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who here has topped out there 250 kawa ? if so.. how fast did YOU go... not what the net says... 105 mph.. supposidly... so.. how fast did u go :shock: :D ?
 

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250 TOP

Kawasaki keeps changing the darn gear ratios, so...it depends upon the gearing on your bike and any mods that you have and primarily your aerodynamic ability. The guy who was 5'10" the other day couldn't get mileage out of his new one...because he is setting upright most of the time...possible solutions taller windscreen, changing gear ratios, or even getting a seat from the salvage yard and reshaping it so that you are set further back in the saddle, giving you more length to drop your body...top end depends upon lots of things...105MPH is about what you will find for a STOCK machine without any mods after break in...give or take of course for gearing, difference in tires, and all of the above. You want to get real serious about top end go through and set up a seat for your exact height so that you are truely tucked in at high speeds, then exhaust, then some wicked carb work, better plugs, K&N Airpods, then you will be able to start working on the gearing for your bike...There is no doubt in my mind and experience that you couldn't hit 140MPH IF you want to set it up right for topend. Personally, I'd rather put soft tires on it, lose some topend so that I have a killer FIGHTER machine...at 51 I'm not worried about my clean record being smudged...I'm ready to drop the rear sprocket to make some killer rocket power and BLOW away the larger bikes in the city. There is NO way that I will have the topend when I do this, but gearing down lets you rip. Have you ever ridden a bike that would pull the front wheel shifting into 5th if you weren't being careful? Should they do bike runs in the KC area of Kansas, I'll let you know what a 250 can do.
 

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I'm changing my sprockets to give me more top end power (but really to lower my highway RPM's). In the process I did some calculations for top speed. These calculations consider running at 14,000RPM redline in 6th gear on a stock 2001 bike. Other years may have different transmission gearing. I know the early Ninja 250's had a different rear sprocket. These calculations do not consider aerodynamics, friction, weight, horsepower, or any of the very real factors that affect top speed. I'm only looking at "if you're doing 14,000 RPM's in 6th gear, how fast are you going?" Anyway, here's what I came up with:

The transmission has a primary reduction of 71 teeth to 23 teeth. Sixth gear has a ratio 25 teeth to 28 teeth. The front sprocket has 14 teeth. The rear sprocket has 45 teeth. So to determine the RPM's of the rear wheel, just multiply 14,000RPM's * 23/71 *28/25 * 14/45. That gives you 1,580RPM's. This part of the calculation is quite precise.

Now you just need to know the circumference of the wheel to determine speed. I calculated the theoretical circumference, not taking into account a) that tire radius is less at the bottom than anywhere else, b) that the radius increases at highway speed, c) that radius gets smaller with tire wear, or d) that radius increases with tire pressure (which also increases with temperature). I also assumed that the radius is exactly the rim radius plus the tire radius (which it is not). Anyway, here's what I got for radius:

The rim is 16 inches, so the radius of the rim is 8 inches. The tire is a 130/80/16, so its width is 130mm, and its height is 130*80/100mm, which is 104mm or 4.094 inches. So the combined radius of the rim and tire is 12.094 inches. The circumference is 2*pi*r, which is 75.99 inches.

So 1,580 rotations/minute * 75.99 inches/rotation = 120,087 inches per minute. Multiply that by 60minutes/hour to get inches per hour. Divide that by 12 inches/foot to get feet per hour. Divide that by 5,280 feet/mile to get miles per hour.

And the answer is . . . (drum roll, please) . . . 114mph.

Naturally, that is assuming that you have the aerodynamics, horsepower, straight safe road, etc. to actually make it to 14,000 in sixth gear. So what this calculation really means is not that you can make it to 114mph, but rather that you can't go over 114mph without changing the sprockets or rear tire size.

And just for fun, if you change your front sprocket to 17 teeth, and your rear sprocket to 33 teeth, and you put on a 140/90/16 tire, then you can't go faster than 202mph, which we all knew already.

Isn't math fun?
Curt
 

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200+MPH

Curt, I too have a likeness for math...it gets better...when someone sees what you just put on here and looks at it, then starts adding in technical Physics. Kinetic Energy, stored energy, potential energy, Moment of Inertia, inelastic collisions, drag, force, coheasion, rolling resistance, inclines, altitiude (gravity), barometric pressure, relative humidity...aerodynamics, friction... I'm 51 and into commuter rocket science. I have a desire for the open road speed traps and top speed, but for me right now, I live in an area of old US Highways that are all but forgotten because of hte newer interstates that have replaced them. I-35, I-435, I-470, I-70, some old/old US Highways are now parkways, but some of them are just awesome twisty turns that drop climb with the natural terrain. Then too, I'm blessed to have the old Santa Fe Trail, California/Oregon Trail, and all passing right through here with the old Army roads from Ft. Leavenworth to Ft. Scott...and such. The old Kansas City Road, Edgeton-Olchetree road...roads that were used over a hundred years ago that are still used but are now named things like 199th street. I'd like to see a full on real tuck in race fairing for the 250R. Kawasaki an dSuzuki share ideas and such so I see a full fairing coming to te Kawasaki 500R real soon...but I really want to see something aerodynamic like a ducati fairing on a 250R. getting a second seat and changing it with small pads to get th profile perfect is my first project after I get my bike out of the Salvage yard. Using a bare seat, removing the cover and foam and then placing myself in the sweet spot and building up what I need for a saddle to stay tucked in and set in the slipstream provided by the windscreen and fairing...footpegs, shifter and brake can have their position altered easy enough. Finding the right tires is becoming an obsession with me. Metzler is pushing their ME 330/550 pair, dunlop the 501's, but I'm looking for something...very sticky for town to town thrashing. When I get ready to do my cross country riding then it's just a matter of changing the rear wheel tire, sprocket all at the same time and the chain as well for a touring or sport touring tire. LOVED THE MATH!!!
 

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from an earlier post:
Viper_05 said:
yea im 16 too.. just picked up my 2002 EX250... its a pretty pimp bike... i plan on killing myself on it :shock:
While we're on the subject of math (and therefore physics), remember that the formula for kinetic energy is KE=(1/2)mv^2. That's right, the velocity is squared. So if you're trying to top out that bike and you have a collision while doing 100mph you'll have four times the brain damage of a collision at 50mph. If you factor in that your helmet absorbs the first part of the impact, then the 100mph collision may give you more like 9 times the brain damage of a 50mph collision. It's not the collision that will kill you. It's afterwards when your brain starts to swell and you're skull won't let it. So you'll be able to get up, dust off, and pick up your bike before you black out and fall over. Then you just wait for the increased brain pressure to kick in. Hope you said your prayers.

And if you don't wear a helmet, you'll be four times as dead . . . um . . . okay, the math doesn't apply there.

This is all humorous and hypothetical, but collisions are very, very real. And on two wheels, a tiny mishap or misjudgement can put your keester on the asphalt or under a truck. Motorcycling is fun in itself. It doesn't have to be dangerous to be fun. I'm getting off the soapbox now.

Hey, ZX-2R, I just saw in your profile that you're into Studebakers. Two days ago I saw something I've never seen before -- a Studebaker pickup. It was not restored, just parked in the driveway at a house right here in Minnesota. It was really something to see.
Curt
 

