CDI issue
- Thread starter ca1987
- Start date
crazypj
Split personality, I fake being smart
OK, you've got a new project without fixing the old one.
You really should do an amp draw test on starter motor and also batter voltage while cranking
The idea is to at least find out whats wrong, ignoring the problem is common with 'shade tree' mechanics
If you don't have an amp meter that will measure 80+ amps you can use a piece of 8 gauge cable then set multi meter to millivolts and measure 19.1 inches on the 8 gauge.
That will give a direct reading of amp draw (disconnect battery lead, connect jumper lead and put meter leads at specified distance)
Just about all motorcycles will have somewhere in the region of 30~80 initial amps then settle to 20~40 amps when crank is spinning as the flywheel is aiding to get piston over compression
If your getting 100amps + it shows either engine problem (which we know is OK as it will kickstart) or starter motor/gear train problem
Even if you don't decide to do the tests, it may be useful for others
You really should do an amp draw test on starter motor and also batter voltage while cranking
The idea is to at least find out whats wrong, ignoring the problem is common with 'shade tree' mechanics
If you don't have an amp meter that will measure 80+ amps you can use a piece of 8 gauge cable then set multi meter to millivolts and measure 19.1 inches on the 8 gauge.
That will give a direct reading of amp draw (disconnect battery lead, connect jumper lead and put meter leads at specified distance)
Just about all motorcycles will have somewhere in the region of 30~80 initial amps then settle to 20~40 amps when crank is spinning as the flywheel is aiding to get piston over compression
If your getting 100amps + it shows either engine problem (which we know is OK as it will kickstart) or starter motor/gear train problem
Even if you don't decide to do the tests, it may be useful for others
I fix bikes for a living. The one we're talking about here is my personal bike. That's why I've moved on. The reason I know I didn't do anything wrong is because it's a very simple system that worked exactly as it was and is for many hours of run time before something went bad and no one has been able to figure out what or why. I appreciate your willingness to help but if you're going to judge me, please do not inject your negative personal opinions into the thread. FYI the tendency in our minds to judge others stems from our own fear of self-love and propensity for self-hatred. When you put me down, I feel bad for both of us. I hope things get better for you.
I've got work to do for this current bike, I will run these tests as soon as I have a window.
I've got work to do for this current bike, I will run these tests as soon as I have a window.
Something is obviously wrong but it isn't clear what. We get that the battery and DC circuits are for lights starter etc and AC to the CDI
Comments in an earlier post about CDI output voltage dropping sounded like a failing CDI and it is quite possible that they are all have a similar problem, and that raises the question of whether there's an alternative CDI available.
The other issue that sounds odd is the fact that it starts on the kick or bump and not with the starter. There was a mention of 300 RPM on teh starter and if it's turning the motor at 4300 RPMs it may be insufficient to fire it. Many AC CDI systems reguire the motor to spin at 450 - 750 RPMs to get a spark.
There are all sorts of other possibilities about charge coils creating back EMF and other things I don't understand, so I'll choose to ignore such possibilities.
It sounds as if the starter fails to crank it fast enough to fire and that suggests that the starter may have an issue or it may be there's a voltage drop through the solenoid or button. This is a little subjective but over those 400 miles, dd it always start on the button and if so does it sound like it's cranking as hard as it used to?
The bike should fire up just paddling it.
Comments in an earlier post about CDI output voltage dropping sounded like a failing CDI and it is quite possible that they are all have a similar problem, and that raises the question of whether there's an alternative CDI available.
The other issue that sounds odd is the fact that it starts on the kick or bump and not with the starter. There was a mention of 300 RPM on teh starter and if it's turning the motor at 4300 RPMs it may be insufficient to fire it. Many AC CDI systems reguire the motor to spin at 450 - 750 RPMs to get a spark.
There are all sorts of other possibilities about charge coils creating back EMF and other things I don't understand, so I'll choose to ignore such possibilities.
It sounds as if the starter fails to crank it fast enough to fire and that suggests that the starter may have an issue or it may be there's a voltage drop through the solenoid or button. This is a little subjective but over those 400 miles, dd it always start on the button and if so does it sound like it's cranking as hard as it used to?
The bike should fire up just paddling it.
400 hours I had on that CDI (not miles) - it worked for quite a long time! But I don't think it's the problem despite how replacing it and the ignition coil once made it work for a whole night - about an hour of run time and stopping and starting half a dozen times. The more I tested the more it seemed like that was an anomaly and the problem was with the starter, hence the amp draw tests I've got to do.
300rpm is a pretty fast crank for this bike. Just off the battery it would normally crank at about half that speed and start immediately.
300rpm is a pretty fast crank for this bike. Just off the battery it would normally crank at about half that speed and start immediately.
crazypj
Split personality, I fake being smart
Starter motor will normally be geared to crank around 300 rpm, kick starting is much less actual rpm but acceleration past trigger magnet is high enough for signal to be sent to CDI
One other test that isn't ever mentioned but can be done, operating temperature testing
Friend had access to an autoclave so we could test electronic parts at various temperatures
Many parts that test OK at 68 deg F will fail at 120 deg F
One other test that isn't ever mentioned but can be done, operating temperature testing
Friend had access to an autoclave so we could test electronic parts at various temperatures
Many parts that test OK at 68 deg F will fail at 120 deg F