Top Speed?

[peter330]

Hey guys

Was wondering what you all have experience as your top speed swith a stock Ninja 250. Not downhill, no back wind, just a straight modest top speed. I ask Cuz the most my Ninja goes is 93 mph and I think it should be more. I've heard anywhere from 95mph to 105mph. I have done the shim DIY and snorkel removal, 2 washers on each.

[miks]

Those "95-105mph" figures are indicated, but as most people will tell you the speedo is off by roughly ~8-10%.

[alex.s]

when my ninja was stock, it's jetting was rancid. couldn't get her above 85ish on flat ground according to gps. did a jet kit and now it tops out at the rev limiter fairly easily... not sure what speed this is since i stopped carrying a gps with me since it's been jetted, but the speedo reads about 110... should be about 95-100.

side note- it's a bad idea to run it that high on public roads.

[Snake]

My "indicated" top speed has been 110 mph. My actual is probably 105. Keep in mind that it took me at least 2 miles to finaly get to that speed.

[Racer x]

the speedo is off by 10 %.So at 110 you should be indicating about 100 and at 55 you should indicate about 50.

[Samer]

It does seem somewhat slow because I've hit 100 mph GPS on mine and I have not modified a thing on mine. South Florida is pretty much all flat so it is an even playing field.

Do you tuck in all the way? It almost goes without saying but I'm just wondering what it could be. You should be pretty much right on the red-line in 6th gear, and the speedometer should read somewhere slightly above 100 mph.

[Racer x]

Aerodynamics are everything when you only have 30 hp to fight the wind with.
Be careful getting into a tuck on the street. First of all you r view of the road ahead is not good.And even if you are only going 55 .The cops will see you and figure you are on a sport bike all tucked down .You must be speeding.

[ninja250]

Originally Posted by Racer x

the speedo is off by 10 %.So at 110 you should be indicating about 100 and at 55 you should indicate about 50.

This seems to be correct in my case. The amount the speedo is off is proportionate to how fast you are going. I.e.. the faster you go, the more the speedo is off. I indicate 101 when I'm going 90ish. About 50mph when indicating 55

[ztrack157]

fastest guy on here is Eric and he is at 112 with mods. I think 105 confirmed is max with the rider weight at 120 pounds.

[Samer]

Originally Posted by ztrack157

fastest guy on here is Eric and he is at 112 with mods. I think 105 confirmed is max with the rider weight at 120 pounds.

Not to turn this into a big discussion, but rider weight has nothing to do with top speed. Volume is another matter though

[Reswob]

100 indicated. I have yet to borrow a gps to check against the speedo.

[DEXSPEED]

by experience 102-104mph flat straight shot road

[ztrack157]

Originally Posted by Samer

Not to turn this into a big discussion, but rider weight has nothing to do with top speed. Volume is another matter though

it's ok I don't know anything about anything

[fujimumu]

Originally Posted by Samer

Not to turn this into a big discussion, but rider weight has nothing to do with top speed. Volume is another matter though

increasing the mass of an object will increase the friction created with the object it is contact with (tires to road), increased friction will reduce top speed as the engine must work harder to overcome the extra force.

try sliding a paper across a table; easy enough right? now try it again with a brick on top of it...

[Alex]

Originally Posted by fujimumu

increasing the mass of an object will increase the friction created with the object it is contact with (tires to road), increased friction will reduce top speed as the engine must work harder to overcome the extra force.

try sliding a paper across a table; easy enough right? now try it again with a brick on top of it...

Nope. The rolling friction differences due to rider weight are a gnat on the backside of an elephant.

As for the second example, if that piece of paper with a brick on it had a nice set of wheels on it and the same force pushing it along the table, it would reach the same terminal speed as a hollow brick of the same size.

[fujimumu]

I stand corrected

[Gfortunes]

my local speed limits max out at 70 mph so of course I have never even tried to go over that!

[sofo]

Originally Posted by Samer

Not to turn this into a big discussion, but rider weight has nothing to do with top speed. Volume is another matter though

We are talking about small displacement motorcycles, not ship hulls right?

I'm 210, buddy of mine is 140. If we share the same 250R, run the same launch, shift points, tuck and statistically-impossible weather and road conditions, the 140lb rider will be faster, guaranteed.

If you don't believe me, put a couple of 45lb barbell plates into a backpack and see how close you get to your own top speed. No really, try it.

