NS125 tuning

Keen · Guest

I'm seriously thinking about getting an F reg NS125 that I've seen for sale, but I'm worried about the performance not being as good as I want/expect it to be. I heard that the NSR125 will do 0-60 in 7 secs, will an NS125 be far behind this? if so has anyone got any tuning tips?

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Remind me in a few days and I will dig out a tuning article on the NS. Found the NS125R roadtest last night which comments on the tuning article for the NS125F. Says that with a decent pipe it produced 19hp, going up to 21hp with a single air filter

All the best

Keith

Keen · Guest

thanks

Guest · Posted: 13:29 - 23 Feb 2002 Post subject:

also, is 40,000 too much for a 2-stroke? I've seen a cheap bike with that milage, its MOT'd and supposed to be in good condition, but is that kind of milage too high?

TJ NSR · World Chat Champion Joined: 03 Feb 2002 Karma :

WOW

tats a bit toooooo high mate, it must of had 3 rebuilds,

dont bother bruv

ilovens125f's · Renault 5 Driver Joined: 20 Sep 2003 Karma :

Keith
Could you get the tuning tips for the ns125f (because i have one)
i want to tune it up and make it go fast
Thanks Kev
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Kev the Ns125F lover!!
!!!Dont ignore me!!!

Scotty · Scooter Boi Joined: 31 Jul 2002 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hex · Party Boy Joined: 04 Feb 2002 Karma :

Syfoon · TRUCK!!! Joined: 29 Apr 2003 Karma :

Ah, burning wasps nests. Great fun!

Lighter fluid works best, but you get stung like a git trying to finish the job.

Found the best way was to firebomb the nest...

... although thats not really a good idea for Keith to use Razz

.
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Not here...

Scotty · Scooter Boi Joined: 31 Jul 2002 Karma :

Yes imagine that,

empty bottle of gin,
Filled with petrol,
One useless rag also doubted in petrol.

lights rag...

opens loft,
"muahahahaha See you in hell wasp's!"
//Quickly throws bottle...and cloese loft.

Walks away all snug and proud,

turns round to realise the house is on fire.
Hmmm damn...
Carries on walking ..i'm sure it insured...
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Regards
Scott

Kickstart@Work · Scooby Slapper Joined: 26 Sep 2003 Karma :

Ste · Not Work Safe Joined: 01 Sep 2002 Karma :

Impressive. Will your council not come and kill them for you? They have done all ours (normally 2/3 a year Confused

)

Still havn't found that hornets nest which is nearby Shocked

Kickstart@Work · Scooby Slapper Joined: 26 Sep 2003 Karma :

Hi

They might come out, but most places say just to leave them unless they are causing a problem. These are keeping themselves to themselves so can stay there for now.

Don't think wanting to look at some old bike mags would count as them causing me problems.

All the best

Keith
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Atheism is a not for prophet organisation

James · Spanner Monkey Joined: 25 Feb 2002 Karma :

I used to own an NS125F which i tuned to the limit. The bike responds well to tuning, but it does require quite alot to get it upto scratch.
First thing you wanna do is either derestrict the standard pipe, or whack a race exhaust on. Secondly you wanna completely take out the standard airbox and fit a K&N. Once you have done this the bike needs re-jetting to make it run right. as i remember you only need to go up a few sizes (about 5?) on the main jet, and you get better throttle response if you go leaner with the needle clip.

Once you've done that, you wanna get your cylinder head skimmed. It doesn't make a massive difference but it does make a difference. I wouldn't recommend forking out for racing reeds as they make virtually no difference. If you do all that and get it running tip top, you should be looking at between 85-95mph.

Have fun....
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Like shit off a stick

malc · Two Stroke Sniffer Joined: 03 Dec 2003 Karma :

Hi,
I have an old K reg ns125 and it already has a high performance exhaust but am interested in the aircleaner change.. Is this the sort of wire grid spong type? Any suggestions where best to get one and how much?

I bought the racing reeds and did very little Sad

The engine is quite flat up to about 4K rpm and then improves to about 6K and then flies.. I would like to normalise this a bit so that it runs better at the lower revs.. any ideas?

If anyone has ns125 spares, particularly a spare complete engine, I owuld be interested as it woudl be better to build and tune the spare than keep stripping the working bike.

Thanks.. I hope to get some advice.. Laughing

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Malc
In search of ns125 Bits Smile

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

The actual airbox on the NS is meant to be fairly restrictive.

The only real way to get the low down power back is to get rid of the performance exhaust. Do that and you will get some low down power but loose loads of top end power.

There used to be an aftermarket power valve that you could weld onto the exhaust. Haven't seen them advertised for years. They were just a valve operated by exhaust gas pressure and at low revs they were open and effectively increased the exhaust port volume.

Best solution would be to find an engine and exhaust from an imported full power NS125.

All the best

Keith
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malc · Two Stroke Sniffer Joined: 03 Dec 2003 Karma :

Hi Keith
Thanks for that input... The bike is an Italian Import. 92 model but still with the square steel frame.

What would I look for in a 'full performance' engine?

I am seriously considering the aircleaner change and upping the main jet. Ideally, I would like an old carb to dabble on so as not to destroy the road bike... Rolling Eyes

Cheers
Malc
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Malc
In search of ns125 Bits Smile

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

If it is an Italian import then it probably already has the full power engine. On the r/h side of the bike (from sitting on it) there is a small cover going from the clutch cover up to the side of the barrel. This opens and closes the ATAC chamber. On UK restricted models this was left off and the ATAC chamber was open (low revs position) all the time.

General trick with the NS was to drill holes in the airbox lid or fit a K&N single filter. Just replacing the filter element will not do much. If you do this it is probably best to up the jetting slightly.

Without saying goodbye to loads of top end power there is not much you can do for the mid range really. However it might be worth trying a normal Honda exhaust rather than an aftermarket one. However avoid the one from the UK spec bikes as they were restricted.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

malc · Two Stroke Sniffer Joined: 03 Dec 2003 Karma :

Hi Keith
Yes, there is a triangular shape cover plate, not opened it so not sure what is in there Shocked

.. will have a look.. I assume it is safe to open and won't shoot springs and thigs out Laughing

Thanks for your advice.
Cheers
Malc
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Malc
In search of ns125 Bits Smile

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

At some point yes it will shoot springs and things, but I cannot remember which bits. Think most of those bits are under the clutch cover.

Basically it is driven off centrefugal force, driven from the primary drive.

It is fully described in the Honda workshop manual.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing