honda nsr 125 power problems

[eddie v twin]

Hi guys wife has a honda nsr 125 02 model with a gianelli exhaust fitted and the carb resticter removed air filter cleaned and new plug. Problem is it takes off like a scalded cat from from 9,000 rpm but at 6,000 rpm its flat with no real power and you have to drop it down a gear to get it up to 8,000 rpm then it takes off, but if you try to accelerate in higher gears 4th, 5th, 6th it just doesnt want to know below 8,000 rpm like the engine is reallly holding back and wanting to go ???, any ideas guys jetting ( standard at the moment), needle on second notch, float hieght is 22.5 mm, synthetic oil

Eddie

[trafficdodger]

Hi there sounds like you need to have it re-jetted my nsr was doing the same took it to some place in shoreham near where i live and they put it on the dyno and rejetted it and it goes very well now.

Cheers

Nige
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Present bike Yamaha R6

[coolfox1]

Sounds a bit like my NSR - Welcome to the wonderful world of un-restricted nsr's !.

You may be able to curb it by a bit but you will always find there is a power band issue with it, I dunno, I kinda like it !, but then I'm a bit psyco lol and like the edge that it gives it !.

Like it's been said, jetting it def helped I did mine and it was so much difference, even gave me a bit more noticed power. Also re-built the hole carb and associated add-ons. Seem they collect so much crap.

Mine is pocket rocket from 0 to 5000 and then after 7000 up to 11000 easy 110 (on track of course) mine is most happy when it's having the *** reved out of it

[eddie v twin]

cheers guys any idea of where to start on the jetting ie sizes, and where to get them from ??

Eddie

[trafficdodger]

Hi Eddie
no idea what jet they put in mine but here is a web address given to me when i needed help with mine they will do everything you need for carbs.

www.dellorto.co.uk

Cheers

Nige
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Present bike Yamaha R6

[Annabella]

My NSR was exactly the same.. I just got used to riding it above 8000rpm.


As you describe it was completely flat below 8000. The first time I had the confidence to wind the throttle on that little bit further I "weeeeeeeeeed" all the way down the A5
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[alains]

sounds like your cables are in the wrong places .
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the worst day fishing is better than the best day working

[coolfox1]

[ayfy]

yep my derestricted NSR is the same. first time I rode it after derestricting I was a bit disappointed and found it really weird. Now I've just gotten used to keeping it above 7k if I'm razzing it around.

just out of interst trafficdodger, how much did it cost you to get someone to re-jet it?

[trafficdodger]

Hello mate it cost me £90 to have it dynoed and re-jetted.

Cheers

Nige
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Present bike Yamaha R6

[knockout_bar]

Did you re-jet the carb when you fitted the new exhaust? If you derestrict the exhaust system, you will need to re-jet. We only had to up the main jet on my cousins RCR. Since you say that the power is awful below 8000 rpm. It sounds like the pilot jet (I think). The main jet only kicks in at high rpm (in your case it would seem, 8000rpm +).

Another thing I will mention is that the NSR is a two stroke. Two strokes tend to have their real kick at high rpms. My cousins RCR is pretty poor at low rpm, but when you open it right up it completely wastes my 125!
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[swampy]

[alains]

you are wrong , you need to put : 3 points on the main and 5 points on the power jet . some one said it cost £90 , jets cost £3 each and it takes not more than 3/4 H to change them , very easy DIY
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the worst day fishing is better than the best day working

[eddie v twin]

Hi you were kind enough to give me some advice about my wifes nsr 125 and its power problems, any way The bike is a 2002 derestricted , and fitted with a gianelli aftermarket exhaust, I have altered the jetting from standard 132-38-55 second notch on the needle too 138-42-65 fourth notch on the needle ,but the bike still has problems reving through the 6,000 rpm mark, below that no probs, and in the lower gears from 8,000 rpm it runs well, can you give me some advice on the jetting ie roughlt what sizes because I think it is still running lean, the bike feels like it wants to go but is holding back HELP !!!!

Eddie

[trafficdodger]

Have you adjusted the mixture since you sorted the jets. Maybe that could be your problem. i had mine done new lets and put on the dyno and they charged me £90 but that was for a few other things as well.

Cheers
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Present bike Yamaha R6

[alains]

trafficdodger you look dodgy , he told that he has move the needle position ! this is an error the needle must stay on the 2nd notch from the top , otherwise you get a bad mixture . eddie , an other thing to do is checking the pulley timming . look the joined picture and tell me if it's the same . also sometimes the red/white wire coming from the CDI get a loose contact at the connector (in the back , under the seat) , so the control box has no info about the speed and cannot adjust the valves . do no touch anything , have a look at the picture sequence and report .
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the worst day fishing is better than the best day working

[eddie v twin]

Hi alan when i switch the ignition on it trys to move but doesnt, when i start the bike it moves to high then to low, when i rev the engine it starts to move from low to high at about 5,000 rpm
any good/??

Eddie

[alains]

with key on it is normal , you heard the noise and no movement , this is because last time to turn the key off valves were high (make a test , turn manually the pulley in the middle and after key on , it will move). your sequence is correct except the valves open a bit too early . normally they begin to open at 6500 rpm , this is probably a sign of tired RC valves control unit or a false info from the CDI . what i will do first is to check the base guide timming on the barrel ( look the workshop mamual) , then the pulley timming .
the valves are closed at low revs to keep a good torque but over 7200 rpm , you need the max openning of the exhaust to get best exit of the burned gas
if you find cheap bits on breakers or ebay , change them . but just a thing , you must know which type of electronics is fit on your bike . you can pm me your serial number (begin like this ZDCJC22..........) and i will tell you if it's a uk, it or import one .
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the worst day fishing is better than the best day working

[eddie v twin]

Hi alan what would you recomend for size of jets for my bike roughly??, as a base setting ??

Eddie

[alains]

if it's a uk or it bike 138,42,65 and carbon reed
if it's german , swiss , french import 135,42,60
are you able to read french ? if you want you can download the file i've put on my forum
(you can also go to https://world.altavista.com/tr and translate it)
https://www.geneva-racing.com/~alains/infos.doc
if you want further infos pass me a pm
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the worst day fishing is better than the best day working

[eddie v twin]

Well I have checked the power valves and it lines up perfectly, on the jetting . I have fitted 138-40-60 the bike now seems to pull through the 6,000 rpm mark but with hesitation then revs cleanly afterwards. I'm gonna try a 140 or a 142 next tried a 145 at it was terrible

Eddie

[alains]

138 is enough , 42 will give you a better start , but which important is the powerjet , it starts to be effective at 8000 rpm , you should fit 65 as i suggested before . mine is a 1998 rebuilt on uk specs and a jollymoto exhaust system , and i can tell you the jetting is perfect ! i reach 12000 rpm and 11200 in 6th gear .
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the worst day fishing is better than the best day working

[eddie v twin]

could I ask what sizes on the jetting you are running alain ??, mine is a 2002 with gianelli exhaust and fully deresticted ?

Eddie

[alains]

look above 138,42,65 and i have carbon reed
https://www.blue-oil-france.com/default.php?cPath=210
model 360451 ~£23
fully synthetic 2 strokes oil (motul 600 or castrol tsx)
sparkplug BR10EIX at the moment (hot days) , i change end september by BR9EIX https://www.sparkplugs.co.uk (£6.84 ex VAT)
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the worst day fishing is better than the best day working

[eddie v twin]

Which part of the jetting on the carburettor would actually control the fueling at about 5,500- 7,500 rev rage ??

Eddie