

I'm certainly no authority, but I've been investigating similar things recently.

Three separate people (all of whom I would consider knowledgeable) have told me that going down more than 1-gram with everything else stock will have diminishing returns.

The Blur, for example, has 14g weights. I'm considering dropping to 13g to see how it is. From there, I'll consider a competition clutch, which may alter my slider weight again.

[HowHH]

To could the waters even more, I just found the following link on the Scooterworks website:

http://www.scooterworks.com/wiki/roller_sizes.ashx

that lists the stock roller weights for the Blur 150, BlackJack, and Buddy 150 as being 13.0g

If 13.0g is the stock weight per Scooterworks, how do I get 13.8g in the BlackJack, and killbilly 14g in the Blur? Variation in the production run??

[Tocsik]

The Blur he has is the 220i so I don't think the comparison is equal. Heavier bike that will feel different from the Buddy no matter what.

The Blackjack already comes with an upgraded variator and with only 3500 miles it sounds like you may just have belt dust build-up if you are having rough movement at lower speeds. Did you blow out the variator and clutch while you had the cover off?

Basically, lower weight rollers/sliders give better acceleration while heavier weights give better top end. I wonder if the lighter weights are providing more low-end torque making the low-speed maneuvering more difficult?

[HowHH]

Actually, I'm getting smoother low end performance with the 11g sliders than with the stock rollers. But it does feel like I lost some oomph in full-on acceleration (which does seem different from what others have observed).

I did clean everything out when I had the case open. The rollers were pretty dusty so could have been sticking. But I'm still left with the dilemma about proper weight size for stock. Scooterworks lists (on the link above) 13g as stock for the BlackJack, but this doesn't fit with the discrepancy of my roller weights coming in at 13.8g.

[Kaos]

The Blur he has is the 220i so I don't think the comparison is equal. Heavier bike that will feel different from the Buddy no matter what.

The Blackjack already comes with an upgraded variator and with only 3500 miles it sounds like you may just have belt dust build-up if you are having rough movement at lower speeds. Did you blow out the variator and clutch while you had the cover off?

Basically, lower weight rollers/sliders give better acceleration while heavier weights give better top end. I wonder if the lighter weights are providing more low-end torque making the low-speed maneuvering more difficult?

The blackjack's variator is the stock one, same as in the Buddy 125 and 150.

13.8g sliders seems actually kinda on the heavy side, I'd say maybe 12's would have been a better bet on the BJ. The 11's work really well in a 125, but the stock weights on the 125 are 11.5g anyway.

[Tocsik]

The Blur he has is the 220i so I don't think the comparison is equal. Heavier bike that will feel different from the Buddy no matter what.

The Blackjack already comes with an upgraded variator and with only 3500 miles it sounds like you may just have belt dust build-up if you are having rough movement at lower speeds. Did you blow out the variator and clutch while you had the cover off?

Basically, lower weight rollers/sliders give better acceleration while heavier weights give better top end. I wonder if the lighter weights are providing more low-end torque making the low-speed maneuvering more difficult?

The blackjack's variator is the stock one, same as in the Buddy 125 and 150.

13.8g sliders seems actually kinda on the heavy side, I'd say maybe 12's would have been a better bet on the BJ. The 11's work really well in a 125, but the stock weights on the 125 are 11.5g anyway.

Huh, I thought the BJ came with the NCY variator along with it's other goodies.

[Kaos]

The Blur he has is the 220i so I don't think the comparison is equal. Heavier bike that will feel different from the Buddy no matter what.

The Blackjack already comes with an upgraded variator and with only 3500 miles it sounds like you may just have belt dust build-up if you are having rough movement at lower speeds. Did you blow out the variator and clutch while you had the cover off?

Basically, lower weight rollers/sliders give better acceleration while heavier weights give better top end. I wonder if the lighter weights are providing more low-end torque making the low-speed maneuvering more difficult?

The blackjack's variator is the stock one, same as in the Buddy 125 and 150.

13.8g sliders seems actually kinda on the heavy side, I'd say maybe 12's would have been a better bet on the BJ. The 11's work really well in a 125, but the stock weights on the 125 are 11.5g anyway.

Huh, I thought the BJ came with the NCY variator along with it's other goodies.

No, the only engine performance change is the pipe, all the other goodies are in the suspension.

[HowHH]

13.8g sliders seems actually kinda on the heavy side, I'd say maybe 12's would have been a better bet on the BJ. The 11's work really well in a 125, but the stock weights on the 125 are 11.5g anyway.

