JCosta vs Dr Pulley sliders - specific questions!

[go.duesouth]

As I too have a DT, and it does have 30+horses from a 300cc. I'm interested in the same question as Cortez, one that nobody seems to have an answer to. Is the rpm always higher under stable cruising speed?

I also respectfully disagree with those who think the sliders do nothing, or next to it. I have the 14gr Dr. Pulley's. On my bike, they unequivocally make a marked difference. The bike is better in all aspects of acceleration and better top end cruising. Meaning, it has faster acceleration, more smooth cruising at +70mph and I haven't noticed a decrease in performance in the top end. Slightly higher around town rpm, but haven't noticed much in mpg hits.

[MODNROD]

Originally Posted by Qaz

Modnrod- Please explain what part of this I am wrong about, I am always open to learning something new. Also explain how clutch engagement can varie your rpm's at cruising speeds.

No, you're probably right man, and I didn't explain myself properly as well, which never helps.

I got the higher launch revs from the actuation springs, then I got the lower cruise revs from a combination of cam ramp rates, pillow springs AND the addition of the Dr Pulley sliders.

The J.Costa I know on the Tmax works to reduce cruise revs, probably as you have said due to the ramp rates on the variator. As the Tmax doesn't have an easy way to adjust launch/cruise revs (I don't consider modifying clutch pressure plate weights to vary lock-up an easy mod), you would have to say the J.Costa has the best of both worlds it would seem out of bolt-on bits (but I don't know coz I haven't ridden one yet, just off reports).

Sorry Cortez, I would love to fly over there and donate my time and spanners to the cause! Perhaps we could find an understanding benefactor who could help us conduct physics experiments (purely for scientific research purposes)on your bike.

[Cortez]

Originally Posted by go.duesouth

As I too have a DT, and it does have 30+horses from a 300cc. I'm interested in the same question as Cortez, one that nobody seems to have an answer to. Is the rpm always higher under stable cruising speed?

I also respectfully disagree with those who think the sliders do nothing, or next to it. I have the 14gr Dr. Pulley's. On my bike, they unequivocally make a marked difference. The bike is better in all aspects of acceleration and better top end cruising. Meaning, it has faster acceleration, more smooth cruising at +70mph and I haven't noticed a decrease in performance in the top end. Slightly higher around town rpm, but haven't noticed much in mpg hits.

+1 on everything you said.
I've dropped the 0-60mph time by 2 seconds (11 to 9 roughly) with the
sliders, and even with the topcase in the second timed run, so it's probably
more then 2 seconds difference.

How's your top speed?
Mine is still struggling to reach 90mph, and usually can't .. 86-87mph at
7600rpms is about as high as it will go, and I've ridden a test bike with 4k
miles on the clock and worn rollers that did 93-95mph @ 8600rpm.

Anyways, the difference between 15.5gr stock weights and 14gr sliders
is night and day, and I know I can get even better acceleration with 13gr
sliders, but that would mess up the cruising revs, and that just won't do.

I've asked about this on other forums too, and all I get "Yeah, jcosta is
awesome! Amazing performance!" but no one seems to answer ANY of
my questions.

[Cortez]

Originally Posted by MODNROD

The J.Costa I know on the Tmax works to reduce cruise revs, probably as you have said due to the ramp rates on the variator. As the Tmax doesn't have an easy way to adjust launch/cruise revs (I don't consider modifying clutch pressure plate weights to vary lock-up an easy mod), you would have to say the J.Costa has the best of both worlds it would seem out of bolt-on bits (but I don't know coz I haven't ridden one yet, just off reports).

The Tmax is probably setup to rev high from the factory.
The videos I've seen seem to confirm that.
Looks like a very good stock setup.

And then comes the same issue.

Take what-ever-size-weights are in the Tmax, put in 10% lighter sliders,
and you've got just what you described - better acceleration, and lower
cruising revs after about 60mph.

HOWEVER, wide open throttle with THAT particular setup will probably
rev the bike out more or less 500revs more then the stock setup WOT,
and jcosta will rev the engine up to the maximum power revs instantly.

IF jcosta keeps the revs as low as stock or dr pulley modified setup when
riding normally/cruising around town, small throttle openings and all that,
and still manages to bury the needle to the redline at any speed at WOT,
we've got a winner.

You CAN NOT make the stock variator do that.
I'd actually be surprised if jcosta did that as well.

The only bikes I'm aware of that are capable of doing that have the
electronically controlled CVT (burgman 650 and aprilia mana).

Originally Posted by MODNROD

Sorry Cortez, I would love to fly over there and donate my time and spanners
to the cause! Perhaps we could find an understanding benefactor who could help us conduct physics experiments (purely for scientific research purposes)on your bike.

Well, jump on the plane and we'll figure the rest out when you get here.

[TheReaper!]

Personally I've never checked the rpm's with stock verses the jcosta , to tell you the truth I really don't care .
I've seen no difference top end , but a huge difference on take off . Also I burn a little more gasoline , but again
I don't care about using a little more fuel . I am happy for the trade off because the performance is that much better .
The only bad thing I've ever heard about the jcosta , is from people who are to cheap to buy one .

TheReaper!

[Cortez]

Originally Posted by TheReaper!

Personally I've never checked the rpm's with stock verses the jcosta , to tell you the truth I really don't care .
I've seen no difference top end , but a huge difference on take off . Also I burn a little more gasoline , but again
I don't care about using a little more fuel . I am happy for the trade off because the performance is that much better .
The only bad thing I've ever heard about the jcosta , is from people who are to cheap to buy one .

TheReaper!

Reading what you wrote, I'm gonna say you should have bought a faster
scooter in the first place.

