Bike will tick over but not rev at all. Nsr 125 Jc20 1992

[Bluey]

Hi. Please can someone help me to get my nsr 125 jc20 to run properly?

It was bought as pretty much a basket case. It now starts but will only tick over.
Any excessive movement of the throttle & it will stall.

The cdi unit has a 4pin & and a 2pin connector, & and a single white & green wire.
Which should go to the kick start safety switch (but there is no switch on the bike)

I have changed the 3 carb jets. To what was recommended. Which made no difference. Have also swapped the complete carb, coil, stator one at a time from a running Nsr. Which all made no difference at all.
Has fresh petrol. Inlet manifold is good.

When my sons nsr is switched on, the power valve motor tweaks to the left & right.
Before engine starts. Mine does not attempt to move. I have checked the motor directly to a battery. It will then move left & right.

I am hoping somebody can shed some light or give me some other ideas to try please.
I would really love to participate in the Glastonbury RITS ride out this year, rather than again being a spectator.

Thank you for reading.

[alains]

try to clean any terminals with a special spray for electric contacts
the 6 on the CDI connector
the black/yellow on the coil
afterwards ,fit a new BR9EIX and do this :
- avoid to do this in brightness
- put the plug on it's cap and let it laying on the head
- push start button for few seconds and observe the plug
- the sparks should be blueish otherwise you have ignition problem (generally stator problem)
keep me posted
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the worst day fishing is better than the best day working

[ART-ADS]

personally id use your sons bike and use it to diagnose the issue, so swap parts until one of them is proven to cause an issue. unless I've misunderstood and you have one machine
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98' RZ50, 92' H100S2, 03' VT125, 59' Jubilee 250, 05' varadero chop,

[bikenut]

As alains says.........but.......

I would either use the red neon plug cap ht indicator, it flashes when ht passes thru it, so can be used when engine running as a good visual indicator of ht strength and loss, or, make a tester with good contacts, as cdi system do not like "IFFY" contacts.

You could make a tester with some nails and wood, or plastic and bolts, or similar, setting the air gap and having good contact with ht lead and earth, earth via a wire and croc clip to bikes earth/frame etc..

Or, using a good old plug, screwed or welded to a metal strip, with a flying earth lead and croc clip etc., so no loss of contact when cranking engine via starter motor or k/starter.

Some effort needed yes but tools made for future use.

This of course rules in or out ign problems, you have a multi meter and can check cdi coil and stator ??

Done any frame painting ??
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nuts about bikes

[Bluey]

Thank you to all that have responded. Very Much appreciated!

I have earthed the single green and white wire and it is now revving... At the moment. So fingers crossed it is sorted.
Thanks