Assuming the 13.8 measurement is accurate (and I'm going to try measuring on another scale on my way home today), and assuming I want to keep close to stock performance but with the additional smoothness of the sliders, would you expect any noticeable difference between 13, 13.5 or 14g weights. I know, this probably seems a little too obsessive

[Kaos]

13.8g sliders seems actually kinda on the heavy side, I'd say maybe 12's would have been a better bet on the BJ. The 11's work really well in a 125, but the stock weights on the 125 are 11.5g anyway.

Assuming the 13.8 measurement is accurate (and I'm going to try measuring on another scale on my way home today), and assuming I want to keep close to stock performance but with the additional smoothness of the sliders, would you expect any noticeable difference between 13, 13.5 or 14g weights. I know, this probably seems a little too obsessive

I'd think you'd notice a difference with the 13's, but likely not a real big one with the 13.5's and 14's. I know that a 1/2g difference IS noticeable though.

[HowHH]

I'd think you'd notice a difference with the 13's, but likely not a real big one with the 13.5's and 14's. I know that a 1/2g difference IS noticeable though.

Ideally, I'd like same or quicker acceleration, same top end, but mainly I'd like smoother more controllable low end performance, while continuing to retain the pop I had with the original weights when I need it. You think the 13g would give me that? (It would be fun/interesting to try 'em all, but that could get pricey!)

[Lostmycage]

You should have noticed a difference.

Did you install them in the exact orientation as the diagram says that came with them? At a quick glance, they can look symmetrical, but one flat side is longer than the other. If they're not installed correctly, they can cause a reduction in performance similar to what you're describing. There's the possibility that all of them are installed the wrong way... the design would make the variator work more smoothly than worn rollers, but you'll notice a loss in power delivery.

[Kaos]

I'd think you'd notice a difference with the 13's, but likely not a real big one with the 13.5's and 14's. I know that a 1/2g difference IS noticeable though.

Ideally, I'd like same or quicker acceleration, same top end, but mainly I'd like smoother more controllable low end performance, while continuing to retain the pop I had with the original weights when I need it. You think the 13g would give me that? (It would be fun/interesting to try 'em all, but that could get pricey!)

I'd likely try the 13 for that. It should be about right. If you want to play a bit, a 12.5g might be a good fit as well.

[HowHH]

Did you install them in the exact orientation as the diagram says that came with them?

They look to be exactly as the supplied diagram. I also checked with the tutorials available here and elsewhere.

I'll probably give the 13g a try, as Kaos suggested, as it is close to what I have measured and seems to be a good compromise, but I'll probably run the 11g for a few days just to fully check them out. If I go 13g I'll update here.

The upside of this project is the new impact wrench , so no more knuckle busting on any new frozen nuts or bolts I come across, but I think I need some type of variator holding tool as my strap wrench doesn't seem to to get a good grip when I'm torquing the variator bolt back down.

[HowHH]

Quick update. The stock BlackJack rollers are 13g. At work I used a unit conversion site to convert oz to grams. Just a random site on Google (convertunits.com). When I got home I plugged in the same weight in ounces into my Palm TX unit conversion app (U2U) and got a different result, which I verified. I thought that maybe I had input the wrong numbers on the convertunits.com site, but when I re-checked I received the same incorrect answer. Serves me right for being too lazy to pull out a calculator and doing the conversion myself!

[zsno]

13.5g Dr. Pulley's seem to be the ticket for me. Had them in there before and after all my engine mods.

[hairball]

I threw 12G sliders in my BlackJack and love it! Everything is better - Take off, Revving up to speed and top end.
BTW - I am running a stock exhaust, NOT the Prima and 65 mph is not a problem.

I weigh in at 160 pounds, I am sure rider weight makes a difference in which weight sliders you choose.

Stock sliders 4 of them were 13g, 2 were 12.5g

[Mikie M.]

Usually, the best place to start is one gram lighter than stock. If your OEM rollers are 13 gram then try 12 gram sliders. If, however, you are a very heavy individual then you might try 1.5 to 2 grams less.
For a higher top-end speed try stock weight sliders.
With sliders that are one gram less than stock, take-off should only be marginally better but mid-range acceleration should improve noticeably. A very slight increase in top-end speed may also be seen.
With one and one half, to two grams, take-off should improve quite noticeably, but mid-range and top-end will suffer a bit.
Regardless of which weight you finally settle on, DP sliders are the best first investment you can make toward better performance for your scooter.

[HowHH]

I ended up going for stock weight 13g rollers (NCY). Everything is much improved compared to the worn rollers (and the 11g Dr Pulley sliders - those were just too light. Next time round I'll try a 12g slider setup). I did make a homemade variator tool to hold the variator in place so it could be properly torqued.