do you no how fast one of these gose

[FLICK]

............

 

[minidirt]

it will just take a little longer to get to it's max speed.

hell we were thinking the same thing for once!

and symposium give up you are looking like a fool, i'll try and think of all this friction you are talking of. from the added 100kg, hmmm, well maybe a fractrion of a newton of more fraction in the wheel bearings, maybe a little more friction in the interaction between the tyres and dirt, these two things will not be slowing you down, the only thing that would make a difference would be a larger riders increased frontal surface area, and the greater air friction cause, and as you know air friction would increase at a square of the speed, but to 70kph probably not an issue. maybe the heavier rider compresses the tyre another mm, decreasing effective circumfrence, probably not an issue, so all my points are wrong and stupid.

 

[mini_motox]

but is a crf80f faster

 

[mini_motox]

sorry my computer was playin up

 

[mad man]

but is a crf80f faster

hey man it doesnt really matter what is faster?? i would say they are about the same and orion mite be a little faster ok? good luck man but i would buy a beta quality bike from mso or something, but your choice man so goodluck and happy riding..

 

[FLICK]

............

 

[mad man]

omg, guys this kid is like 12? and yes i think it would be but probably the same speed, end of topic????

 

[eichkay]

I haven't been able to find the primary drive ratio or gear ratios for the Ducar so I just removed spark plug and magneto cover, put it in 4th gear and counted the crank revs per front sprocket rev, which was 3.9:1 (+/- 0.05) ..

so:
primary drive x 4th gear = 3.9:1
14 front, 37 rear sprocket = 2.64286:1
12" rear wheel circ. = 1465mm

1000rpm (in 4th) = 97rpm of the rear wheel = 0.1421Kpm = 8.5263kmh

so:
in 4th with 14/37 sprockets
1000rpm = 8.5263 km/h
2000rpm = 17.05 km/h
3000rpm = 25.6 km/h
4000rpm = 34.1 km/h
5000rpm = 42.6 km/h
6000rpm = 51.2 km/h
7000rpm = 59.7 km/h
8000rpm = 68.2 km/h
9000rpm = 76.7 km/h
10000rpm = 85.3 km/h

Very interesting ... sounds about right from what ive seen with the GPS, well done.. stock CDI's tend to have a rev limiter at 8800rpm from what ive seen..

I've got a 10" wheel and 17-37 gearing and the max ive got out of my bike with a TB CDI was 90km/h so 76km/h with a 12" and 14-37 whould be about right IMO.

 

[FLICK]

............

 

[minidirt]

Hmm, if it's a brushed motor wouldnt the (electircl) Magnetic field comes from the armatur itself and then act against the magnetic feild around the armature... blah blah argue spam.

 

[FLICK]

............

 

[minidirt]

no arguments here with that, just wondering how fast a standard 125, (jialing, ducar, lifan, whatever they are all close stock) will go, in terms of where air friction limits you before gearing does.

 

[Mack]

Even an electric motor is subject to the same principle if used for speed. It may suffer losses which will affect the rate at which it accelerates but at the end of the day it is the max power output which governs how fast it will propel any vehicle. You are correct flick in that engine revolution is a constant, comparable to the achieved vehicle speed. But your calculation is only valid within the horsepower range of any given machine. Symposium is completely correct in trying to factor the opposing forces to max speed in this thread, which is what we have been asked and what we are talking about. I doubt neither bike will run to full revs in top gear. The bike with the lesser hp will simply meet its limit at a lesser speed. So your chart is useless in calculating the potential top speed of anything unless it can rev to its limit in top gear. But then you would still have power left, so could go faster. Change gearing and round we go again. Now to calculate the speed potential of any machine you must use the formula I quoted. Guys here are asking about max speeds and achieving higher speeds. So we are dealing with the limits of power not gearing. In other words your last two lines on your chart may be negligable for a 8 hp motor, or you could add two more, you just don't know. So you can't answer the question which bike is faster.

 

[FLICK]

So your chart is useless in calculating the potential top speed of anything

Easy fixed... I'll just delete out all the useless info.....

 

[Mack]

Easy fixed... I'll just delete out all the useless info.....

Sorry flick, didn't mean to come across that way. Just thought Symposium was thinking along the right lines to answer the top speed question. Good debate.

 

[holland1]

they go really good i have one they go good theyll beat a crf80 for sure