No spark on Suzuki GSF250 1996

[imthatguy]

Hey, guys, long time no see haha - I recently bought a very cheap GSF250 sight unseen `with issues`... One of those being it wouldn't start.

Turns out it has absolutely no spark.

I'm thinking it must have something to do with the CDI but am struggling to confirm my theory, is there any way of testing that, bar borrowing another bike? (Btw does anyone has a bandit 250 they want to lend me for the day? :laugh: ) There seems to be 12v getting to the coils, resistance over the coils is normal, the CDI is getting power to all the right places, the pulse generator has within spec resistance (though could be another problem), what else can I check?

I should also mention I've tested the coils / plugs on another bike and they work fine. And have disconnected / sorted anything else that could be an issue (side stand switch) with little difference.

Battery is fine I got it form my working and fully charge Kawasaki..

[OddDuck]

OK, it's probably the CDI. Try these though, you'll need a basic multimeter for most of them:

1) Check plugs and look for carbon fouling - blackened insulators. The carbon will short the spark out. You can test for this with a multimeter, set to the highest ohm scale - clip onto where the HT lead goes and the hex on the body of the plug. if you can read anything then that's it, the plug's fouled.

Cleanup is possible via sandblaster / LPG torch / careful use of wet-n-dry around the insulator, but spark plugs are cheap enough to replace.

2) Check what happens with main battery voltage when you're cranking the start motor, if it drops like a stone then you've got a problem in the starter circuit somewhere and there's no juice left over to fire the plugs.

3) Check your kill switch. Strip it, take a good long look at the contacts and the wiring. It's not unknown for these to fail and a cleanup could sort it all out.

4) Check your fuses. Visual and also multimeter ohms.

5) Check that the pulse generator is actually pulsing. You can do this by using a multimeter and tapping into the back of the lead to the CDI, look for ac voltage. Start at the highest voltage measurement settings on the meter and work your way down. If you're still getting nothing on the millivolts ac scales then that's where the issue is. This is the least likely thing to go wrong btw.

6) Take a very careful look at the potting on the CDI itself. If this has gone hard and cracked, and the bike's been stored somewhere cold and humid, you could have moisture ingression. The CDI has some high internal voltages and if water's got in, these voltages will leak, preventing it from working properly. If the potting does appear damaged, put the CDI unit somewhere warm and dry for about a week and see if there's an improvement after that. Rice (as popularised for cellphones) doesn't work, movement of warm dry air does.

7) Check your HT leads for continuity end to end, again using the multimeter. The caps screw into the wires and if this screw connection has corroded or degraded then it could be part of the problem.

8) Check grounding connections through the electrical system - these usually bolt onto the frame or engine. You want clean metal to metal connections.

9) Break and make every electrical connector, maybe several times if the contacts look discoloured or corroded. Use the CRC electrical contact cleaner stuff. Find the main relay and pull / replace it a couple of times too. Do this with fuses also.

Hope this helps.

[imthatguy]

Thank you!! Very much - will give that a try tomorrow :)

[F5 Dave]

When you do get it going


Immediately put a meter over the battery and turn bike off if it goes over 14.5v with a rev. Regulators go AWOL this usually kills, in no particular order; stators batteries headlight bulbs,. . . and CDIs.

[imthatguy]

When you do get it going


Immediately put a meter over the battery and turn bike off if it goes over 14.5v with a rev. Regulators go AWOL this usually kills, in no particular order; stators batteries headlight bulbs,. . . and CDIs.

Will do! Im aware of the rather catastrophic damage a damaged reg/rect unit can do unfortunately.. :no:

By way of an update, tried all this but nothing helped, ordered another CDI, didn't help - the only thing I haven't checked / replaced is the hall sensor so Ive ordered a replacement of that and will post results when I have them.

Cheers, A

[imthatguy]

By way of an update.. I got the new CDI, plugged it in aaaand.. Nothing!

Ive also discovered I was checking the hall effect sensor incorrectly so that is definitely working, Im basically run out of ideas at this stage.

Ive been going off this digram http://www1.synapse.ne.jp/s-hara/bandit/ban-spece.html#electric-ig even though my bike is a '96 model, does anyone know if / how the wiring changed between years?

I know the coils / plug caps / plugs are working because if you run a line from the negative terminal of the coil to the negative of the battery you get a spark on both of that coils two plugs.

I know that the CDI is working because I replaced it.

I know the hall effect sensor is working because resistance is within spec and its generating 5v AC when you crank the bike over..

The only thing going into the CDI are the two negative coil wires, battery negative and positive and hall effect generator negative and positive - what am I missing? There is also a wire coming out with 4.56something volts on it, presumably related to the Taco or some such thing in the dash?