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STUDEBAKER

IF www.studebakermotorcomapny.com gets rolling (midland, tx) then I'll be down there for a spell...the forst bikes will hit the road followed by trucks and then cars, then most likely a hybrid. My 1951 Commander State will get a new SMC EFI with 4/5speed automatic and we'll follow its every rpm with a computer/computers, even as I drive it locally and back home for weekends...I hope to ride the SMC motorcycles and give some feedback to them on things...I've been assisting the CEO for the past two years on ideas although I'm not an engineer. I'm just a plain t-shirt guy that can wear a white shirt if need be, but prefer to eat home cooked food and drink a squeek of beer or wine, but prefer cows milk, maybe sweet iced tea. I've had some ideas that I popped out two years ago just come out this year, and some that so far no one has used...maybe SMC will use them first and I'll get to do some work and get paid for doing some thinking. I'm real excited about the bikes and trucks, even the cars, and i'm pushing the CEO and Engineer for a world class GP250cc bike that will rock the market. You already know most of my ideas on the 250 but I have a few tricks up my sleeve that even the DOT won't have problems with, and will make SMC stand out like a knight in shining armor. I'm excited and I just want to get the assembly line rolling on the big bike so that we can get onto other things...
 

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250 speed demons

my zxr250 (u guys get zx2r) with the derestricitor plugged in will do 130mph wiv me in full crouchdown nailing it for a few miles in me mates tailwind, although only 125 without his tailwind.
my kr1s which you guys dont seem to get in the states will do 135mph plus. but she's not stock.heehee
 

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250's

Actually the only 250's that we have are the EX 250, which has the decals that say Ninja and it is most commonly refered toas the Ninja 250R. The other 250's that are available is KLR250 Dual-Sport, and the KX250 dirt bike... I wanted some identifiable Screen Name so I chose the controversial ZX-2R. I'd like to see an old E Model GPz250, even own one some day. A true racing bike ZX-2R would be cool but we have a the Federal imposed Speed Limit of 75MPH...which is slow enough for the 250's to ride on all day long. Geting the most out of the bike for any track or for any cocky city riding can be done by simple modifications...including some inexpensive wheel sprocket, countershaft and chain changes. It cuts the fuel economy real fast, but it makes the bike so much more fun to ride on the back roads and in the city.
 

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If you guys continue like that, tomorow or so Ninja 250 will be the fastest bike in the world. :D A bike with 33ks can do about 105mph. Any speed over 110 is ohoho, but downhill or with back wind (a good one). :wink:
 

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Street bike

For my Ninja 250R a SPORT-Bike for sport and that is just it. If I wanted an Interstate bike or a cross country bike or a dual sport then they would all be different bikes. A 250 set up from the factory gets a guesstimate of 65miles per gallon...what about a 600R, something like 35Miles per gallon? So the way that I look at things and the way that the rest of the crowd looks at things...who cares...about the gas mileage...it's al about having fun. I think that when you look at dolars spent to have the same amount of fun (my fun) then it is much cheaper in the long run. Change up the gearing, change out the fairing (the stock plastic is overpriced and to thin), make it breath in and out, forced air, shave the seat so that it fits only your own torso length (no one else should be riding my bike anyway) readjust all the controls so that they are "perfect", find the proper heat-range plug for my style of riding, tire pressures set for appropriate, not average riding, set up the suspension so that it is just perfect for ME...not for the average person...I'm not average, nobody is "Average." So there is a difference in bikes and a difference in what and how bikes are used. There is a difference in cost involved as well. Sure you could ride any bike, basically they're all rideable...a sport bike, personally to me is just that, a sport bike. Cornering, figure 8's, slallom, maneuvarable, stop...go...and if it gets broken it's not an $8,000.00 bike with lots of add ons racking up the total upwards of $10,000.00 and insurance...all the major costs involved. The Average guy very seldom uses a centerstand...why not get rid of dead weight?...We now have technology to turn engines upwards of 19,000RPM... with the dry film lubricants, thermal barrier applications, using titanium, aluminum, magnesium, lighter wheels and tires, lower profiles for less Moment of Inertia...all these combined...we have some awesome changes coming to motorcycles. So don't be surprized when your vintage bike is blown away by a newer model...and never underestimate a smaller machine. I know that I have a tendency to soapbox, but I get irritated with the term AVERAGE, and OUTRAGED when someone/anyone has something to say about a quarter-Liter bike. The Bat-cycle was a 250cc bike...okay that's not average??? Racing is still using a quarter-liter (yes a 250cc) motor. I guess that in the end IF you really want to be exact...the Ninja 250R, it isn't really a quarter-liter bike...it's less than that, and I have to admit that in reality it IS only a 248cc motorcycle.
 

