ns125 hard to start!

[dave123321]

my ns125rk is hard to start, all the engine is good, e.g top end,bottom end, absolutely no noise or rattles etc.
spark-plug is a tan colour which is good.
once the bike is warm it runs fine except for a flat spot at 6k to 7k. then after 7k it takes off.

i run it on castrol power 1...not the cheap rubbish

to De-restrict it, i took the exhaust restrictions out, and drilled several holes in the air box lid ,as advised to.

the spark plug colour suggests to me that its running fine.

i just need to know which way to turn the pilot mixture screw to make it richer. (more petrol to the pilot jet)

[st3v3]

Screw it all the way in, then 2 full turns back out.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[st3v3]

Have you tried putting a spoon or 2 of petrol in the spark plug hole then screwing the spark plug back in to see if it helps kick it back into life?
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[skatefreak]

Hey,
Once you get the intake and exhaust restriction out the engine is going to breath a lot easier, this also means the jets will need to be uprated to aviod running lean.
These are the standard derestricted jets, but as you have holes in the airbox, the air flow my be higher than standard de-restricted.
The re-jetting will sort out your mixture and should sort out the flat spot around 6-7k, if not you may have to go richer to compensate for the airbox holes.

Best regards

-Jvr

[st3v3]

Intake restriction?

Also, I've never heard of the flat spot on these bikes completely dis-appearing.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[skatefreak]

I wouldnt say my bike 'had' (long story) a flat spot at all after warming up...
The engine would pull from low to mid to high with no real devience untill you hit the powerband and then it would just pull harder...

That being said, the bike was de-restricted/jetted etc by a honda garage (allegedly). That being said, it was pretty abused when i got it, R/C valve pinned etc but putting it back to the way it was it was just fine.

The engine in there now... well thats a different story, runs like a bag of spanners but its getting me around whilst I rebuild my other bottom end... Just have to get round to ordering bearings etc heh.

Could you expand on flat spot?
Does it feel like there is a dip in power between 7.5-8k?

Best regards

-Jvr

[st3v3]

I get the impression you're refering to your bike, NSR125.

I'm refering to the bike that I have, and the thread is about; NS125R.

Different bikes, different engines and different characteristics.
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Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done