NS125f Performance issues

[SpannerMonkey]

Currently riding an NS125f at the moment and It's pretty apparent that while to me it feels like a missile (Not used to anything capable of over 65mph) it's definately restricted. I remember seeing elsewhere a post from Kickstart (on visordown I believe?)
And the content was basically that the ATAC system and anything relating to its existence VANISHED. The airbox is shite... the standard pipe again... is shite (Luckily I have a Micron) and lastly the CDI is about as much use as multi-use toilet roll
Am I missing anything here? I'm not going to fish about for the full power parts but I might find me a compatible CDI and a good second hand air-filter with suitable jets.

[SpannerMonkey]

Anyone?

[Kickstart]

Hi

Airbox wasn't part of the any restriction, just seemed to be a poor design and one where people did get half decent gains from a single filter.

Not aware of any ignition restriction.

The real restriction was just in the exhaust, and with a Micron you should have that solved.

The ATAC operating system is missing, but not a major issue. For high revs the chamber should be closed, so you can blank it off if you want. However on the NS I have been told it is blanked off as standard (wasn't on the older MBX125 engine).

All the best

Keith
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[SpannerMonkey]

[Kickstart]

Hi

Real top speed restricted was in the low 70s, with rather more on the speedo. Didn't take much to get them indicating a lot more than 80.

Is the Micron damaged? Has the jetting been played with? Has someone opened up the ATAC chamber? Is compression reasonable?

All the best

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

[SpannerMonkey]

[Kickstart]

Hi

Exhaust should be fine then (assuming it isn't seriously coked up).

ATAC chamber is cast into the barrel and head. It should be closed off at high rpm, but UK ones didn't have a mechanism to open / close it. However I have been told they were closed on UK spec ones, so possible someone has opened it up. Without crawling over it not sure what the easiest way to check is, but wouldn't expect a massive difference either way.

Workshop manual lists it as a 110 main jet. Make the mixture too rich and you lose power (make it too lean and you seize the engine).

All the best

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

[SpannerMonkey]

[Kickstart]

Hi

It is a slide carb and they do not work well if you just ram the throttle open wide. Open it progressively with the revs.

However that it gains power when the throttle is backed off does suggest the jetting is a bit off on full throttle.

All the best

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

[stirlinggaz]

hi,
you would be able to tell easilly if the atac had been messed with.
theres 2 blanking cap on side casing & side of cylinder at 90degs to each other., about size of 10p, thats where the atac mechanism (it looks like a thin rod coming out of cylinder & connects to a little lever coming out from gearbox/oil pump drive) would be on the foriegn bikes.
these would need to be drilled open to fit in the atac assembly & its financially not viable. (trust me on that,lol)
the herp chamber (iirc) is the pipe shaped thing on top of cylinder, make sure the little phillips screw is still there & the pipe is tight.
mines used to indicate 90mph with changed sprockets, open air filter & micron.
de-coking makes a huge difference, as does good compression!
might just be needing new rings?
cheers,
GAZ
ps im thinking that you have the standard sized main jet & this needs to be changed?
have you done a plug chop?

[SpannerMonkey]

[N cee thirty]

plug chop simples

get bike up to temp,go for a quick ride and cut the ignition and roll to a stop and then take the plug out and see what colour it is
____________________
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Jewlio Iglesias wrote: I actually did vote BNP once

[Kickstart]

[G]

If you get a really long straight and max it out, what speed do you get?

[SpannerMonkey]

[G]

Think the best I had indicated on my NS125R was 88 and that was on an airfield (actually was ) lying flat.
So doesn't sounds like yours is too bad in that regards really.

[MarJay]

[Kickstart]

Hi

Think an indicated 100 was pretty common (speedos were compulsive liars though).

For comparison my old MBX125 would just squeeze off the end of the speedo (last marking was 90mph, needle would get to were 92 would be). Never had it weaving though even when burried under luggage.

All the best

Keith
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