NS125 R HITTING POWERBAND TOO FAST?

[Pol Anorl]

Ok ill keep it short-ish
my ns125r randomly hits the powervalve really fast on diff occasions.

Little example of what i mean.

4th gear full throttle.

1 second 2seconds 3 seconds 4 seconds powerband

then when its being wierd 1 second 2 seconds powerband

powerband hits at 8000rpm ish if i ease of to 6000 and slowly open throttle it dosent hit powerband so fast

if i keep it on when it hits the powerband it takes a while from 8000-9000rpm and it still picks up the same speed it would if it was being normal.

example. 8500rpm 50mph 8700rpm 60mph 9000rpm 65mph

barely any rpm change and speed goes up a lot



i dont think the acceleration is any differnt when it hits either time but you really notice when its in a funny mood as it goes through the gears so fast.
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20:30:37 Pyro.: I don't sort of like men, I take every advantage to choke on dick.
Jewlio Iglesias: You live in Liverpool - Chances are, the front door has already been kicked off the hinges

[Paxovasa]

It could be due to the bike not been warmed up properly or if the air temperature is low, then that can cause the bike to feel sluggish.
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Suzuki GSF600 K3 (in the fastest colour, black).

[Vincent]

Intermitent Powervalve problem?

[st3v3]

Is somebody playing about with the clutch lever while riding?

Nothing you say points to an obvious fault.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[TanacoiusD]

Going on your title .. you know where the CAPS button is ..

[lukamon]

go to the honda dealer and say you need a green powerband not a red one. they dont slip as yours is obviously doing.

(on the other hand, pink are supposed to be better but are more expensive obviously)


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killa wrote: Im an ass man myself

[ncrn]

From my experience of owning an nsr the power band doesn't start until 7800rpm (IIRC). At around 6000rpm there is a flat spot on some models which was to help it pass emissions tests. This simply means if you drop to 6000rpm it will be sluggish to get the bike up to speed again.

From what I remember you had to keep the bike in the 8k to 11k rev range for the bike to stay quick, if you dropped out of this the bike would feel slower due to the power valve shutting. The basic operation is that the exhaust port becomes larger when the power valve opens, so more gases escape after combustion, so more fuel gets in, so there is more power. I don't think its unusual for the bike to feel slower when the power valve has closed.

Edit: Its also worth noting that the bike hasn't got tons of torque so if you are trying to pull from 5000rpm in 6th gear it will take you a very long time to get back to the power band, you need to shift gears a lot to keep the revs high if you want it to shift.
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Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[CaNsA]

FFS Guys,

why hasnt anyone suggested replacing the powerbands for each gear....

Shirley that will resolve the issue.


sorry for calling you shirley

[bikersupermot...]

lukamon and cansa ...

if you cant write anything helpful, best not to respond at all. your answers are kind old hat jokes now and bit tired.
the guy has a genuine Q about his bike and we all have to learn somewhere and sometime.
so why not contribute something useful that you do know about and that can actually help another forum member? (maybe thats why u got very low ratings and iv just rated you both down as well)


and hey hahadumball ... i agree with ncrn basically with the 2 strokes bikes, the higher the revs the more power they make - so you need to keep the engine on the boil and in the higher rev range by using your gearbox to keep the revs up ... dont change up the gears too quick ... instead stick to the lower gears, higher revs and more power. i luv 2strokes
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tinybikes

[CaNsA]

[st3v3]

FFS, its an NS not NSR

How is the clutch generally?
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[salty21]

[CaNsA]

[ncrn]

Fail to see how I was off topic but fair enough.
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Past: 55 Sym Jet, 91 ZZR250, 03 NSR125R. Present: 97 ER-5.
https://www.nsr125.co.uk - NSR Owners forum.

[Paxovasa]

[st3v3]

Cant you guys get a room?

I want to find out how the OP got on with fixing it.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[Pol Anorl]

Played with clutch cable tightenign and losening whilst rideing to see what i come up with and its still doing it every now and then.

But now thats not my main problem my new problem is the fact it idles like a bag of crap.

Takes 2-3 more kicks than usual to start it and when its warmed up a bit it idles at about 800rpm? then cuts out in under a second,
nothings been changed and the idle screw hasn't moved ive tried playing with the idle screw but still cutting out.

When i ride along if i hold clutch it at say 60 + 7000rpm the engine will cut out instantly.

It feels as if theres low compression, got new piston kit will be fitting when gasket set comes.

Taken carb apart cleaned it all.
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GOOD GAME BODYGUARD: https://i.imgur.com/8WePGgf.jpg
20:30:37 Pyro.: I don't sort of like men, I take every advantage to choke on dick.
Jewlio Iglesias: You live in Liverpool - Chances are, the front door has already been kicked off the hinges

[st3v3]

Could the mixture screw type ma-bobby play a part?
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[Pol Anorl]

[binge]

Have these bikes got the variable power-valve fitted?
I had a similar problem with my TZR Pit bike. It was a Yamaha, but had the YPVS installed.
Sometimes it would hit the band at a lower RPM than others. And the band always seemed intermittent.

Turned out the actual housing for the powervalve pulley was loose, so that was rotating rather than that powervalve it's self.

I just took it off completely, and pinned the valve fully open.

[Pol Anorl]

[binge]

The proper term for them is an Exhaust valve.

So it will be situated on the side of the head, by the exhaust port.
Basically, it rotates, and has a half moon shape to it. So as it rotates, It opens the exhaust port more.
And as it rotates back, it closes the exhaust port.


It gives you more power down low in the revs when it's close. And more power up high in the revs when it's open.
If it's opening at the wrong time, it will be making the bike perform badly.




Ben

[V2]

Im sure someone will correct me if im wrong but im pretty sure the NS125R didnt have a powervalve, the one in my garage definately hasnt, this may be why the guy is having trouble finding it

[Pabbers]

oops

[bikersupermot...]

does the nsr125 have a "powervalve" type set up in its exhaust?

i had a dt125x and that had a powervalve in the exhaust header. but the bike had no power to move away from the traffic lights but on an open road at high revs it made stacks of power - but something was up with it.

went out a 120 mile an mostly about 80mph an the engine was singing sweet. but next day it ran really badly and kept misfiring and backfiring an i managed to ride it like that almost to the garage an had to push it last mile when it stopped at lights and wudnt restart.
turned out the piston was melting on one side and the piston rings had worn and melted into the piston.

got new piston an rings ... then had the power valve looked at an it had been pinned open - causing the no power when moving off problem.

unpinned it and reconnected the powervalve cables back up and hey presto - bike was back to running the way it was designed and supposed to!. and ok not so fast top end but the engine is still running and not melting pistons!

so if you do have a powervalve setup in your exhaust its worth checking its working ok.
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tinybikes