www.gpz-305.de

smoothops · Verfasst am: Do Jul 31, 2014 3:55 pm Titel: No spark curse

Hello,
I can use a little help to restore the spark on my GPZ305. I'm on my second year of attempting to bring her back. When I got it, it was running rather rough, but the two wires coming from the wire harness to the coils were joined together. I took it apart for paint and when it was re-assembled, there was no spark, it would not run. I replaced the handlebar starter switch (I felt a zap when cranking the engine), cleaned all contacts and grounds and re-joined the coil wires, but to no avail. I took away the bridge between the 2 coil wires and decided to try and get the ignition system working as designed. I replaced the pick up coils and there was no change. At that point I noticed that if I disconnected the right coil, then the left coil would give a spark. Conversely, when I disconnected the right coil, then the left coil would give a weak spark. I then replaced the CDI unit, but same happened, spark on one side if the other side was disconnected. The wires to the coils showed 3.5 volts when the engine is cranking. I replaced the stator with one from a KZ305 (same engine, stators looked identical, but different CDI part numbers) and no change, one sided spark as long as the other side is disconnected. However, this time the spark is strong, even makes noise. I also replaced the wire harness and tried with one extra coil, but nothing has changed. I just ordered the voltage regulator, as this is the last part of the electrical system that has not been replaced. On one post in the forum, I saw that the white wire to the CDI is not supposed to have ground when the ignition switch is on. My white wire has ground in both on/off switch positions. However, my CDI does not have the brown wire. One odd fact is that the original CDI unit does not spark at all after I replaced the stator. To recap:
1-there is spark on one side as long as the other side is disconnected
2-all ignition components have been replaced, except the voltage regulator.
3-one sided spark got stronger when the stator was replaced.
4-old CDI does not spark at all after replacing the stator. New CDI has the same part number as the old one, 21119-1061
5-all contacts and fuses thoroughly cleaned, there is one wire that has an empty double connector, comes out of the harness by the fuse box.
6-I will not quit trying until this bike is running

This is how I found it:

http://i960.photobucket.com/albums/ae85/fastbread/GPZ%20305/008_zps97a5ca06.jpg

This is how it looks after paint

http://i960.photobucket.com/albums/ae85/fastbread/GPZ%20305/WP_000202_zps244a178f.jpg

Added a chin spoiler from a Honda Interceptor

http://i960.photobucket.com/albums/ae85/fastbread/GPZ%20305/WP_000328_zps0315e3cc.jpg

Another view
http://i960.photobucket.com/albums/ae85/fastbread/GPZ%20305/WP_000197_zps9d758beb.jpg

I have more pics, including a couple with the bike all assembled, will post when I'm able to dig them out. Any and all replies are very appreciated, I'm all ears.
Regards from Cornwall, Canada
Fred

Lothi · Verfasst am: Fr Aug 01, 2014 9:56 am Titel:

Hi Fred

CDI runs completely independently from Battery and 12V on-board-electronics !

Lootk at wiring diagram:
http://www.gpz-305.de/img/Dokumente/Schaltplan_EX305-B2-3.jpg

Stator has 2 extra-coils for CDI: douple wound with centre tapped.
One is "power supply" for CDI-"Processor"; low voltage, the other ist "charging" the Capacitor in the CDI (high Voltage; about 400V)
There is no seperate regulator or other, coils go directly to CDI

To Stop engine (ignition switch or kill switch) is to "shortcut" one coil to ground !

What to test:

Preparation:

unplug CDI
unplug 8pin connector from alternator (frame brace from alternator upward to seat)

Measure

8-pin connector to alternator:

Black-Red-White: under no circumstances any contact to ground (frame)
Black to Red: about 250 - 400 Ohm
White to Red: about 2 - 8 Ohm

8-pin connector to CDI:

Black or Red: under no circumstances any contact to ground
White: no ground if ignition = on and killswitch = off

connect 8pin-connector together; measure other connector at CDI (CDI still disconnected); ignition on, killswitch off:

Black-Red-White: under no circumstances any contact to ground (frame)
Black to Red: about 250 - 400 Ohm
White to Red: about 2 - 8 Ohm

If CDI serves only one ignition coil it looks like unsufficient power from Alternator - or poor ground contact of CDI (

Remember: Black - Red wires supply CDI with High Voltage (about 400V AC or so)
If cables-insulation has littel damage somewhere it could easily "shortcut" or weaken the amount of charge of the high-voltage-capacitor of the CDI.
So check insulation of black and red cable accurately as the connectors in the 8pin-plug

Sometimes there is mudd-grease-rust between the contacts of the connectors which shortcut high voltage, but measurement with usual hobby gauge shows no shortcut (measuring with low voltage)
Same with the contacts of ignition switch:
remove it, open case and look at the contact plate. Most likely there is mudd-rust-grease.

