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Post by ThomasTPFL on Jan 18, 2019 15:23:30 GMT -5
I'm interested in how folks that are legit in a straight line for x feet drag racing, or sprints for you English types, set up your bikes. Like clutch tuning and such.
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Post by lilpinny on Jan 18, 2019 16:11:24 GMT -5
I configured my 170 for fast takeoffs at stop lights... as close to drag racing as I get. I left the stock 150 GY6 gears on, performance varilator and drive face, heavy 13g sliders, racing clutch, removed all excess weight 9center stand, all plastics), tuned with an AFR.
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Post by snaker on Jan 18, 2019 17:36:44 GMT -5
If your setting up a machine solely for drag racing you might consider removing the Torque Sensing(TS) function by modifying the driven pulley from angled slots to linear (parallel to the shaft).
The TS is reactive.
The machine has to roll a bit before the TS starts to resist the upshifting.
That is what gives the feel of a initial bog and then a engine rev up at launch.
There would be time to save if the CVT were tuned without TS and the launch upshifting delay were removed. Regular riding would suffer though. |
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MustashMike
Scoot Member
Still alive & well
Posts: 89 
Location: Indianapolis
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Post by MustashMike on Jan 19, 2019 20:54:17 GMT -5
A good starting place is to state what scoot (4T / 2T) and displacement if you want specifics. Back in the day when the North American Scooter Racing Association (NASRA) was doing organized bracket racing, the 2 stroke folkes had their formula, and the 4 stroke camp had their own.
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Post by ThomasTPFL on Jan 19, 2019 23:31:52 GMT -5
A good starting place is to state what scoot (4T / 2T) and displacement if you want specifics. Back in the day when the North American Scooter Racing Association (NASRA) was doing organized bracket racing, the 2 stroke folkes had their formula, and the 4 stroke camp had their own. Well, I did post in 2 stroke performance, lol... i guess small stuff, 50/70cc type engines. |
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Post by Lucass2T on Jan 20, 2019 3:13:31 GMT -5
What exactly are you looking for information wise?
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MustashMike
Scoot Member
Still alive & well
Posts: 89
Location: Indianapolis
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Post by MustashMike on Jan 20, 2019 11:31:35 GMT -5
You are still so vague. Is this going to be a “sometimes” racer or dedicated “track only” project? What mill are you planning to use?
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Post by 90GTVert on Jan 20, 2019 11:40:20 GMT -5
I don't actually drag race, but I try to race everyone at red lights. You can watch a vid like THIS ONE to get an idea. The Malossi OR kit was a big deal for getting up to revs quickly off the line. It does so well that I'm using stock clutches and often soft springs on an engine with a tuned pipe. It's not fast because I'm 300lb, but it will wheelie and would prob go pretty hard for what it is with a lighter rider. |
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Post by benji on Jan 20, 2019 12:34:18 GMT -5
You are still so vague. Is this going to be a “sometimes” racer or dedicated “track only” project? What mill are you planning to use? he was actually asking about what other people are using in drag racing, he wasn't being vague. |
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Post by lilpinny on Jan 20, 2019 12:53:05 GMT -5
Like I said before, my bike is all about crushing cars off street lights. I live in Texas where the speed limit on the main road out of my neighborhood is 65mph. It also gets backed up during rush hour with cars at a standstill. I can do 65, but it helps to beat them off to the line and be first to the next line of cars... Which of course being from CA I lane share up to the light. Then repeat until I'm at my street.  . Being nimble beats top speed. All that stuff... Exhaust, springs, transmission, etc. Anything other than the stock gears actually slow takeoff down. Heavy weights. |
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Post by oldgeek on Jan 20, 2019 17:40:30 GMT -5
I'm interested in how folks that are legit in a straight line for x feet drag racing, or sprints for you English types, set up your bikes. Like clutch tuning and such. I am not a dragger but like others here I often race from light to light. With my 70cc streetrace kitted mina I was always changing the CVT in an attempt to get a good launch. The total weight of the scoot + rider is a HUGE part of the equation. As a rider I top 300lbs and a decent launch is not an easy thing to accomplish. As Brent stated, more cc is the easiest way. The extra torque goes a long way in getting you to that wheelie poppin launch we all love. However on a 70cc, with 190/130 porting and a pipe the torque is just not there until the RPM'S are elevated. I was using a HOCA variator (I believe the HOCA was a multivar copy) and pretty light weights in conjunction with a stock or slightly stiffer than stock contra spring, and a stock pulley. The clutch was a lightened stock clutch with heavy springs. This combination allowed the motor to rev up and get on the pipe, then the clutch should slip in late to get the scoot launched. I should mention a setup like this was not much fun in stop and go traffic. You make a lot of noise just to get moving every time. Here are some of the other things I watched closely to get the CVT set up to my satisfaction. How the belt rides in the front variator at rest: I like to be able to pull the belt around by hand and have it slip through the variator but also grab, about 50%. To loose and you are wasting variator travel, too tight and you lose some essential low gear IMO. Variator weights: As little as a couple grams change can make a big difference in CVT operation. Multiple weight changes required to find the sweet spot. Lots of tuning weights required. Variator fixed half: mods to the face angle in the boss area can help, sometimes. Clutch setup: The clutch has to be able to get the power to the wheel, it has to slip in, and eventually lock up as best it can. A stock clutch is not ideal but can be modded to work. Now days I prefer to use an adjustable clutch such as the Dr Pulley HIT, or the Stage 6 that is adjustable. Due to my weight I am very hard on clutches, so I am always looking for something better in a clutch. Remember these are MY observations as a setup for a HEAVY rider. I would love to be 100lbs lighter and see what works for me.   |
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Post by ThomasTPFL on Jan 20, 2019 18:13:41 GMT -5
What exactly are you looking for information wise? Mostly curiosity's sake. I've been searching for builds online and can't find much since I don't speak any European languages so I can't effectively search their forums. I see these stripped down "50"cc bikes that are smoking the back tire and launching super hard and got interested in what kind of clutch and other components they run with. I mean, I wouldn't run the same setup on my road Mustang as I would on my quarter mile Mustang... Hell, I also wanna know how road race twist n gos get their transmissions to "downshift" harder. |
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Post by benji on Jan 20, 2019 21:15:26 GMT -5
Downshift is controlled by the torque spring and the angle of the slots in the torque driver.
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Post by lilpinny on Jan 20, 2019 22:55:57 GMT -5
N2O helps. It's gonna twist your frame and it's only good when you are wide open. Once you break free and all up in your RPMs, hit the button.
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Post by ThomasTPFL on Jan 21, 2019 0:37:09 GMT -5
Downshift is controlled by the torque spring and the angle of the slots in the torque driver. Yeah, I’m still not confident on torque spring changes. I need a few more in my box, and ones to fit all my rear pulleys. I’ve seen a few driven pulleys on the market with multiple angled slots to choose from, I’ve thought about getting one of those for tinkering purposes. |
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. Being nimble beats top speed.
