Hi all im new to this forum so please be patient with me.

i bought a nsr 125 r V reg 2000 model

i have derestricted it as follows

air intake

exhaust

but for some reason the bike wont go over 65mph!!!!!!

i was thinking it could be something to do with the cdi or power valve controller

so i have purchased the following items all from a 2003 model

reg/rect
wire loom
cdi unit
powervalve controller
powervalve servo


before i start swapping parts over i would like others views on this any advice that is given will be appreciated


kind regards
mobileguru_2006

Hi mobileguru_2006, and welcome to the Forum.

You say you have derestricted the air intake and the exhaust, but have you checked/derestricted the inlet manifold? There should be a removable plate between the inlet manifold and reed cage with a very small hole - way smaller than the venturi of the carb, that needs to be removed.

You will probably find that this plate is still in place, and is starving the motor at high RPM, which in turn prevents you from reaching MAX speed.

I believe the NSR125R is undergeared from the factory too (I could be wrong - it's not my specialist field!) and can benefit from an extra tooth on the front sprocket. This will also increase your top speed, but sacrifice a little accelleration.

A fully derestricted NSR125R should be good for a genuine 90mph, perhaps a tiny bit more.
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Andy.
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you should have removed this plate from under the intake manifold have you drilled out the restrictor in the pipe? also make sure the rc valves are set right it makes a big diffrance



Other Restrictions
the UK spec bikes do not have restricted CDI units, only the import (RR) bikes have these. The only other way in which the NSR is restricted is that the UK spec bikes have 1 tooth missing from the front sprocket, fitting a larger one will see the bike hitting 110Mph at the expense of some acceleration time. Some bikes which have been restricted as imports have the movement of the throttle slide restrcited, so the throttle is never fully open - to check this have a look into the carb whilst turning the throttle and try to account for all the throttle grip movement.

hi

thankyou for the replies.


i have allready taken that restriction out.
i had one of these nsr`s a few years back and it was hitting 110mph thats what made me think something is wrong with my present bike
errr.....

im also thinking this bike could of been an import where is it restricted through cdi unit so all the parts i listed what i have bought is for uk spec

regards
mobileguru_2006

if your still having problems try getting hold of a 1990 rk (italian import) cdi and rc valve controller Out of all the nsr125,s i have had (and i have had a good few)the 1990 rk was a pocket rocket easy getting to over the ton

i have transfered all the new bits i bought for £50 off ebay

even came with a meta alarm system with fobs worth £200 !!!!

i have transferred all the parts to the bike but not tried it yet so will let you know when i have finnished putting it back togther it starts but not taken for ride yet.


if this doesnt do it what else could it be?

regards
mobileguru_2006

the motor mite need a freshen up

please explain what you mean as far as a freshen up

new cylinder(dont bother getting it replated there only £90+VAT new and they come with a mached piston) and piston rings,rc valves cleaned,crank checked over,new crankseals,sparkplug Ect Ect......basically just a full motor rebuild

well now you mention it i did try a different engine and i got the same speed as i am with this engine

im going to test it out in the next hour so i will let you know how i get on with it.


regards

mobileguru

I'd give my left bollock to see an NSR125 that could do a genuine 110mph!
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Andy.
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ill let you keep your left bollock mate but with the wind in the right direction and a bit of imaginative engineering you can get a well looked after nsr125 upto about 110 ive seen it with my own eyes

I don't think it's imaginative engineering... more imaginative reality!
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Andy.
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the imaginative reality of if is that if your a bit hard of thinking (which i am) you can do some silly things with one to make it do 110 but then it blows up evey time you ride it.................sounds familiar am sure a spent silly money on mine and it did the same thing

Maybe that's where I was going wrong then!

My TZR125 (one of the better 125 motors of its time I reckon) had a Farnham tune and modified carb, a custom made Swarbrick pipe, TZR250 YPVS controller, LEDAR correction kit and Ramax filter, and was re-geared, and that still wouldn't do a REAL 100mph!
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Andy.
NSR-WORLD.COM

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