Would anyone with a '96+ model of bandit 250 be able to take of picture of their CDI wiring and post it, or even better know where I could locate a pin schematic? :blink:

[F5 Dave]

By way of an update.. I got the new CDI, plugged it in aaaand.. Nothing!

Ive also discovered I was checking the hall effect sensor incorrectly so that is definitely working, Im basically run out of ideas at this stage.

Ive been going off this digram http://www1.synapse.ne.jp/s-hara/bandit/ban-spece.html#electric-ig even though my bike is a '96 model, does anyone know if / how the wiring changed between years?

I know the coils / plug caps / plugs are working because if you run a line from the negative terminal of the coil to the negative of the battery you get a spark on both of that coils two plugs.

I know that the CDI is working because I replaced it.

I know the hall effect sensor is working because resistance is within spec and its generating 5v AC when you crank the bike over..

The only thing going into the CDI are the two negative coil wires, battery negative and positive and hall effect generator negative and positive - what am I missing? There is also a wire coming out with 4.56something volts on it, presumably related to the Taco or some such thing in the dash?

Would anyone with a '96+ model of bandit 250 be able to take of picture of their CDI wiring and post it, or even better know where I could locate a pin schematic? :blink:


so the cdi was off a working bike? can you plug it into a working bike to be sure?

[oldiebutagoody]

All I can contribute to the discussion is that maybe the voltage drop over the OEM wiring loom (due to age, corrosion, bad or missing connections) is insufficient to power the coils to give any spark (it needs to be a fat blue spark to fire not just a pussy weak yellow spark). You mentioned that when you hook to the battery directly you get spark. Might be a clue to a fix there. Coils require a minimum 11.4v to fire a spark. Its not uncommon for battery to deliver 10v or less by the time it has run the length of the OEM loom, with 20 years of deterioration, minus the draw created by the starter solenoid/motor.

A couple of years ago I bought a gsx 600f 1992, and did a coil wiring mod/direct battery to relay/relay to coils. Its fired every morning since, hot or cold winter. I also pared back the HT leads an inch each and fitted new plugs so no claims to offer a solution. I'm just about to do the same work to my new to me 1996 Bandit 12.

Suzuki wiring problems (rolleyes)

Bypass the loom/startercurrent draw/deteriorated connections on the OEM loom.

Get a 5 pin automotive relay, hook up direct to battery (positive), insert a 10 Amp fuse, ground earth pin on the relay to frame using same bolt to mount relay in a convenient hole somewhere near. ( IIRC) Take the two orange wires off coils and use one on the switch connector pin on the relay, and connect two wires from pins 87 to the coils where the orange wires came from.

If that does not fix it, it has to be fueling related, or again back to the CDI.

Wiring used should be 15 amp guage or heavier, and all parts shouldn't run you more than 50 to 60 bucks if you hunt TM etc rather than repco or supercheap.

[imthatguy]

so the cdi was off a working bike? can you plug it into a working bike to be sure?

It was purchased from Wayne at bike busters at no small expense and he said it was from a working bike yeah..

[imthatguy]

All I can contribute to the discussion is that maybe the voltage drop over the OEM wiring loom (due to age, corrosion, bad or missing connections) is insufficient to power the coils to give any spark (it needs to be a fat blue spark to fire not just a pussy weak yellow spark). You mentioned that when you hook to the battery directly you get spark. Might be a clue to a fix there. Coils require a minimum 11.4v to fire a spark. Its not uncommon for battery to deliver 10v or less by the time it has run the length of the OEM loom, with 20 years of deterioration, minus the draw created by the starter solenoid/motor.

A couple of years ago I bought a gsx 600f 1992, and did a coil wiring mod/direct battery to relay/relay to coils. Its fired every morning since, hot or cold winter. I also pared back the HT leads an inch each and fitted new plugs so no claims to offer a solution. I'm just about to do the same work to my new to me 1996 Bandit 12.

Suzuki wiring problems (rolleyes)

Bypass the loom/startercurrent draw/deteriorated connections on the OEM loom.

Get a 5 pin automotive relay, hook up direct to battery (positive), insert a 10 Amp fuse, ground earth pin on the relay to frame using same bolt to mount relay in a convenient hole somewhere near. ( IIRC) Take the two orange wires off coils and use one on the switch connector pin on the relay, and connect two wires from pins 87 to the coils where the orange wires came from.

If that does not fix it, it has to be fueling related, or again back to the CDI.

Wiring used should be 15 amp guage or heavier, and all parts shouldn't run you more than 50 to 60 bucks if you hunt TM etc rather than repco or supercheap.

I did think that myself, but I completely rewired all the CDI connectors for power and from / too the coils so I really doubt thats the problem..

Ironically this is the first Suzuki i've had wiring issues with, though Ive heard horror stories..