hi all

marc_yorks · Crazy Courier Joined: 13 Mar 2004 Karma :

Just bought an old ns125f,it go's really well when you rev it Smile

Really surprised me,thing is on low revs it misses and coughs a bit.
do you think it just needs a good tune?
I think its been stood for a long time.
Any help greatfully appreciated. Wink

ZaphodBeeble · World Chat Champion Joined: 10 Feb 2004 Karma :

Try cleaning your carbs, get a new spark plug, new air filter etc etc. Thumbs Up

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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

marc_yorks · Crazy Courier Joined: 13 Mar 2004 Karma :

Cheers for that mate.
Are these pretty easy tasks?

nsr125sp · Renault 5 Driver Joined: 04 Oct 2003 Karma :

Yea really easy check out https://www.nsr125.com/service.htm for more help Thumbs Up

Ollie

marc_yorks · Crazy Courier Joined: 13 Mar 2004 Karma :

cheers menguin Cool

Hex · Party Boy Joined: 04 Feb 2002 Karma :

The ns air filter is a washable one, so just was it out dry it and i've it a light oiling.

New Spark plug and fresh fuel and away you go. There is nothing below 7000 rev's on them and theres no power valve so it comes in with a rush. Very Happy

Its not the same as the NSR so the manuals and guides don't really apply.

Hex
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marc_yorks · Crazy Courier Joined: 13 Mar 2004 Karma :

AcIdBuRnZ · World Chat Champion Joined: 28 Jul 2003 Karma :

Hi

Sounds like you are on the right tracks.

I suggest you send a PM to Kickstart, or wait for him to reply here.

He'll be able to help you, I'm sure.

Good luck Thumbs Up

Mark
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Past: Honda NSR125R >> Kawasaki ER-5a2 >> Kawasaki ZZR-600e1 >> Suzuki GSXR-750Y >> Honda VTR 1000 Firestorm
"Chickity China the Chinese Chicken..."

marc_yorks · Crazy Courier Joined: 13 Mar 2004 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

The older NS has no power valve on UK models. The power valve was a chamber on the side of the exhaust port which (on full power bikes) was open at low revs and closed at high revs. Without a working power valve and with a full power exhaust you will have little low down power, followed by the bike taking off like a scalded cat at around 7000rpm

The air filter might well be a large part of the problem. That would cause it to run rich.

However with a slide carb if you open the throttle fully at low revs you will just drown the engine. You need to open it progressively so that you are only using full throttle at high revs.

The idle circuit and the needle jet control the fueling at up to around 3/4 throttle. It sounds to me like you are running rich so you can try adjusting the mixture. The mixture screw changes the mixture at very small throttle openings. The needle jet adjusts the mixture through most of the range. For minor changes you adjust this by moving the needle slightly. The needle is attached to the slide in the carb, and is located by a clip that goes round one of several notches on the needle. If you move the clip further up the needle (ie, further from the pointy end) then you make the mixture leaner, while moving it down makes it richer.

I would try moving the clip up one notch on the needle and see how that goes.

All the best

Keith
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