Please help me ... with with my NSR de-restriction

Kordian85 · L Plate Warrior Joined: 04 Apr 2007 Karma :

Hello Friends. Today I tried to de-restrict my NSR. Before that I had read de-restricton guide from www.nsr15.com (workshop). Top speed of my bike is around 75mph, 0-60 about 11 seconds, so as it's written most likely restrictors in the exhaust, intake housing, and a smaller front sprocket. I checked my exhoust and there wasn't restrictior, then I looked to the intake housing a there wasn't restrictor too (that gold intake restrictor). Now I dont know what i have to do .... so Pleasae help me manage with this case.....
Sorry for my English, I'm a young Polish boy.....
This are information aboout my Nsr:
Model: Honda NSR125R.
Year: 2001,
125 ccm/11kW
Nr ZDCJ22B01F240656
THANK YOU FOR JOUR HELP

5NSR · Derestricted Danger Joined: 05 Apr 2007 Karma :

I have the same bike..... only older Wink

I went on the same site, and i found the best think i have done for mine was buy a full arrow race exhaust system, second best thing was getting the sprockets changed at a garage for higher top speed, third thing has to be my K&N air filter, not much of a boost but a beasty sound, really spices it up a bit.
I also had trouble de-restricting, in the end i found the restrictors, took them out and there wasnt much difference, get some money, and go exhaust hunting, the new powerband will really catch you by suprise Twisted Evil

5NSR · Derestricted Danger Joined: 05 Apr 2007 Karma :

ALSO! I have seen it done on a vespa125, i have to admit i think its a bit stupid, But! 2-Stroke-Turbo Laughing

i am researching into it at the moment, not having much luck. but i wouldnt reccomend doing it unless you want your nsr to go pop.

A video of the turbocharged vespa:
https://video.google.co.uk/videoplay?docid=2683135400295297703&q=2+stroke+turbo

Fragula · L Plate Warrior Joined: 19 Jun 2007 Karma :

Can't say specifically for this bike. I've ridden one belonging to someone else, and done an exhaust/inlet mod, even after informing the owner that it would not do much good.

The real problem with most small two strokes is the actual restriction, which is in the ignition timing.

The only cure is to either make your own, or replace the ignition box with one from a country where the same modell of bike is sold unrestricted.

The problem is the auto advance.. Back in the day if mechanically advanced points, it was a matter of tweaking springs and weights, bending stop tabs etc, and looking at the exhaust gas under load (real complicated, requires a rolling road and an analyser to do it right, though many plug readings can get close results if you have the skills) I suspect the restriction you face is a "ceiling" on the auto-advance, maybe even a retard, or a rev limiter.

A similar mod on an MTX-50 (after, and in addition to, fruitless exhaust port/inlet de-restriction an polishing, case cutting, a reed valve mod, and a different carb entirely) suddenly /over doubled/ the top speed of the bike. Quite unprecedented.

Of course, that left a bike that could go way faster than its brakes and wheels could handle. A dangerous bike.

So go carefull and uprate all over.