crf 250 r 2005 sparking issues.....

[merky369]

first off hi to all

right so having a problem with popping and banging after finally getting my head sorted out ..

sometimes engine will run sweet then sometimes i go to rev and it pops and bangs. ive not had it out the garden yet as cannot ride it as it is. the problem is very intermittent. will work then it wont. with the spark plug out i found when it is working it will spark every kick. then it goes into shut down mode and will either not spark at all or spark once every 5 or so kicks..

after this i went straight to the kill switch and re wired a new one...
then i took the stator cover off to make sure nothing was rattling around in there maybe interfering .... nothing.. nice and clean.....

visually i wsant getting far soo

anyway ive gone to the manual before coming here
and checked all components with a multi meter. i have found everything within spec apart from the direct ignition coil.

(see image attached)

between a - c i am gettin a good reading of 5.5 ohms.

but between a - b i am struggling to get a reading at all. when it does read it will only read on the 200 setting. and it reads 00.2 - 00.3 ??

im not 100% with the multi meter reading resistance.

so hoping for some clarification ?

have i found the problem?

any help would be greatly appreciated thankyou for taking your time to read....
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hear the ping? see the smoke? youve been passed, by a two stroke!

[Robby]

Looks to be an early use of a stick coil on a bike.

When coils go wrong, they tend to misbehave when hot then go back to working normally cold. So the symptoms do suggest a knackered coil.

I'm hesitant to be too sure about this, because an ignition coil is usually a reliable part and there are so many other things that could make it run a bit rough on a recently rebuilt 2-stroke. I also know you cocked up torquing down the head, so I don't know what else you might have cocked up.

If it was me, I'd buy a new stick coil.

[Meatybeaty]

Maybe measure the voltage your getting from the alternator, Peak Voltage Adaptors can be easily made, and cheaply, see here
https://thumpertalk.com/forums/topic/1034259-build-your-own-peak-voltage-adapter/
also
https://cbrforum.com/forum/general-tech-9/peak-voltage-adaptor-156906/

[Sister Sledge]

Is there a coil you can swap over to check? A friend might have one??
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CCM 404 DS

[bikenut]

a - c 5.5 ohms, manual states 4.6 to 6.8 k ohms, meaning from 4600 to 6800 ohms at the temp mentioned.

a - b manual states 0.07 to 0.1 ohm ( so a cdi system ? ) at the temp stated.

so both specs out.

Your meter have has a diode test position, whats the low reading using that.

The a - c reading, you have meter set to what range??

Those home made peak voltage adaptors are easy to make, but since maplins have died, getting the parts may be a bit problematic and expensive, try rapid electronics a "ESR" from memory, the latter being good at mail order.

How much is a new stick coil? maybe intermotor do one, a car one which may be adaptable if the honda one is mega expensive. You could of course adapt a non stick coil with a ht lead and cap, but it must have the same primary and secondary resistance values.
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nuts about bikes

[merky369]

getting over 120 dcv from the coils connector every kick, the manual states minimum 100 dcv. so i assummed the stator and pick up was doing its job... ive ordered a new coil. should be here tomorrow will se if problem persists.

i also tested and the cdi eunit and both was also within spec with minimum of 50 dcv each connector. each kick .


a-c reading meter set to 20k .??
read. 5.63.. as of now

thanks
____________________
hear the ping? see the smoke? youve been passed, by a two stroke!

[bikenut]

ESR.co.uk good for small mail,order electronic bits and pieces.
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nuts about bikes