lost spark?
#21
09-12-2023, 03:17 AM
You'll have power on both terminals of coils because it's ground-switched circuit. When switch is open, there's no current flow and no voltage-drop. In this circuit, input and output terminals of bulb is exactly same as battery-voltage:
When switch is closed, then current flows and voltage on ground side of circuit drops to zero (supply side still at battery-voltage). Can only see that action with oscilloscope as grounding interval of spark-unit too short to measure with anything else.
Can also use solenoid-light to check for grounding-pulses from spark-unit. It has duration-extending circuity to keep light lit long enough for human eyes to see. Not as useful as oscilloscope, but very handy tool. https://www.amazon.com/dp/B0028QGU6C/
Hopefully you didn't make any alterations to circuits & wiring due to low battery. If you've replaced any parts, put ALL original parts back on bike. DON'T do ANYTHING else until battery is at least 13.5v and does not drop below 12v when cranking.
When switch is closed, then current flows and voltage on ground side of circuit drops to zero (supply side still at battery-voltage). Can only see that action with oscilloscope as grounding interval of spark-unit too short to measure with anything else.
Can also use solenoid-light to check for grounding-pulses from spark-unit. It has duration-extending circuity to keep light lit long enough for human eyes to see. Not as useful as oscilloscope, but very handy tool. https://www.amazon.com/dp/B0028QGU6C/
Hopefully you didn't make any alterations to circuits & wiring due to low battery. If you've replaced any parts, put ALL original parts back on bike. DON'T do ANYTHING else until battery is at least 13.5v and does not drop below 12v when cranking.
#22
09-14-2023, 11:28 PM
You'll have power on both terminals of coils because it's ground-switched circuit. When switch is open, there's no current flow and no voltage-drop. In this circuit, input and output terminals of bulb is exactly same as battery-voltage:
When switch is closed, then current flows and voltage on ground side of circuit drops to zero (supply side still at battery-voltage). Can only see that action with oscilloscope as grounding interval of spark-unit too short to measure with anything else.
Can also use solenoid-light to check for grounding-pulses from spark-unit. It has duration-extending circuity to keep light lit long enough for human eyes to see. Not as useful as oscilloscope, but very handy tool. https://www.amazon.com/dp/B0028QGU6C/
Hopefully you didn't make any alterations to circuits & wiring due to low battery. If you've replaced any parts, put ALL original parts back on bike. DON'T do ANYTHING else until battery is at least 13.5v and does not drop below 12v when cranking.
When switch is closed, then current flows and voltage on ground side of circuit drops to zero (supply side still at battery-voltage). Can only see that action with oscilloscope as grounding interval of spark-unit too short to measure with anything else.
Can also use solenoid-light to check for grounding-pulses from spark-unit. It has duration-extending circuity to keep light lit long enough for human eyes to see. Not as useful as oscilloscope, but very handy tool. https://www.amazon.com/dp/B0028QGU6C/
Hopefully you didn't make any alterations to circuits & wiring due to low battery. If you've replaced any parts, put ALL original parts back on bike. DON'T do ANYTHING else until battery is at least 13.5v and does not drop below 12v when cranking.
The following users liked this post:
dannoxyz (09-16-2023)
#23
09-15-2023, 12:30 AM
Senior Member
Ok, you're on track with ignition-coils. Just need to find some that's within spec. Should
bench-test them 1st to make sure they work.
Once you've got more than 11v powering spark-unit when cranking, it should be functional. Connect 'noid light to both terminals of each coil and verify it blinks, showing triggering signals are coming from spark-unit. If not, yeah it may really be bad.
Be careful about used units. 1987 had some bad ones. Seems to have fixed by 1988 and there's no reports of them going bad. But they have same part#, so might not know which year you're getting.
Good luck!
bench-test them 1st to make sure they work.
Once you've got more than 11v powering spark-unit when cranking, it should be functional. Connect 'noid light to both terminals of each coil and verify it blinks, showing triggering signals are coming from spark-unit. If not, yeah it may really be bad.
Be careful about used units. 1987 had some bad ones. Seems to have fixed by 1988 and there's no reports of them going bad. But they have same part#, so might not know which year you're getting.
Good luck!
#24
09-15-2023, 02:51 AM
Ok, you're on track with ignition-coils. Just need to find some that's within spec. Should
bench-test them 1st to make sure they work.
Once you've got more than 11v powering spark-unit when cranking, it should be functional. Connect 'noid light to both terminals of each coil and verify it blinks, showing triggering signals are coming from spark-unit. If not, yeah it may really be bad.
Be careful about used units. 1987 had some bad ones. Seems to have fixed by 1988 and there's no reports of them going bad. But they have same part#, so might not know which year you're getting.
Good luck!
bench-test them 1st to make sure they work.
Once you've got more than 11v powering spark-unit when cranking, it should be functional. Connect 'noid light to both terminals of each coil and verify it blinks, showing triggering signals are coming from spark-unit. If not, yeah it may really be bad.
