Honda NSR 125 2004 weak spark

Honda Nsr 125 · L Plate Warrior Joined: 07 Mar 2017 Karma :

Im at the end of my knowledge to try and get my 2004 nsr working again, i was on the duel carriageway doing about 70 when my rev gauge when crazy and then the bike died it the jumped back into life straight after continued down the road for another half a mile and then died all together.

what ive checked so far:

Compression - Yes Plenty
Fuel - 100%
air - yes
spark - yes but very weak
ive replaced my coil, ht lead, spark plug and cap
reed valves - replaced

it still doesnt want to start i may get the odd cough here and there but nothing full on.

can anyone give ideas on where to go from here i personally feelthe spark is weak and a static shock has a stronger kickthan my spark.
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spottedtango · Trackday Trickster Joined: 04 Dec 2015 Karma :

Have you tested the resistance of the coil and leads? only surefire way to know.

The next steps would be to check the battery condition, the pickups and cdi unit. A visual inspection of the wires wouldnt hurt either.

*Also check the wires that go into your starter relay if theres any. I had a ntv do the same thing. turned out the block connector had worked itself loose causing similar symptoms and a walk home in the dark.

Honda Nsr 125 · L Plate Warrior Joined: 07 Mar 2017 Karma :

what should the resistance be?? and how do i test the cdi unit? and what do you mean by the pickups??
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spottedtango · Trackday Trickster Joined: 04 Dec 2015 Karma :

https://www.youtube.com/watch?v=rRQ45lT2d3c

thats for testing the coils, what to look for ect.

https://www.youtube.com/watch?v=4_EFGAFxi1w

testing ht leads.

The pick ups are usually two magnets usually at one side of the crankshaft normally at the generator side. These tell the bike when to fire when the crankshaft gets to a certain point. Ive seen the odd one get gunked up with metal fillings ect. So id check they are clean ect.

* I had a cb250rs with bad pickups/burnt out windings that caused a weak spark condition and intermittent starting

More importantly is to do a quick visual inspection of the wires coming from the pick ups to the main loom for any signs of damage/burning.

To test the cdi you usually need a haynes manual or service manual. You would test the resistance between specific pins. Most people just swap the cdi and see. I will say that CDI failure is rare. Unless your model is known for it, so its unlikely to be that but not impossible.

Your battery voltage should be around 12.6v DC fully charged.

It could also be a failing voltage regulator which I've heard can also cause a fluctuation in rev counter readings but this would either result in an undercharged or boiled battery.

cb1rocket · World Chat Champion Joined: 30 Jan 2010 Karma :

a weak or intermittent pick up coil can cause weak sparks.

(The coil that triggers the ECU/CDI when the spark plug to fires that is)
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Honda Nsr 125 · L Plate Warrior Joined: 07 Mar 2017 Karma :

thank-you for all your inputs after it was mentioned about the pickup coil i tested it and seemed to be faulty, i then drilled the bolt holes a bit bigger in order to move the pickup closer and the closer it got the stronger the spark up until the point i couldn't get it any closer, the spark still wasn't quite strong enough but much stronger than before which tells me that its 100% the pickup at fault so ill now order a new pickup and replace it then hopefully i can get back to riding
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