www.gpz-305.de

Rey · Verfasst am: So Dez 16, 2007 7:07 pm Titel: gpz305 no spark!!!!!!!!!!!!!!!!!!!

jeff keen schrieb:
hi i have bought a second gpz305 (none runner) i have tryed to fault find a fault
when cranking (trying to start the bike i have no spark from either of the spark plugs i have tested for power to the coils which is ok i have narrowd it down to a bunch of wires going in to the crank case (gear leaver side) the resistance isnt hight enough should be (300ohms) could you please write back because i want the bike as a nice christmas present
any infomation would be very helpfull thanks from mark going to test these resistances soon

loading coils:

1) white --> red
2) red --> black
3) red --> chassis (ground)

impulse coils:

4) black/yellow --> black
5) black/yellow --> chassis (ground)

6) black/red --> black/white
7) black/red --> chassis (ground)

please write back with the specification i should have or any other faults thanks Sad

Lothi · Verfasst am: Mo Dez 17, 2007 6:45 pm Titel:

Hi Jeff

typical fault special to the gpz305 is problems with side-stand-switch, clutch-lever-switch and neutral-gear-switch.

Some background about that:

First:
cdi can only run when:

sidestand is retracted
or if clutch-lever is hand-operated and neutral-gear active

Otherwise You have no spark !

This is "controlled" by several switches and a diode-matrix
as a result cdi must always have ground-contact via brown cable.

But this can be country specific.
Here in germany the cdi has these "feature" and a seperate brown cable for that.
Maybe in some countries the cdi can alway run, without that "feature" and there should be no brown cable.
But if it exists, then it must have ground to let the cdi run !

Second:
Cdi has 2 loading or supply voltages:
- one for slow revs (start, neutral)
- one for high revs.
these are two coils in the generator, one big and one small. Therefore resistance is different and not symmtric ! (mechanics often fail at this point)

The igniton-switch "off" gives a "shortcut" to ground to the supply-coil for low revs.
So if You unplug the cdi the white cable is "controlled" by ignition switch:
ignition on --> no contact to ground;
igniton off --> contact to ground

What is also usefull to know:

These two loading-coils have different resistance and also different voltage. They are not symmetric !!
In contrast to other japanese cdi these boxes are very robust and very hard to die
Most mechanics change cdi and generator, confused by asymmetric supply-voltage coils.
But the fault is rarely the box but likely:
- corroded cable-plugs, and by exchange of the box these contacts and cables are touched and shaken by chance.
- Problems with side-stand-, neutral- or clutch-lever-switch and diode-matrix

Measurements

Unplugging generator:

loading coils:

1) white --> red ~ 2-10 Ohm
2) red --> black ~ 200-450 Ohm
3) red --> chassis (ground) on generator-side : none

impulse coils:

4) black/yellow --> black ~ 80-120 Ohm
5) black/yellow --> chassis (ground): none

6) black/red --> black/white ~ 80-120 Ohm
7) black/red --> chassis (ground): none

Unplugging cdi:

seperate brown cable (country specific) has to have shortcut to ground
white cable must not have shortcut to ground in any way if ignition is "on" !

Hint:

Always clean and lubrifricate each plug (when unplugging) with
white or medical, acid-free, Vaseline from a pharmacy !
Use ear-cleaning-tabs for that. never use any anti-corrosive-spray !
The expensive version is to use so called contact-grease for accumlators
but vaseline from pharmacy it is much cheaper and chemically identical.
The two plugs on the way from generator to cdi often cause pain and unspecific faults....
_________________
Grüsse

Lothi tach

Rey · Verfasst am: Mo Dez 17, 2007 7:00 pm Titel: coils

were is the impuls coil located on the bike (wire colour) also the loading coils.
hope fully going to try checking them tomorrow night wb

Lothi · Verfasst am: Mo Dez 17, 2007 7:18 pm Titel:

Hi Jeff

A picture of a pick-up (impulse-coil):
http://www.lothi.org/forum/gpz-305/album_page.php?pic_id=89

Pickup mounted in generator-housing:
http://www.lothi.org/forum/gpz-305/album_page.php?pic_id=153

Wiring diagram is here:
http://www.gpz-305.de/img/Dokumente/Schaltplan_EX305-B2-3.jpg

- 4-connector plug for both pickups
- 6-connector-plug for cdi and battery-charge.

please refer to the wiring diagram.
there You can see also a connection from the white cable to the ignition switch:
the small node if You keep the track from generator (magneto) to the cdi from bottom to top

Btw: some "silly mistake" can be the kill-switch in position "off"
_________________
Grüsse

Lothi tach

Rey · Verfasst am: Do Dez 20, 2007 5:24 pm Titel: sorted

hi i have sorted the problem with the gpz 305
i had an old engine kicking about so i put it next to the other engine and pluged in the appropriate connecters and supplyed power to the bike and second engine to turn it over and it sparked so i swapped the side cover with the stator and pick up sensor in it and i ran the other engine in the bike just have to wait for an exhaust so i can tune and tweek the idle and balancing will probably need halp again soon thanks from mark Very Happy