Before reasembling use pure vaseline (white) to lubrificate and insulate the contacts. Also apply on 8-pin connector ( with Q-Tips or so)
Vaseline must be pur, from pharmacy, "for medical use only ", not from hardwareshop or from manufactur "Vaseline InC." !
_________________
Grüsse

Lothi tach

smoothops · Verfasst am: Sa Aug 02, 2014 11:16 am Titel:

Thanks Lothi,
I will do as outlined today, will post results.

smoothops · Anmeldungsdatum: 31.07.2014 Beiträge: 7 Status: **Offline**

T took the measurements, as follows
8-pin connector to alternator:

Black-Red-White: under no circumstances any contact to ground (frame) NO CONTACT TO GROUND
Black to Red: about 250 - 400 Ohm MEASURED 280-390 OHMS IN SEVERAL ATTEMPTS, METER SHOWS NUMBERS FIRST SECOND, THEN EVENTUALLY GOES TO 0-O.1 OHMS
White to Red: about 2 - 8 Ohm MEASURED 3-5 OHMS IN SEVERAL ATTEMPTS, USING SCALE 20. MEASUREMENT EVENTUALLY GOES TO 0

8-pin connector to CDI:
I HAVE A 6 PIN CONNECTOR TO CDI, NO BROWN WIRE

Black or Red: under no circumstances any contact to ground NO GROUND
White: no ground if ignition = on and killswitch = off CORRECT

connect 8pin-connector together; measure other connector at CDI (CDI still disconnected); ignition on, killswitch off:

Black-Red-White: under no circumstances any contact to ground (frame) NO GROUND
Black to Red: about 250 - 400 Ohm MEASURED 128-362 OHMS
White to Red: about 2 - 8 Ohm MEASURED 1.97-5.14 OHMS

MEASUREMENTS ON MY OHMETER ONLY SHOW FOR A SPLIT SECOND, SO NUMBERS ABOVE ARE FROM THAT INITIAL DISPLAY, RECORDED FROM SEVERAL ATTEMPTS. THE METER THEN JUMPS DOWN TO 0 OR CLOSE TO 0. PERHAPS I'M NOT USING THE METER CORRECTLY
NO VISIBLE DAMAGE TO BLACK OR RED WIRES, TESTED THEM WITH ALL CDI AND GENERATOR PLUGS DISCONNECTED, THEY HAVE END TO END CONTINUITY AND THEY DON'T SHORT TO GROUND.
AFTER ALL TESTING WAS DONE, i TRIED FOR SPARK, GOT THE SAME OLD THING, STRONG SPARK ON ONE SIDE AS LONG AS THE OTHER SIDE WIRE TO THE COIL IS DISCONNECTED. NO SPARK WHEN BOTH COIL WIRES, THE RED/WHITE STRIPE AND THE BLACK/WHITE STRIPE ARE CONNECTED.

Lothi · Verfasst am: So Aug 03, 2014 9:25 am Titel:

Measurement results seem ok except the 0 Ohm result
Please use a 12V Bulb and measue resistance.
If same behaviour of Your gauge Your latest measurements are o.k.
Maybe battery of gauge is weak/too old
If not there must be some problem in cables.

Looks curious all the way
Maybee some independant failures ?
- ignition coil
- CDI or cablestuff.

Please test crosswise and check if failure change side:
(even if You have done so just ago)

left ignition coil to right
left to right pickup

_________________
Grüsse

Lothi tach

smoothops · Anmeldungsdatum: 31.07.2014 Beiträge: 7 Status: **Offline**

Ok I tested the meter with a bulb, seems to be OK, bulb consistently showed the same resistance. I may have had the wrong setting when I measured before. This time I set it to 2K Ohms, measurements were taken at the end, when the number stabilizes. It came with the following
8 pin from alternator:
Black to red .327
White to Red .006
8 pin from alternator connected, ignition ON, Kill switch OFF. measurements taken on the wire harness, at the 6 pin CDI plug

Black to Red .329
White to Red .007

Measurements with the coil leads swapped around show no differences. I also measured the old alternator, showed very similar numbers.

