Please help get me up to speed!

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

Hi. This is my Honda NSR 125 RX. It's a 1999 model.
https://i232.photobucket.com/albums/ee145/josephgriffin/nsr002.jpg
I'm hoping that someone will be able to tell me what's wrong with it (apart from the scratches). When I start it up in a morning it's ridiculously smoky and there is a major flat spot between 5000 and 9000 revs. This goes after a few minutes but could it be indicating a more serious problem?

Also, my top speed is about 65mph and 0 to 60 takes probably 12seconds, which seems slow when nsr125.com says is should be 100mph and 5seconds. The restricting plate in the intake tract has been removed and this is the exhaust...
https://i232.photobucket.com/albums/ee145/josephgriffin/nsr001.jpg
Am I right in thinking that it has been deresricted? I don't know about the reed valves and carb jets as there is no service history - will these make much difference? How much difference would drilling the airbox make, apart from noise? That's one thing i can do.

Around the exhaust there is sooty, oily deposits (you can see it on the picture). I guess this is probably related to the problem. The power valve seems to be OK - at least it seems to make the right movements.

Also, will the bike pass its MOT if it has been deresricted? It's coming up soon.

Joe

alun111 · World Chat Champion Joined: 31 May 2007 Karma :

sounds like it's burning oil! If you're not great with mechanics i'd suggest taking it to a garage, or if you're careful and have a haynes manual i'd suggest giving it a go yourself aslong as you don't need the bike on a daily basis.

Best checking the pistons, piston ring and valve adjustment things like that i would have thought.

Someone else on here could probably give better advice, just thought i'd give you my two cents.

As with the m.o.t, i would imagine it would pass as i'm fairly sure you can ride derestricted after you've passed your test, and obviously the mot tester won't know this. Someone will probably correct me on this though.

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

One thing i'd like to ask, why are there holes drilled into the end of the exhaust? Being a stroker i think that might be causing some problems... When i de-restricted my nsr exhaust i didn't end up with holes in the end of it..... Have they actually derestricted the exhaust properly or drilled some holes in the end of it?

Oh and it will pass an MOT despite being derestricted.

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

Also, have you removed the restrictor on the carbs? It sounds to me like the bike just hasn't been derestricted properly/at all....

The oily sooty stuff on the exhaust is normal, well it was on my nsr and the 2 that my mates owned..... It burns the oil and makes a lot of smoke being a stroker so i think that's ok.

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

I don't know if the exhaust has actually been deresricted. How could i check? It's all been painted over so i couldn't take the end off without getting a hack saw on it.

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

Well, if it's only going 65 mph then i'm guessing it hasn't been derestricted but it would be my guess that whoever has done that to the exhaust has knackered it.....

Have you taken a look at this sites NSR derestriction guide?

https://www.nsr125.com/derestrict.htm

Everything you need is in there. One thing to note, if your bike is an import you will more than likely have a restricted ECU, this can be a pain in the arse to replace.

Have you seen that guide though?

That guide derestricted my bike along with 2 others that my friends owned and we were all seeing 100mph indicated so it does work.

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

veeeffarr · Super Spammer Joined: 22 Jul 2004 Karma :

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

I don't know whether it's an import. How would I tell that? I have the V5 and it says "declared new at first registration" - if it was imported would that be different?

Should I get my hack saw out? If so, where should i make the cut?

Yeah - nsr125.com's guide is great. That's how I found out about the carb restrictor. I just assumed that the exhaust was already derestricted.

Thanks for your help, by the way.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

You need a lot of drills and a lot of time to take the restrictor out of the front of the exhaust. But even then it should do more than 65mph when restricted. You won't get it to 5 seconds 0-60. 7 to 8 maybe.

If you lift the seat up you should hopefully find a sticker with lots of country codes on it, one of which should have a hole punched in it to say which market it was built for.

All the best

Keith
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andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

The only codes under the seat say...

NSR125RX
COLOUR NH-1
CODE NH1E

Can you tell the country from that?

I'm not that bad with mechanics, but I don't know anyone who's any better - that's why I'm here.

andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

Is my exhaust standard? It doesn't look like this one in Korn's guide at the moment...

https://www.nsr125.com/zorstholes.jpg

Would i be right in cutting it along this line?...

https://i232.photobucket.com/albums/ee145/josephgriffin/Copyofnsr001.jpg

Surely then I would be able to see the restrictor. But there is another one aswell as this one mentioned in Korn's guide?

Joe

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

Right. I'll have a look as soon as i get chance.

Thanks

Minty · World Chat Champion Joined: 23 Dec 2005 Karma :

Looks like someone has decided to drill the wrong end of the pipe, nice.

Way to fook a pipe.

My suggestion would be to get on ebay and buy another.
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joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

My exhaust has already been derestricted by the looks of it...

https://i232.photobucket.com/albums/ee145/josephgriffin/nsr007.jpg

I thought I was actually getting somewhere then.

Would the holes in the wrong end of the pipe have a detrimental affect on performance though?

Joe

P.S. It wasn't me who drilled those holes - it was like that when i got it.

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

Right.

I might as well start a new post! I now know that there is no intake/carb restrictor or exhaust restrictor, but I still don't know about the jets or valves.

I've just seen another post here that makes me think my bike is a French import (my serial number starts with ZDCJC22B...) So will my bike be electronically limited? If so, what's the best way to fix it? The problem in the linked post was that the servo wasn't working, but mine does.

Joe

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

While it might be restricted in another way it should still be doing more than 65mph.

To be honest first thing I would do is a compression check to check it is healthy (from memory it should be 128psi +/- 14psi).

All the best

Keith
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andrew · Mister Road Rage Joined: 03 Feb 2002 Karma :

joseph.griffin · Renault 5 Driver Joined: 22 Jul 2007 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

It is down, and may well be worth a new set of rings / piston, but I would not expect it to be enough to loose you 30mph of top speed (assuming you are thrashing it, not jut sitting upright and opening the throttle a bit in top).

The compression tester will maintain its reading anyway, even without pressure in the engine.

All the best

Keith
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