I don't want to blow the engine up running the bike at 7/8 of it's available
revs at all times. Don't want the fuel consumption that comes with it,
don't want the noise either.

Just want a smooth, relaxed ride, and the CVT (which is a huge compromise
to begin with re: delivering power to the ground) that's setup as good as
possible.

[Warney]

There is a fellow on totalruckus in the Big Ruckus section that has tested about every weight roller/slider combination in comparison with the jcosta. He plotted the results for reference.
http://totalruckus.com/phpBB3/viewto...7&hilit=jcosta
I think the answer you seek is there, good luck with the data.

[TheReaper!]

Originally Posted by Cortez

Reading what you wrote, I'm gonna say you should have bought a faster
scooter in the first place.

I don't want to blow the engine up running the bike at 7/8 of it's available
revs at all times. Don't want the fuel consumption that comes with it,
don't want the noise either.

Just want a smooth, relaxed ride, and the CVT (which is a huge compromise
to begin with re: delivering power to the ground) that's setup as good as
possible.

I would agree with you on that , except for the fact that I am not taking off full throttle all the time .
On the Big Ruckus the jcosta smooths out the flat spots , on the Tmax it just plain makes it even
faster on take off than it already is . If you are looking for an excuse not to buy one , you don't need
one . Stick with your same variator and play with the weights . I did that and like I said found it to be a waste of time and money . I don't care about the money spent on the jcosta or the fuel , I care about performance first .

[MODNROD]

Excellent reference, thanks Warney! Perfect!
There you go Cortez, someone HAS done the tests!

[go.duesouth]

Originally Posted by Cortez

+1 on everything you said.

How's your top speed?
Mine is still struggling to reach 90mph, and usually can't .. 86-87mph at
7600rpms is about as high as it will go, and I've ridden a test bike with 4k
miles on the clock and worn rollers that did 93-95mph @ 8600rpm.

Not sure on my top speed. Took me and my wife (both of us are approx 320lbs) on a run at about 80mph. It didn't have any problem and had a little left. It was mostly flat. I've hit 85 without any issues. The way it feels I don't think it would have a problem hitting 90+. However, the bike didn't come into it's power until somewhere between 1K-2K miles in the break in.

Let me know if you try one of the things mentioned here. I have to admit, that the 300i feels like it's in a sweet spot, so the gains would have to be something pretty noticeable. And price isn't an issue, the improvements just have to be worth the price.

[Qaz]

Cortez- The reason no one has answered your question, is because it is not a cut and dried one. There is no simple answer to your question.
This is the basic rule for scooters: The lighter the roller weight, the quicker the acceleration, but lower the top end and higher cruising rev's. In reverse, the heavier the weight, the slower the acceleration, reduced cruising rev's and potentially higher top end. These are rock hard rules to a point and that is why I question the 30+ horsepower. New rule: Torque= acceleration, Horsepower= Top end.
For the most part scooters are very efficent. They are designed to operate in a certain rev range and the cvt was balanced to operate in that range from the factory. They are trying to remove or limit the input of the rider. From the factory, that scooter is the best it can be at doing everything it was designed to do. You will not do better than the factory, if you change their set-up, you will have to give up some thing, ie.. fuel mileage, top end, bottom end, but it will be something.
Remember I said the rules were rock solid to a point. You can go too light on the weights and too heavy, neither is good. Too light and it just rev's and the scooter has very little go, too heavy and it bogs and has no go. The easiest place to learn to tune a scooter is with a 50cc 2-stroke because it operates in a narrow power band at high RPM's. The reason I say it is easy is because little changes make a big difference both good and bad quickly.
Now to answer the question you have been asking. You went the wrong way with the Dr.Pully slider. You need to go up 2 grams above the stock roller weights, so if they were 15 grams, you need to go to a 17 DP. You should have a little better acceleration and your top speed should come back.
Oh yea, why I questioned the horsepower on your scoot. The change to the variator weight that you did should not have changed the top speed that much, if you really had the horse power to pull it.

Good luck

[Cortez]

Originally Posted by Warney

There is a fellow on totalruckus in the Big Ruckus section that has tested about every weight roller/slider combination in comparison with the jcosta. He plotted the results for reference.
http://totalruckus.com/phpBB3/viewto...7&hilit=jcosta
I think the answer you seek is there, good luck with the data.

Thanks!

[Cortez]

Originally Posted by TheReaper!

I would agree with you on that , except for the fact that I am not taking off full throttle all the time .
On the Big Ruckus the jcosta smooths out the flat spots , on the Tmax it just plain makes it even
faster on take off than it already is . If you are looking for an excuse not to buy one , you don't need
one . Stick with your same variator and play with the weights . I did that and like I said found it to be a waste of time and money . I don't care about the money spent on the jcosta or the fuel , I care about performance first .

Yeah, about the bolded part, I would have kept my Kawasaki if I wanted
that, but I value smoothness and other stuff more now.

Getting old, I guess.

[Cortez]

Originally Posted by go.duesouth

Not sure on my top speed. Took me and my wife (both of us are approx 320lbs) on a run at about 80mph. It didn't have any problem and had a little left. It was mostly flat. I've hit 85 without any issues. The way it feels I don't think it would have a problem hitting 90+. However, the bike didn't come into it's power until somewhere between 1K-2K miles in the break in.

Let me know if you try one of the things mentioned here. I have to admit, that the 300i feels like it's in a sweet spot, so the gains would have to be something pretty noticeable. And price isn't an issue, the improvements just have to be worth the price.

+1

Will do!

[Cortez]

Originally Posted by MODNROD

Excellent reference, thanks Warney! Perfect!
There you go Cortez, someone HAS done the tests!

Never figured there's someone that'll do that, but I would.