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Discussion Starter · #1 ·
Hi guys.This is my first post on this forum.It looks fresh and more ''next generation'':D
I am searching all the forums and sites for what i want.I wanna change the sprockets of my R 125
and i don't know which combination will be the best for my bike.It will be best to upgrade my front
sprocket to 15tooth and the back to 45tooth?Or 16tooth front and the back 45tooth?It has too many
combination but i don't know what to choose.Please help me out!!I have also visited this site
http://www.gearingcommander.com/
to get some ideas...
 

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What do you use the bike for mainly?
 

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Discussion Starter · #3 ·
I'm from Greece.We have too many open roads so i never stick to traffic...I want to get some top speed.Will the lack of acceleration been noticeable?
 

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Very. Gears will give the most change out of any mod you can do to this bike
 

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If you are running a stock bike, I really cannot stress how much you should KEEP your sprockets stock.
Yes, you can increase your potential top speed, but at the same time, you will find it even HARDER to GET to your top speed, let alone hold it.

When you ride now, do you find yourself sat on the limiter a LOT?
If so, then changing your sprockets will not make you go faster, only slower!

What I would suggest, is putting the 150 or even 180 cc kit on.
THEN you change the sprockets, and you will find yourself being able to easily hit 90mph.
 

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I have a full system exhaust and k&n filter installed on my bike
Yeah, unfortunately that makes little to no difference :p
I too have the same on mine..

I would SERIOUSLY reccomend sticking with the stock sprocket set up.

The only time I ever hit the limiter, is very occasionally down a steep hill.
The rest of the time, I am sat at around 75mph, TRYING to reach the top speed.
 

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That is 85mph!!!
Impressive.

You must be tiny, and weight absolutely nothing!!!
Either that, or you are fueling your bike with jagerbombs :p

Okay...

If you find yourself on the limiter a LOT, then try a slight increase.
You will have to see what sprockets are available to you.

I would say perhaps try a 15 tooth front sprocket. That would give you a top speed of roughly 148kmph.
Which is a little bit more, but shouldn't sacrifice too much acceleration.

If you still find yourself hitting the limiter too often, perhaps you could try then adding a different rear sprocket.
Although you will struggle to find anything else I reckon, you may have to have one custom made.
 

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Discussion Starter · #11 ·
I am 1,86 and i weight about 73 kilos:D In the site you suggest to an other member i saw that if you change the front in 16 teeth and rear 48 tooth(stock)as it is
you get a very good high speed.How much will this decrease my acceleration?
 

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16 front is almost equal to 100mph (159kmph) for the english amongst us :p

And I can almost certainly say, that a stock bike will NOT reach that speed.
I reckon that would SEVERELY impact your top speed, I would need someone more experienced to clarify this for me, but I really couldn't personally advise this.

I would say, that the 15t is the limit you will want to go really...
 

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To be fair, a 15t sprocket is only £13 on ebay (15 euros).
Try one, and if it still hits the limiter regularly, then go bigger?
 

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Discussion Starter · #14 ·
As i thought.I read to another post that they fitted a 16 front tooth and rear a 45tooth.Will this compination make out better performace?In Greece the sprockets costs about 3-5 euros.Very very cheap!!
 

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Now, I'm not sure about this.
I always see people talking about 15t front or 14t front, but I don't think that's the right move.
Looking through gearingcommander, I think a 1t change on the front is way too big a leap, nobody ever hits the limiter with a 15t.
How about changing the back only? Get some more top speed but not this massive leap
 

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Changing the back sprocket you have to cut the chain.Correct me if i am wrong
Not sure, I just know that the front sprocket is all I can find on the internet.

a 1 tooth change on the front = roughly 5mph Chip, that isn't a MASSIVE difference. Enough to be noticeable sure, but I think that is the point :p
 

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Finally, the expert who can talk some sense :p

I fail to see how Kostar is hitting the limiter constantly on a stock engine...
You must be going down hill all the way :S

Benji, can you find those rear sprockets? I looked for some, as I thought that would be idea, but I couldn't find much.
Would you have them custom made?

(Knowing you, you would simply make the whole thing yourself :p )
 

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Haven't got the kit in my workshop to cut sprockets :( wish I had come on santa you know I have been a good boy and deserve a cnc machine :)

I used to find the limiter on a stock engine and gearing, it's all about holding speed everywhere and tucking in, and being very smooth.

As for the sprockets either Talon or Renthal will both do you a custom rear sprocket. The front is the same as a Kawasaki AR50/125 ;)
 
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