[Racer x]

For what I do weight only matters because I" ONLY " Have one mile to accelerate. I am still gaining speed . For 1/4 mile weight is everything.

In theory weight dose not matter for top speed . But a 175 lb cyclist with 4 % body fat will go faster than a 175 ball of fat that watched to much TV. Because of the shape and aerodynamic drag from the larger sized rider.

For the record ..Drag racing is Weight VS HP. And top speed racing is Aerodynamic drag VS HP. Both in a straight line.

[Samer]

Originally Posted by Racer x

In theory weight dose not matter for top speed . But a 175 lb cyclist with 4 % body fat will go faster than a 175 ball of fat that watched to much TV. Because of the shape and aerodynamic drag from the larger sized rider.

..Drag racing is Weight VS HP. And top speed racing is Aerodynamic drag VS HP. Both in a straight line.

Can't argue with anything you said there. Nice summary.

For anyone surprised by the top speed thing, one way to think of it is that the heavier person with the exact same shape as the lighter person will just take longer to get to top speed because it takes more energy to get there. Weight absolutely affects acceleration (obviously) and unless you're going on a completely straight road at one speed the whole way, it impacts gas milage as well.

[Alex]

Originally Posted by Racer x

For the record ..Drag racing is Weight VS HP. And top speed racing is Aerodynamic drag VS HP. Both in a straight line.

[sharky nrk]

Originally Posted by Samer

Not to turn this into a big discussion, but rider weight has VERY LITTLE to do with top speed. Volume is another matter though

corrected. no arguement from me that aero is THE much much more important factor, but it an objects mass does have an effect on the velocity at which a rolling object stops accelerating due to opposing forces even if it is so minute.

[tjkamper]

Originally Posted by Racer x

Aerodynamics are everything when you only have 30 hp to fight the wind with.
Be careful getting into a tuck on the street. First of all you r view of the road ahead is not good.And even if you are only going 55 .The cops will see you and figure you are on a sport bike all tucked down .You must be speeding.

You can get an easy 5mph out of tucking. But yes the cops will be watching for you.

[Racer x]

Originally Posted by ztrack157

fastest guy on here is Eric and he is at 112 with mods. I think 105 confirmed is max with the rider weight at 120 pounds.

Fastest guy on here is Shiphteey .He went 112.7 I went 112.2. then and Team Mullholand has 117 and 119 with nitrous. I am just the biggest guy

[sombo]

Originally Posted by Racer x

Fastest guy on here is Shiphteey .He went 112.7 I went 112.2. then and Team Mullholand has 117 and 119 with nitrous. I am just the biggest guy

This reminds me of an argument I had with a guy here at work that had a pre-gen 250 that was totally stock. He claimed he got it to 120mph on a straight/flat stretch of one of the highways out here. He claims even a cop told him he was clocked at 120mph. He wouldn't listen to me about how it's impossible for a stock 250 to be doing 120mph on a flat road when even the manufacturer rates it at 110mph max. But hey, what do I know, I've only learned more about the 250 and have ridden longer then him. He's already moved up to a 600 bike now too.

[Racer x]

with a 10% error with the speedo . A first gen on flat ground with a tail wind could make a rider think they are going 120

[sombo]

Yah, I tried explaining that to him. Still wouldn't listen or believe me cause the cop told him he was doing 120mph, or so he claims it happened.

[ScorpionNinja]

108 MPH! GPS confirmed

[capt_bugaloo]

Hmm. There was a lengthy, positive review of the 250r in Motorcycle Consumer News a year or two ago where they took a stock 250r to a track and clocked a top speed of only like 96 mph or something. Maybe their test bike was a bit of a dog, but I can't see a stock bike doing much over 100 mph...

[Alex]

Just about all the published reviews have it between 92 and 95. Stock gearing/stock tires has the engine turning 12,300 RPM at 100 mph; and an unmodified bike isn't likely to have enough oomph left at that RPM to pull the bike at 100 mph; the power started tailing off well before then. Headwinds/tailwinds make a huge difference when we are so power-limited, so I have no doubt that some folks have seen a true 105 mph or even more on perfectly stock bikes in the right conditions, but duplicating it on flat ground with no wind is unlikely at best.

[Racer x]

all top speed comments be must stated under what circumstance.In other words. Was it top speed in one mile two miles 1/4 mile . Coming off the high banks at Daytona.
But your top speed without gear change and with favorable wind on flat ground in one mile is 97mph@ 12300 rpm. One tooth gear change will drop the RPM lots and raise speed a little