Zoomer-X

[freedomnow]

The shop said the stock tire/tyre is 110 and max they can put is 130 without needing the air-filter/exhaust on either side to be modded or upgraded.

Think I will just get them to upgrade the variator at the expense of KPL....you 2 guys talking over my head with technical details in the 2-wheeler diesel-head thread...

Edited January 22, 2015 by freedomnow

[dave_boo]

Dave,

Due to friction in transmission, torque measured at the engine output shaft will be greater than torque measured at the rear wheel.

So much for your 'torque multiplier' theory.

Torque and power both increase with rpm until in or near red line.

Changing the variator causes engine to run at higher rpm hence more power and acceleration.

If y'all want to call this 'more torque', fine, but,

if you bias a variator for max torque rpm rather than max HP rpm, it will accelerate a bit more slowly.

Power is power.

But people like to say torque.

They may not be able to define it or spell it, but....

a simple-minded, inaccurate model is more palatable than an unfamiliar, rigorous analysis.

Cognitive dissonance.

T=r x F

Note that "x" is cross product, but can, in "a simple-minded, inaccurate model", be approximated by the multiplication sign.

Of import is the "r"; that's the displacement vector. Torque is not a simple F=ma formula! I'm not terribly hip on how CVT work. Meaning I've never sat down and theorised as to all the complexities, but the general principle is simple enough. At lower speeds the weights are in a position that corresponds with lower gears on a real transmission. As vehicle speed increases the weights move into a position that changes the diameter of the pulley so it corresponds to higher gears. The mass of the weights can be varied to control the speed at which these changes occur.

So at slower vehicle speeds the pulley which contains the weights retains a size, in relation to the other pulley, that provides a certain ratio. Without knowing the exact number, let's assume that this is 3:1 where the pulley with the weights turns 3 revolutions for every single revolution of the other pulley. As the pulley's diameter is changed due to the shifting weights, it get's larger and let's assume it reaches 1:1 where the size of both pulleys is the same and every revolution the pulley with the weights makes causes the other pulley to rotate once also. This is why high rpms at lower speeds makes it easy to take off but not go very quickly, while higher speeds means that increases in the engine RPM does not correspond to changes in velocity at the same rate as when at lower vehicle speeds.

So far, we agree?

So why did I post all that? Because, going back to my first line, Torque = displacement vector and cross vector with force. Displacement vector is also measured in rotational speed. Thus if you are at the 3:1 ratio, the driving pulley is going 3x the speed of the driven pulley. If one can not make the logical conclusion that going 3 times the speed of the 1:1 results in higher torque being transmitted...I can't help.

And driveline losses aside; there's a reason that a dyno is calibrated and ran in 'X' gear; otherwise the lower gears would return results that made no sense.

Your claim that torque increases (with the implication it always does) throughout the RPM range is disproven on pretty much every dyno from the lowly Ninja 250 (which starts at ~13 @ 5,000 RPM and peaks at 13.4 lb_*ft @9,900 RPM or about 3/4 its max RPM-but I don't really consider a climb of 0.4 ft_*lbs to really prove anything) on up to the Rocket III which has a peak torque of 136 lb_*ft @ 3200 RPM...just a bit over 1/2 it's max RPM.

You're quite correct about changing the weights allowing higher engine RPMs. However, it's not the higher RPMs themselves that provide more torque (if you believe the manufacturers don't design the engines and transmissions to compliment each other so that the transmissions attempt to keep the engines in their best range for torque...well patent the "more RPM for more torque in a CVT design" and sell it to the manufacturers!) but rather using the ratio for a longer period of time. Coming from the factory a CVT transmission 'short shifts'; as you well know running all the way through a gear is much preferable to changing up even if it is less efficient.

[freedomnow]

Michelin City Grip.....amazing....like tracking on rails.Got the widest rear possible without needing parts mods around the wheel, which was 130

I also recommend anyone buy the 800 or so Baht variator tuning kit. Given my ZX a new lease of life....like a different bike with those 2 mods.

10/10 upgrade...Dunlop tires were so bad now... I can feel such a difference in cornering.

Got an after-market YSS shock as well, my last gas/oil YSS had broken with a leaking seal....never picked up on that.

my local repair shop told me not to get the external chamber gas/oil YSS shock but the half-price 1000 Baht one which he swears by.

Wish I got the variator mod Day 1, feels closer to a Click i now for kick.

Edited January 23, 2015 by freedomnow

[papa al]

Dave,

Torque.

Torque = HP x 5252 ÷ RPM

So yes torque goes down as an inverse factor of RPM, up proportional of horse power.

So what?

If I want to have a ride that takes off like a scalded cat and goes really fast on top I'll choose a ride with power.

Horse-power derived from high rpm, or > displacement, +1 charging, high compression, nitro, whatever.

If I want low down pulling power, then I want an engine that develops good power at low rpm.

Formula 1 engines turn really fast for power.

Forget torque. Screw torque.

Power to the people, right on!

[freedomnow]