UP JETTING A HONDA NSR 125 RR

oliverjones19... · L Plate Warrior Joined: 10 Apr 2010 Karma :

I have a nsr 125, ive read in places that its vital to re jet so the engine doesnt run lean, however others have said that you dont need to up jet, providing you keep the standard exhaust and just remove the restrictors from carb and exhaust. Which is the right answer?? Is it easy to re jet?

any help would be appreciated from any one driving a derestricted nsr

oliver!

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

if you have the dellorto PHBH 28mm carb then there is a specific kit for rejetting it. then only thing is, its probably designed to work with all restrictions removed at once.

removing airbox and exhaust restrictions will mean new jetting. i think it will run lean if you dont rejet.

https://www.dellorto.co.uk/merchandise/products_details.asp?PartNo=NSR%20JET%20KIT&CategoryID=2&PartsectionID=24

bear in mind this is only for the dellorto PHBH or PHBL carb.

slyrob · Traffic Copper Joined: 03 Jan 2010 Karma :

just did it myself, the NSR is the first bike I've taken apart and it took me less than 2 hours. You really need to change jets as if you remove exhaust and carb restriction the bike will not run right as Steven said. I put a few pictures on there
https://www.bikechatforums.com/viewtopic.php?t=194685

also download the manual from this thread
https://www.125ccsportsbikes.com/forums/index.php?s=7b632101ad02b235615578d9b7f07330&showforum=10

please ask if you need any help Thumbs Up

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oliverjones19... · L Plate Warrior Joined: 10 Apr 2010 Karma :

When it comes to re-jetting is it just a case of remove the old jets and replace them with the new ones?
Read somewhere that it is hard to do and they have to be turned so many times etc?
Im not sure which carb it has on it, going to have a go at it on wednesday,
you would definitely recommend that i re-jet it tho? how much do you think a garage would cost with re-jetting?
cheers
oliver

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

a little boy can do it !
if your bike is a JC20 (1989-1993) the jetting is OK
if your bike is a JC22 (1993-2001) the jetting is poor
download my file https://www.geneva-racing.ch/~alains/NSRtips.doc and you will find anything you need
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