OK, I'm not a dyno xpert.Does it measure top speed mathematically? Does it compensate for wind resistance,rider weight,or riding surface? Does a TRX250R really go 72? I hope so!

 

The shop I go to has a Dynojet chassis dynamometer it is an inertia type chassis dynamometer.
What it means is that it calculates horsepower and torque based on how quickly the rollers move in a given inertia, in this case, a set of rollers of a given mass and dimension is accelerated.
The length of time it takes to accelerate from one rpm level to the next is the sweep time and the rate that you accelerate from one rpm to the next is the sweep speed or sweep rate. Cuz it takes more power to accelerate the mass faster, you will see lower horsepower figures when an atv is tested in a lower gear. This is cuz at higher speeds and higher gears, it takes longer to accelerate from one rpm level to another for example, 2000 rpm to 6000 rpm.
This stands until the gains in horsepower from increased sweep time are offset by the increased frictional losses of the gearbox, gearing and tires.
As speeds increase, the frictional losses in the gearbox, gearing and tires increase. The higher the horsepower of the atv, the faster it will accelerate the roller and the higher the speed will need to get the sweep time long enough to give an accurate reading. Cuz the Dynojet chassis dynamometer is an inertia type chassis dynamometer it does not allow you to perform fixed rpm or step type horsepower tests you can not hold the atv at a given rpm or speed and check the horsepower level.
The inertia type dynamometers gives you a very accurate measurement of what the atv see's in "real world situations". An inertia type dynamometer will show the effects of reduced weight such as lightweight flywheels, gearing and wheels while a steady state test does not show these improvements.
And yes the TRX250R can top out at 72mph!!!
That answer your question.

2000 SCRAMBLER 400 2X4

SCRAMDADDY400

 

I was riding in ice the other day and my friend was on his snowmobile beside me and he said i was doin 60 on my 250X but i was spinning the whole way. I'm not tryin to start an argument but thats just what he said and yes his track is studded so there;s no way he could have been spinning.

 

My Raptor was doing 98 MPH down the road the other day, would have gone faster except the truck is was in the bed of is governed at 98.

Hey Scramdaddy, your numbers have the DS topping out higher than the raptor, i thought i heard the raptor was slightly faster, even from people that own both?

 

660R01 unless they have accurate speedo's on their machines its impossible to determine the top speeds, the raptor has quicker take off making it seem faster.
The dyno that ran both machines has a highly accurate digital speedo and tach.
The DS was able to reach a higher top speed but it took longer to get there, the DS was also able to reach a higher rpm than the raptor.
The raptor has a faster take off reading 0 to 30 at 3.02 sec. vs the DS' 4.28 sec.

I dont want to get flamed on this, I stated readings off from an accurate dyno and besides it was only 1 mph, who cares.

2000 SCRAMBLER 400 2X4

SCRAMDADDY400

 

Hey ScramDaddy

Do you have any numbers for a Scrambler 400 4x4 (or 2x4) with pipe, Clutch Kit, or other mods?

It would be interesting to know

Thanks KD

 

A mojave can do 50+withut going downhill or gust of wind my friends old 88' Mojave still clocks in at 52mph and its pretty beatup.

 

Great info Scramdaddy! You seemed to have a very acurate source with some very nice equiptment. Don't mind those that are nitpickin' for 1 mph!!

Kevin, I am getting my Scram400 4x4 dynoed in April when I get it ported. I will let you know if you want. (before and after)It would be cool if Scramdaddy could get us the figures first though.

 

Xplor:

Cool. Let me know (if Scramdaddy can not find out). What does it cost to get one Dyno'd? Where does one find a Dyno?

PS I got mine back running again after the tree meeting.

KD