help needed for sproket size on nsr125

[kenny]

i have a 125nsr i pritty sure its a nsr125rr import but not 100% on it

im needing someones help on a finding out how many teeth on wot size the front driver sproket on them are as my bike will only do 75-80mph top end and im wanting a bigger sproket as im getting a new chain this weekend anyway

thanks alot
,KeNNy
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KeNNy 100cc peugot speedfight 125cc Honda NSR125R 650cc suzuki SV650R 125cc suzuki GZ125 600cc yamaha YZF-R6

[Kickstart]

Hi

With that speed I suspect the bike is still restricted. As such changing the gearing will have next to no effect.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[kenny]

nopeits not restricted i have taken out both restrictors and got a arrow race system and had it jetted up but it still only goes 75-80mph then it gears out

i know they restrict them by putting a smaller sproket on to reduce the top speed
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KeNNy 100cc peugot speedfight 125cc Honda NSR125R 650cc suzuki SV650R 125cc suzuki GZ125 600cc yamaha YZF-R6

[OreoXX]

It sounds like your bike is an import then, because they don't usually restrict the NSRs by fitting a smaller front sprocket. You can try fitting one with an extra tooth, this will give you a bit higher top speed, but will cause you to lose some acceleration. If your bike is an import, replace the CDI and th RC.

[Kickstart]

Hi

A smaller front sprocket does not really restrict it. Just makes it rev slightly higher for the same speed. If it manages 80mph and still manages to pull the same revs in top gear with 1 tooth more on the front sprocket then it will manage about 86mph.

However, given that it is only managing 80 (and so probably not even reaching peak power, probably at least 2000rpm off the red line) it is likely that it could not pull higher gearing.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[theshmoo]

https://www.jtsprockets.com/52.0.html?&L=0&sel_uid=153&p=


Kenny i changed my sprockets about two weeks a go and my bike feel a lot faster i get approx 10mph more at top end speed. My bike is a inport nsr.

i put on the 15 front and the 35 back it only cost about £50 with the chain well worth it in my book mate.
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CBR 1100 blackbird.

[kenny]

[kenny]

[Kickstart]

[kenny]

i know the german import version will only do 80kph and the uk version will do 90-100mph with just removing the the 2 normal restrictors

i think mine is an import so they use a smaller cog just need to find out the standerd size one so i can gear up to that so i can hit 100mph
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KeNNy 100cc peugot speedfight 125cc Honda NSR125R 650cc suzuki SV650R 125cc suzuki GZ125 600cc yamaha YZF-R6

[theshmoo]

The acceleration difference is minimal so very slight.
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CBR 1100 blackbird.

[alains]

for you kenny (again) . german bikes goes like the french one 110 -130 km/h , but they have a law (for young ridders) if you fit a backbox on the CDI (which has 2 more wires) you speed will be limited at 80 Km/h . take the black box off and you get the normal bike . you can download my file (excuses sometimes my bad english) here
https://www.geneva-racing.com/~alains/NSRtips.doc
you will the search we have done since 2 years , and why i know what i am talking about
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the worst day fishing is better than the best day working

[kenny]

[alains]

give me your serial number , i will guide you (something like ZDCJC22..........)
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the worst day fishing is better than the best day working

[kenny]

ive got my new 15 sprocket gear and 35 driven gear and a did x ring chain on order which should be with me today hopefully i'll tell you if it makes any difference on my revs/speed and if it dosnt it wont have gone to lose because i needed a new chain since the one on now has about 2 foot of play on it lol
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KeNNy 100cc peugot speedfight 125cc Honda NSR125R 650cc suzuki SV650R 125cc suzuki GZ125 600cc yamaha YZF-R6

[alains]

you are far too long , the max you can afford on this bike is 2.5 with a "full power" 34 bhp . i recommand you order a 14 front sprocket or a 38 rear sprocket . actually you have 35/15=2.33 and you will never use the 6th gear except downhill. 35/14 is 2.5 , 38/15 is 2.53 . if you have not open the package , change it by 14x36 (2.57) which is far enough
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the worst day fishing is better than the best day working