CRF 250 2005 No Spark

[goody44]

Hi guys,
I have just finished a rebuild of my crf250R 2005 after blowing the big end bearing. It all went back together fine until I tried to kick it over...no spark. The only electrical related components that I touched during the rebuild was the stator, fly wheel and crankshaft position sensor. I measured the peak voltage for the stator and got 30V (not 100% confident on the accuracy of my meter/peak voltage adapter). The min voltage for this according to the manual is 50V. The only potential problem that I can think of is that the flywheel had a bit of a bang at one point while I was taking it off. I have read on the net that the flywheel can get demagnetized however I have spoken to people that I trust that say the flywheels are pretty bullet proof.
Before I run out and splash money around on a new flywheel/stator can anyone give me some advice on whether or not this could be the problem or have any ideas on some tests or think of anything else that could be causing no spark?

- matt

[Akzle]

check all connexions. twice. then do it again.

CDI test OK?

the flywheel/magneto acts as a sender, it sends AC voltage to the regulator and DC signal to CDI for timing., CDI takes that signal and sends voltage to coil for spark. make sure coil is well grounded, and on common ground with CDI, engine, etc.

test stator.

/2cents

[spanner spinner]

The flywheels are pretty bulletproof on these but the stators arn't check for any connection between the stator and crankcase they shoud be none, check the stator for a ohms reading honda don't state a figure, bit if you know someone with the same bike you could compare readings. if either of these are faulty or way out of scale it's a stator. Honda only quote a votlage output you should have 50 peak volts min. Next check the trigger coil, should have .7v minimum. check all the wiring connectors for bad connections. Next unplug the kill switch as I have seen these go bad for no good reason. then check the input voltage to the stick coil it should be 100v. If there is no out put to the coil can you plug your cdi in to a bike the same as yours to see if it works in the other bike. (better than putting there cdi in your bike as there bike is know to go) if there is voltage to the coil but it is low in direct relation to the figure you got for the stator out put (ie 60v instead of 100) a faulty stator is the problem, if the output is correct test the stick coil. primmary .07-.10 ohm. secondary 4.6-6.8k ohm. also to state the obvious have you fitted a new plug with the rebuild as they can go faulty even if they look fine.

[goody44]

Thanks for the advice!
I've done some more testing and at the moment I am leaning towards the stator being faulty.
I've checked all the connections again..seem fine.
The peak voltage coming from the stator is about 25V which leads me to believe its the problem.
The resistance of the stator is 26.5 kOhm, the only guy i know with a crf has a 2012 so I can't compare it. If anyone else reading this has a 2005 could you please post their reading!!?
Crankshaft pos sensor is 2.2V so thats fine.
The peak voltage getting to the direct ignition coil is 100mV which aint gonna do much good.
Resistance of the primary coil is somewhere around 0.1 ohm and secondary is 5.46 kOhm..normal.
Throttle position sensor resistance is 4.64 kOhm which is standard.

And thats about all there is to measure.
So at the moment I'm hunting for a new stator.
Anyone think I have missed anything?

[Akzle]

good shit.
multimeter FTW
def. sounds like stator.

now: learn how to wind coils...(really easy.. just wind, and count...) it will probably be cheaper than a swap-in.
phone jaycar for winding wire (or any winding shop), find specs for yours. get patient and get to it. =D