Here is a pic of the meter set at 2K

http://i960.photobucket.com/albums/ae85/fastbread/GPZ%20305/DSCF0004_zps5aefbe2b.jpg

The prior measurements were taken with the setting at 20K.

Lothi · Verfasst am: Mo Aug 04, 2014 4:04 am Titel:

Hi
Measurements are ok Smile

Please test now crosswise runnig condition, sparks must be out of engine, fixed somewhere to ground
Check if "strong" spark changes side or not:
Left to right ignition coil
Left to right pickup
_________________
Grüsse

Lothi tach

smoothops · Verfasst am: Mo Aug 04, 2014 5:52 pm Titel:

smoothops · Verfasst am: Mo Aug 04, 2014 11:53 pm Titel:

Lothi · Verfasst am: Di Aug 05, 2014 6:35 am Titel:

Hi Fred

To abstract:

Symptom is:

Old CDI does not spark after all
New CDI does spark only with one ignition-coil (as load)
changing ignition coils crosswise shows no change in failure
Spark goes stronger when changing stator
Static measuerment shows no connection to ground; resistance of loading coils for CDI seems right

I have tested the Pickups crosswise by unlugging the 4pin connector and tinkering an adaptor (using some junk) in between.

I've seen defective rotors; not from my GPZ305 but from my XT600:
http://www.gpz-305.de/English/Tips/Generator_selfrepair.html
The high voltage coil for CDI is completely separate from 12V board electric system, there is no connection to 12V voltage regulator.
Engine runs even if You unplug the yellow cables for 12V from rotor to 12V regulator

The typical failure in rotor is that the high-voltage wire is shortcut due to vibrations inside the coil
Outside You see nothing !!
Inside for example some wires rasping togehter due to vibration and insolation is damaged-> shortcut, "jumper" for high voltage
If You do a static resistance measurement with gauge it looks well in this case; you can only measure intense mechanical shortcuts (which also can occur)

I will do some theorie:

Basic principle:

conventional coil ignition:
a low resistance coil is loaded directly with 12V at high current
Ignition coil has an iron core; this iron is repository of magnetic field which is charged by high current through loading phase
At ignition time the load current ist interrupted by breaker contact; the "stored" magnetic field breaks down and produces high induction voltage
The "energy" or strongness of the spark depends on the amount of stored magnetic field before.

CDI=Condensator Direct Ignition:
-> A Condensator is preloaded with high voltage (from rotor) and discharged at ignition point through ignition coil.
In discharging process the condensator and the coil builds up an high frequency oscillatiing circuit, therefore the whole pre-stored capacity of the condensator is discharged.
This is also the reason a CDI needs a high-voltage power supply (e.g. 400V AC or more) and has completely different ingnition coils; primary has higher resistance, no usal iron core but some type of transformer core; it acts more like an tesla transformer !
If Condensator is not proper pre-loaded with high voltage before You will get a weak or no spark; same if condensator is damaged by over-voltage.
Or if condensator-primary-ignition-coil couple are not suitable ! (not proper account for building up a good tesla-oscillator)

Typical failure for CDI is often caused by high voltage:

Condensator or load wire (rotator) defective (shortcut) due to electrical surge ; for example running ignition with no spark (=load) leads to overvoltage-lightning inside !!
Or damage in isolation (condensator or rotor), either mechanical (vibrations) or electrical (overvoltage-lightning)

You have changed CDI, after You got some (weak) spark
Then You have changed rotor, after You got stronger spark.
-> looks like CDI or second rotor is also defective.

Or, maybe, some prevoous owner has replaced the special ignition coils by some other sort (for example some type for 12V transitor ignition or so)

-> it would be worth to measure the ignition coils:
primary should be about 4-6 Ohm (Your gauge at "Diode"-symbol)
Secondary (spark side) should be some 15-20 kOhm (Your gauge at 20k)

If it is possible for You try to measure voltage of red-black load wire from rotor (attention, High Voltage !!!)
You must use some gauge with 1kV max at AC (Yours ends at 250V AC which is too insufficient); CDI and spark must be connected.
If You start engine (low revs) ist should nevertheless be some hundred volts AC.
Or You can try an universal phase tester screwdriver for 220V AC, ist should light up !
_________________
Grüsse

Lothi tach

smoothops · Verfasst am: Sa Aug 16, 2014 9:49 pm Titel: