NSR Rev Hesitation

[OreoXX]

Hi

I have an NSR125 (2001 French) with a Gianelli Exhaust. The bike has loads of power, but between 5000rpm and 8000rpm, it seems to hesitate quite a bit when accelerating. I checked the RC valves timing, and it is perfect, I just fitted a new spark plug too. What could be the problem? A mechanic told me to put the needle on 3rd notch from the top, allowing more fuel for the mid-revrange. Should I do this?

Thanks

[alains]

certainly not . it seems to me that it's more a rc valves problem . you must observe the pulley sequence .
- key on the pulley goes to high
- start and the pulley must go on low if you are over 2000 rpm (especially when you start on choke) otherwise it will stay on high
- accelerate and the pulley goes to high over 6500 rpm
this is because at low rpm closing the valves help a good torque . you can make a test : adjust your idle at 2000 rpm and you will see the pulley going alternatively on high and low
download https://www.geneva-racing.com/~alains/NSRtips.doc (988 Ko)
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the worst day fishing is better than the best day working

[OreoXX]

I have done this several times, it is perfect! I have used your NSRtips document and watched the sequence of the valves, all perfect! No idea where the problem lies

[alains]

the needle must stay on 2nd notch from top . i suppose you are on initial jetting which is main 132,idle 38,power 55 . change those with 138,42,65 . you will get a better start and a better climbing in revs . you have risk of breaking with a race exhaust if your mixture is lean . also fit a BR9EIX , even it's not free , it's much efficient and will save a bit of fuel . i've updated my file yesterday , you will be able to see how dismantling the carb (about 1 1/2 hour to change jets) . can you tell me also which CDI & RC valves control unit you have .
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the worst day fishing is better than the best day working

[OreoXX]

I have done all that! 138-42-65 jets, Gianelli Exhaust, CI626, TV78, BR9EIX, Carbon Reeds! But it says in the NSRmanual that the standard setting of the needle is on the 3rd notch! I haven't checked in my carb yet, but is this true for 2001 NSR125RR from France?

[alains]

if the needle has 5 notches it's correct to set in the middle , but if it has 4 notches , set it on the second from the top . i say that because some of my mates have 4 and some 5 (probably it has changed in 1993) and the workshop book was edited in 1989 . may be you are too rich ! watch your plug
____________________
the worst day fishing is better than the best day working

[OreoXX]

Ok, I will check where the needle is and report back.

[OreoXX]

The needle had 5 grooves, the clip was on the 4th from the top! I set the clip on the 3rd from the top (in the middle) and cleaned the rest of the carb while I was already inside the bike. I set the pilot screw 2 1/2 rounds out, warmed the engine up for 10 minutes, adjusted the throttle stop screw to 1400 +- 100rpm. Went for a ride, the bike has absolutely no more hesitation!!

Thanks for the help!

[John C]

Glad you got it sorted

[OreoXX]

Yes, I was worried something really bad had happened, since the RC valves timing was perfect, but then, hey, the needle was too high! Oh well, it runs like never before now