NSR wierd problem!?!?!

[JakeyC]

hi everytime i start my nsr with choke off and in neutral it revs up to about 4-5 k then dies down and idles at about 1-2k, this normally took about 2-3 minutes.
Now for no reason it revs up to 5k revs then shoots up to 9k then back down then up to about 10k and keeps getting higher
i had to kill the engine before it damaged it self! any ideas??

[Suzuki]

Check your choke isn't stuck open. Cable might have seized?

[JakeyC]

well i have never really known how to work the nsr choke, i am guessing that when it is off it is pushed in and when it is is horizontal and you can see a bit off metal, if it is seized will it explain why it is doing this? i cant see it seizing in one night though

[mr jamez]

Sounds like an air leak to me, could be a sticking thottle cable but if it keep randomly reving itself I doubt it.

Check the plastic hose that runs from the airbox to the carb, make sure it is located properly both ends and is secured on the carb properly. I would say that the rubber intake manifold that runs from the carb to engine is the most likely culprit, again check the jubilee clip. If there are any signs of cracking or perishing you need to replace it, there is also a gasket between the reeds and intake tract. listen out for hissing when the bike is running.

Have you derestricted the bike i.e. taking off the carb and removing the restrictor plate?

I doubt it is the choke, the bike would stall if it was stuck open when the engine is warm, mine does. To turn the choke 'on' push the lever down, to turn it 'off' push it up.

[JakeyC]

nope bike is still fully restricted, but i cant understand this becasue i was literraly riding it last night for about an hour, and there was not one time when any thing was wrong and it rode fine

[JakeyC]

ok this is wierd, just went back out to out after leaving for 30 minutes started it and it was absolutely fine
it wasnt revving right but then it warmed up and was perfect.
the choke must of been the problem because usually when i put it on there was no difference, now when it put it on it revs up and stays at 5k i think the choke was sticky, seeing as though i have never used it, that could of been it. well panick over thanks for the help guys

[JonB]

Maybe the engine was just over heating?
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[JakeyC]

i dont think so the temp gauge was not even a quater way to hot

[mr jamez]

Cool I didn't think it would be the choke, mine just stalls. Consider oiling the cable and checking the adjustment so it doesn't happen again

[Fellony]

Ah don't worry! it's done it a couple of times on my NSR, not many. it'll do it for two seconds or so before bringing itself down to 4k, or at least it does with me.
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[JakeyC]

well panick back on the problem is happeneing again, i noticed that if you push the choke in all the way so it bends backwards a little bit it goes back to normal, whenever i put the clutch in the revs fly all the way and redline this is driving me mad

[Courageous T]

i had this problem on my ped and it actually started going!
something to do with the carb sorry not much of a mechanic

[JakeyC]

well any help is really appreciated i have had it for just over 1 week and not got to ride it once properly, when i finally get it taxed this happens
it doesnt even take a second to rev up now i start the engine in neutral and it revs all the way to 8k !!! so annoying

[Method]

Remove your seat
take the top off your airbox
remove the element from the air box
use your finger if you cant see, but check the slide inside the caruburettor is fully closing when you open and shut the throttle.

my guess is that the slide in the carb is becoming stuck open or is not closing properly,
if this is the case

smear a small amount of 2T onto the tip of your finger and just wipe it lightly around the slide and the grooves that it slides up and down in
this should act as a small lubricant and help the slide in moving up and down freely.

if the slide is moving freely then check the choke (i cant remember if the choke on NSR's lift the slide up slightly, or if they open a passageway past the slide?) just check the choke lever is operating properly. On my '01 NSR the lever was pulled outwards so it was sticking out for choke on, and pushed down was choke off. make sure you havent got the choke lever stuck out, and that the lever does actually move the arm that it pulls / pushes to open / close the choke.
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CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[Yeti]

i Used to have a similar problem on my old NSR if i was running out of fuel. If i left it on tick over with the choke on to warm up and it was running out of fuel on main the revs would shoot right up then it would just cut out. i dunno how much relivense this has got but it might help.

When you push the choke in it should flick in with out any effort at all. if you have to mush it in then it is seized and may be the problem. If so take it off and run some WD40 down both ends and work it through till it runs smoothly
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[JakeyC]

when i remove the seat all i can see is the battery and a big long sheet of black plastic covering up everything how do i get to the airbox?
thanks for the help btw

[JakeyC]

oh yea i am not running out of fuel so that cant be the fault

[Method]

Oh ok sorry mate its been a while since i had my nsr
if you undo the little alan key bolt that is at the front of your tank and before the handlebars, on the right hand side, you can pull that bolt out and the tank will lift up, theres a car bonnet style holder you can put in place to keep your tank in the air, and theres your airbox
____________________
CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[JakeyC]

right well its a bit dark now so i will give that a shot tommorow first thank thanks very much for the help

[Method]

no worries, i hope it helps!
i know with all my race bikes that a stuck open throttle is the main cause of revs flying up like that all the time. another thing you might want to try, if that doesnt work, if you still have the tank up and everything else is fitted back (not inc. the seat obviously ) then you might try starting her up, if the revs shoot up still, just try giving a tug on the throttle cable where it enters the top of the carb, just little pulls to see if its become stuck and needs freeing... another idea ^
____________________
CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[Method]

any luck?
____________________
CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[JakeyC]

yea thanks for your help, my dad ex mechanic troed everything you said and in desperation gave the carb "piston" if you will a clean and greased it, and UM VWALA! 100% working now, and riding better than ever before. all this time ive been missin out, we also adjusted the idle to 1500K revs.

[Method]

Yeah, so it was the slide or "piston" getting stuck then, ah well. Well done! glad to be of assistance
____________________
CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[Aikman666]

Funnily enough the exact same thing was happening to my bike. Was really easy to notice though, seen as the throttle grip was extreemly loose and wasnt pulling on the cable. Good job on fixing it
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