WEAK SPARK...Peak Voltage? How to test?
A. Cutt
the CDI which helped a lot, as I hardly had any spark before. At least
now I have spark on every kick. Just no hot blue spark. I tested the
resistance of all other components with my meter and they were all
within specs according to the book. How do I test peak voltage when
kicking? If peak voltage is low what is the likely culprit?
Thanks
Andy
etti
comes from battery to the CDI. If you encounter a voltage loss there, you
get that loss thousend-fold on CDI output. That should do the trick.
Additionally, replace spark plug, spark plug wire and spark plug adaptor,
whichever has a resistor built in, as they can suffer damage which manifests
itself only when high voltage is applied.
Hope this helps.
Etti
A. Cutt wrote in message <3819250F...@jps.net>...
EMARPLE
>Check battery voltage and more important check voltage on the wire that
>comes from battery to the CDI. If you encounter a voltage loss there, you
>get that loss thousend-fold on CDI output. That should do the trick.
Maybe I'm wrong here, but I doubt if a CR has a battery. Even the '85 model. I
suggest having the stator rebuilt if you still think you have a problem. It's
relatively inexpensive (about $125). Maybe replace the ignition coil too. But
I'd be curious to know what other symptoms we are trying to cure other than a
spark that just isn't "hot blue". Usually a dirt bike will run fine on a fairly
wimpy looking spark.
Everett
'91 KX301...(tree-finder)
'74 BMW R90/6...(gentleman's express)
'75 Kawasaki 400 S3 two-stroke triple...(basket case, for sale, $600)
Mark Nelson
Go with the simple things first. Remove all pieces that provide a ground.
Clean the mounting surface and remount. Take the flywheel of and clean that
and the rotor surfaces. On some bikes you can remove the plug wire others you
can't(like yamahas). You might replace that if possible. Also check the plug
cap. Sometime the wire burns back a ways. In the begining it can still jump the
gap, over time it cant. You can take it of and trim it back half an inch or so.
After you've done all this free stuff let us know if it's still acting up.
Pekka Hänninen
>the CDI which helped a lot, as I hardly had any spark before. At least
>now I have spark on every kick. Just no hot blue spark. I tested the
>resistance of all other components with my meter and they were all
>within specs according to the book. How do I test peak voltage when
>kicking? If peak voltage is low what is the likely culprit?
You should make a spark jump test. If the spark jumps > 10mm in open air,
you have enough spark voltage. If your spark voltage is too low, the engine
will misfire at full throttle.
--
Pekka Hänninen, OH7XC
97 KTM125EXC, 95 RM125
A. Cutt
etti wrote:
> Check battery voltage and more important check voltage on the wire that
> comes from battery to the CDI. If you encounter a voltage loss there, you
> get that loss thousend-fold on CDI output. That should do the trick.
> Additionally, replace spark plug, spark plug wire and spark plug adaptor,
> whichever has a resistor built in, as they can suffer damage which manifests
> itself only when high voltage is applied.
>
> Hope this helps.
>
> Etti
>
> A. Cutt wrote in message <3819250F...@jps.net>...
> >I still seem to have a weak spark on my 85 CR500. I recently replaced
> >the CDI which helped a lot, as I hardly had any spark before. At least
> >now I have spark on every kick. Just no hot blue spark. I tested the
> >resistance of all other components with my meter and they were all
> >within specs according to the book. How do I test peak voltage when
> >kicking? If peak voltage is low what is the likely culprit?
> >Thanks
> >Andy
> >