Honda NSR125 De restriction probs?

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

Hi all, i hav the uk spec nsr125 r1. I have an arrow exhaust and taken off the inlet restrictor yet it only maxes out at 82/83mph. it has the tv78 rc unit and ci626 cdi being a uk spec. has 138 main jet, not sure bout others i think their different from stock, i dont know why and if it makes much difference Shocked

. also sometimes it doesn't like 5-7rpm, goes into like a flat spot. spark plug, b8es standard for nsr so im told, any advice let me know if you need to know anyting else? many thanks to anyone who may answer.

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

the standart plug is BR9ECS which is bull shit (as the BR8ES) , best plug is BR9EIX . about your top speed you probably have 14 in front and 38 rear , i suggest you fit 14 & 36 when it will be time to change sprockets .
carbon petals will give a better rate to the engine and set the throttle needle at 2nd notch from top
about your problem 5K-7K it's normal with a cold engine , you will get the best power after 5-8 mn warming
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the worst day fishing is better than the best day working

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

so i have the wrong spark plug all together then, wont trust online manuals again then Shocked

. When i talked about this "flat spot" it is when the engine is warm. It acts like it does in a cold flat spot but not quite as chuggy. So what do you recommend because i found i have a 36 rear sprocket also, not sure at front will have to check in a min. thank you !! Very Happy

Gary SuperSprint · Borekit Bruiser Joined: 26 Aug 2008 Karma :

Are you sure you have derestricted it properly? Mines an import so it's full power and it does over 100mph.
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honda cub 90 (stolen), Honda nsr 125 2001 (stolen), present : fully restored honda ns 125 f 1989. Current project, susuki rf600.

steven843 · Renault 5 Driver Joined: 09 Oct 2008 Karma :

yeah, it has derestricted cdi ci626 and rc unit tv78, taken out restricting plate in inlet and put on arrow pipe, 138 main jet and 14/36 sprockets, is there anything you recommend i try? many thanks

MaybeGuy · Super Spammer Joined: 12 Mar 2007 Karma :

baldy · World Chat Champion Joined: 16 Feb 2004 Karma :

sgc1000000 · Derestricted Danger Joined: 01 Dec 2010 Karma :

sorry to reopen an old thread BUT for all those with the same problem they need to be aware there can also be a throttle restriction (basically its rammed full of washers near the throttle grip to prevent it turning all the way)

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

this is impossible !
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the worst day fishing is better than the best day working