nsr 125 r not running right

[shakey0465]

I have just purchaced a 1995 nsr 125r. It seems to have a problem though, I will try to explain as best as i can.
The bike starts fine, revs fine all the way through the range when not riding.
now, when pulling away from a standing start, if rpm below 5000, no problem, ample power in lower rev range through every gear, so nice smooth ride upto 55 -60 mph.
if I do a high rpm pull away 9000 rpm then again no problem until i get to top gear and then you notice the lack in power to keep it there and it slows down to 60 mph.
when riding along at 60 mph I have to drop a couple of gears to get into the high rev range 9000 + before it will go any faster, but it seems to really take it's time to pick up the revs.
I have also noticed that the throttle makes no difference between 1/3 and full except for a deep throaty roar from the airbox.

I have checked out the following so far: exhaust has been derestricted, the plate to restrict the inlet manifold has been removed, the jets are as follows 135 main, 40 slow, 65 power.

the needle has 5 grooves and it was set on the bottom setting nearest the point.

the spark plug is a NGK R BR9ECS

the plug is showing signs of running slightly rich

there has also been 6 holes drilled in the top of the airbox.

this is a uk spec bike

the problem seems to be worse when the bike is warm but it doesn't overheat at all, the temp needle sits just into the norm

Not having owned one of these before i am now stuck as to what is going on, I am sure it is mixture related but it can get expensive stabbing in the dark.

any idea's[/i]

[alains]

your needle is not set properly . set it on the second notch from top and have a go . if it's a bit too lean , set the needle in the middle notch , but never lower . stick something on the holes & buy a BR9EIX they are much better
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the worst day fishing is better than the best day working

[shakey0465]

Thanks for that alains, I am off to get a new plug now and will set the needle as you said.

I will let you know how it goes later

phil

[shakey0465]

well alains, it seems to be a little better, still not right though.

I have decided that I am just going to sell the bike on as I would like to get something a little bigger.

I will have to take some pictures of it and post it in the exchange section.

Brief description, no front fairing, dent in top of tank, 12 months mot, 11 months tax, needs tuning, uk spec £600 ovno

[alains]

it's up to you , but you should stick on until end of spring to get more practice and a better time to sell it
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the worst day fishing is better than the best day working

[shakey0465]

to be honest alains, I think i am getting a bit old(40) for a little 2 stroke, I only purchaced it to help a mate out of a bind, put it through it's mot and taxed it, I have a z250 I ride about in the winter months, so I think it will make a nice bike for someone who has a little time to spend on it.

[alains]

i am 62 , and i still love my nsr125
____________________
the worst day fishing is better than the best day working