Be careful about used units. 1987 had some bad ones. Seems to have fixed by 1988 and there's no reports of them going bad. But they have same part#, so might not know which year you're getting.
Good luck!
#25
09-15-2023, 11:17 AM
Senior Member
You're most welcome!
Bench test coils by themselves. Otherwise bad wiring may prevent good ones from firing. You'd never know they were good.
NO!!! Don't fry battery with auto-charger! Up to 1a max with multi-stage smart-charger. Desulfate mode really revives old batteries.
Use Deoxit to clean corrosion off terminals.
Want to get to where with key ON/kill=RUN, you pretty much get same voltage at coils as from battery. Damn Honda and their low-spec wiring with unsealed connectors bare-brass terminals that corrode! Causes all sorts of problems with power circuits.
Bench test coils by themselves. Otherwise bad wiring may prevent good ones from firing. You'd never know they were good.
NO!!! Don't fry battery with auto-charger! Up to 1a max with multi-stage smart-charger. Desulfate mode really revives old batteries.
Use Deoxit to clean corrosion off terminals.
Want to get to where with key ON/kill=RUN, you pretty much get same voltage at coils as from battery. Damn Honda and their low-spec wiring with unsealed connectors bare-brass terminals that corrode! Causes all sorts of problems with power circuits.
Last edited by dannoxyz; 09-15-2023 at 11:23 AM.
#26
09-15-2023, 11:33 AM
You're most welcome!
Bench test coils by themselves. Otherwise bad wiring may prevent good ones from firing. You'd never know they were good.
NO!!! Don't fry battery with auto-charger! Up to 1a max with multi-stage smart-charger. Desulfate mode really revives old batteries.
https://www.amazon.com/NOCO-GENIUS1-...dp/B07W46BX31/
Use Deoxit to clean corrosion off terminals.
https://www.amazon.com/DeoxITLiquid-...dp/B0015A5AAY/
Want to get to where with key ON/kill=RUN, you pretty much get same voltage at coils as from battery.
Bench test coils by themselves. Otherwise bad wiring may prevent good ones from firing. You'd never know they were good.
NO!!! Don't fry battery with auto-charger! Up to 1a max with multi-stage smart-charger. Desulfate mode really revives old batteries.
https://www.amazon.com/NOCO-GENIUS1-...dp/B07W46BX31/
Use Deoxit to clean corrosion off terminals.
https://www.amazon.com/DeoxITLiquid-...dp/B0015A5AAY/
Want to get to where with key ON/kill=RUN, you pretty much get same voltage at coils as from battery.
#27
09-15-2023, 12:12 PM
Senior Member
Sending 10a through battery would fry and destroy it. With lead-acid, you want to charge at 1/10th of capacity, or 1.4a max in this case. Even better is multi-mode charging with desulfation phase 1st. Then pulse-charging, maintenance and long-term storage modes really alleviates having to worry about battery.
Bench test coils by making them spark. Use spare battery or charger as power supply.
1. connect plug wire to coil and insert plug at other end
2. ground case of spark plug to -neg terminal of battery
3. connect alligator test-leads to each primary terminal of coil
4. connect one end of test-lead to +pos coil-terminal
5. with other test-lead end, repeatedly tap and release from -neg battery-terminal
Do you see bright-blue spark at plug???
Bench test coils by making them spark. Use spare battery or charger as power supply.
1. connect plug wire to coil and insert plug at other end
2. ground case of spark plug to -neg terminal of battery
3. connect alligator test-leads to each primary terminal of coil
4. connect one end of test-lead to +pos coil-terminal
5. with other test-lead end, repeatedly tap and release from -neg battery-terminal
Do you see bright-blue spark at plug???
Last edited by dannoxyz; 09-16-2023 at 03:42 AM.
#28
09-15-2023, 12:18 PM
Sending 10a through battery would fry and destroy it. With lead-acid, you want to charge at 1/10th of capacity, or 1.4a max in this case. Even better is multi-mode charging with desulfation phase 1st. Then pulse-charging, maintenance and long-term storage modes really alleviates having to worry about battery.
Bench test coils by making them spark:
1. connect plug wire to coil and insert plug at other end
2. connect alligator test-leads to each primary terminal of coil
3. connect one end of test-lead to +pos coil-terminal
4. with other test-lead end, repeatedly tap and release from -neg coil-terminal
Do you see bright-blue spark at plug???
Bench test coils by making them spark:
1. connect plug wire to coil and insert plug at other end
2. connect alligator test-leads to each primary terminal of coil
3. connect one end of test-lead to +pos coil-terminal
4. with other test-lead end, repeatedly tap and release from -neg coil-terminal
Do you see bright-blue spark at plug???
Ok cool , I'll try that ... I didn't know that could be done , Thanks a ton and I'll let You know what happens !! 😁
The following users liked this post:
dannoxyz (09-16-2023)
#30
09-16-2023, 01:53 PM
sorry, i left out step of grounding case of plug. Please review procedure above.
https://www.youtube.com/watch?v=oc941J0wh0Y
https://www.youtube.com/watch?v=oc941J0wh0Y