is it possible?

[vic1616]

is it possible for my 125cc china pitbike's max speed to be only 50kmph because it certainly doesnt seem very fast when im going full on the throttle in fourth gear... or is a 125cc a too powerful engine to be only outputting 50kmph

 

[motorman]

is it possible for my 125cc china pitbike's max speed to be only 50kmph because it certainly doesnt seem very fast when im going full on the throttle in fourth gear...

It's definately possible. All to do with your gearing. Must have a really tall rear sprocket.

Count the teeth on the front and rear spocket and post it up.

 

[vic1616]

It's definately possible. All to do with your gearing. Must have a really tall rear sprocket.

Count the teeth on the front and rear spocket and post it up.

will do tomorrow and see if its normal., how many teeth is considered to be "normal" on the front and rear sprocket?

 

[motorman]

will do tomorrow and see if its normal., how many teeth is considered to be "normal" on the front and rear sprocket?

There is no "normal" amount on any bike really. Could be anything. If you brought it 2nd hand could have been changed as well.

Just count the teeth and go from there.

 

[vic1616]

There is no "normal" amount on any bike really. Could be anything. If you brought it 2nd hand could have been changed as well.

Just count the teeth and go from there.

Ok, ill post the front sprockets amount of teeth and rear sprockets amount of teeth tomorow and you can let me know what you think

 

[vic1616]

and no i didnt buy it second hand, i purchased it straight from the crate at the pitbike dealer

 

[motorman]

and no i didnt buy it second hand, i purchased it straight from the crate at the pitbike dealer

What bike is it?

You should be able to find it out on there website?

 

[vic1616]

What bike is it?

You should be able to find it out on there website?

i cant find it anywear on the internet but heres a pic of it

its pretty much a no name bike lol this is the code from the engine is all i can really get from it although i know it is a 125cc

code:TZH157FMI

 

[sam93]

You can get your bike going a lot faster than 50kmh. But like Motorman said it is all with the gearing so as soon as you count them you can sort it out.

Their is nothing right or wrong about short or long gearing it is all personal prefference.
I like my gearing long just so that I do not have to be revving hard all of the time, My old Ducar 125 got to 109kmh and could have got higher but didnt want to on a bumpy dirt road with pot holes. I was running 17T front, and 37T rear with 14/12" wheels.

But in saying that for riding a track I would change my gearing to something like 15T/39T to make it have harder acceleration and lower top speed because you dont need that top end speed on a track (usually).

The rule to gearing is:
The larger the front sprocket the higher the top speed is.
The smaller the rear sprocket is the higher the top speed is.

But keep in mind with the higher top speed, you will be loosing acceleration and torque to a certain degree and you need to find what you like the most. So the best thing to do is once you know your gearing buy a few and change them untill you find a good comprimise....

Sam93.

 

[MiniFighter]

Id be suprised if it is actually capable of doing 50.

 

[motorman]

Good post Sam.

Oh and a general rule of thumb:

3 teeth on the rear is equal to 1 on the front

 

[MiniFighter]

Good post Sam.

Oh and a general rule of thumb:

3 teeth on the rear is equal to 1 on the front

I think you will find its two, not three

 

[Barnesd09]

If your on 12" rear wheel, 50km/h at 9000rpm the gearing would have to be 13/55
Generally you will find that most bikes come with 15/38 which is good for about 85km/h at 9000rpm

open View attachment 5173 file and plug all the specs in and you will work out what gearing does what.

If your engine isn't in there let me know and I'll update it with the specs.

 

[motorman]

I think you will find its two, not three

Nope it's definatley 3.

2 wouldn't even be close.

You want me to pull the calculator out?

 

[MiniFighter]

Nope it's definatley 3.

2 wouldn't even be close.

You want me to pull the calculator out?

I dare ya too...

 

[Carlts]

Ill give unnecessary reps to the winner, hows that for competition then!

 

[The_GDFP]

Sounds geared too tall to pull 4th.

Honda50.com Gear Ratio - Speed Calculator

http://www.jtsprockets.com/fileadmin/files/jtgearratio.pdf

 

[The_GDFP]

I wanna be in the contest! I pick 1

 

[The_GDFP]

And 7

 

[MiniFighter]

I wanna be in the contest! I pick 1

hahah looks like a front on the rear.

I was always told, dropping one in the front, is similar to going 2 up on the rear. And vice versa.