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USELESS BIKE

You want a USELESS BIKE how about the twin-turbo "busa"? 250 miles per hour+! I'm impressed? Hardly. A perfect bike for the streets and highways of Los Angeles county...NOT. A perfect bike for Nevada Interstate driving...till you got stopped! I wonder what insurance would run on one...not really. Everyone has their own identity. No one is average. I feel better now!
 

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250 speed demons

we have a 70mph speed limit on our fastest roads overhere, it's upto the rider whether they stick to it or not. i believe the ex250 that zx2r is on about is what we know as the gpz250r, which is another grey imported bike from japan. this is a 8 valve twin four stroke that was also used in the gpx250 and the zzr250. the zxr250 i have is a four stroke 16v lump weighing next to nothing. the kr1s is a two stroke twin, with loads of race kit bits sourced from guys in the supersport series racing we have over here, where two stroke 250's often beat the four stoke 400's when racing. the kr1s quite often runs about 20mpg where as my zxr does 50mpg. the same as my zzr600. if you really wanted a cheap 250, why not investigate a personal import from japan, where you can get a excellent deal for less than $2000. if you need more info on this route, just let me know. although i dont know whether your motor laws would let you do this cos from what i understand you seem to have different laws for different states, but could be worth a look at. ride safe guys....
 

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250's

WOW!!! I wish that it would be easier...but our Government has really cracked down on vehicles, especially the 2 strokes. Even Chainsaws for cutting trees and now string trimmers have catylitic converters on them. The EX250 (Ninja 250R), is the only 250 left, except maybe Honda which has a cruiser bike. I don't know how a person would go about getting around the Government here to own one. Laws vary from State to State as well. California is the worst. Here in Kansas we are considered Farm country and if you live on or near a farm, catalytic converters on cars/trucks may be removed to prevent the extremely hot canisters from setting fields on fire. So I have my field mowed and baled and always leave bales stacked around, and use the old ones for mulch or covering the wifes flowers in the winter. Maybe I could ask Uncle Bob, our Canadian moderator, on the forum. Kansas has no testing stations or annual inspections on vehicles like most states have. Thank you for the information!!!
 

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Well, the most I've got it up to so far is 165 Km/h, it tops at 200Km/h, or so it says! This thing is scary as **** when it gets going, seeing as how it has no aerodynamics whatsoever.

Good times though.
 

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Re: USELESS BIKE

ZX-2R said:
You want a USELESS BIKE how about the twin-turbo "busa"? 250 miles per hour+! I'm impressed? Hardly. A perfect bike for the streets and highways of Los Angeles county...NOT. A perfect bike for Nevada Interstate driving...till you got stopped! I wonder what insurance would run on one...not really. Everyone has their own identity. No one is average. I feel better now!
It's good to vent! :) I wish I had the money to buy a new Busa and pay the insurance. I wouldn't buy the bike, but I would like to have the money. I doubt going 250 mph on a Busa would be comfortable or even much fun - more like holding on for dear life and hoping you don't hit a small pebble.... But the regular 'busa is a very cool bike if you're into that sort of thing.

BTW: My 250's slower than your 250! :eek:
 

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SLOWER?

SLOWER? IF you had the same bike exactly an dyou both took the same bike aroune the track or even through a 1/4 mile the results may be exactly the same that one of you is slower...but, if yo were to take a camera and see your riding stance, I think that you would see a big difference as well. Keeping the aerodynamic flow clean is the answer. If you hang arms out, legs out that can be fixed easy enough, if yo are taller then change windscreens, or set further back on the seat to lower your body into the slipstream...even shaving the seat, what ever it takes to be comfortable and get a great ride...then again you could change gearing...
 
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