motorbike ignition fault
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- OneWave
- Posts: 15
- Joined: Sat Sep 29, 2012 11:14 am
- Location: watford, herts
motorbike ignition fault
hi peeps,
one of my wifes bikes (1998 suzuki bandit gsf1200) has had a bad running issue for a while now which has now got to the point of not even starting or running now.
i have only had my picoscope for 2 days and am really in at the deep-end!
previously we compression tested, valve clearences checked, new plugs, carbs stripped & cleaned - and new coils fitted (old ones from this bike fitted to another bike which ran perfectly - swapped back and same issues)
here is a trace i ran on the coils this morning - i can see that there is a problem, i just dont know how to read the traces - please could someone point out to me whats causing what?
(btw - the coils are wasted spark types, one coil for pots 1+4 & one coil for pots 2&3)
one of my wifes bikes (1998 suzuki bandit gsf1200) has had a bad running issue for a while now which has now got to the point of not even starting or running now.
i have only had my picoscope for 2 days and am really in at the deep-end!
previously we compression tested, valve clearences checked, new plugs, carbs stripped & cleaned - and new coils fitted (old ones from this bike fitted to another bike which ran perfectly - swapped back and same issues)
here is a trace i ran on the coils this morning - i can see that there is a problem, i just dont know how to read the traces - please could someone point out to me whats causing what?
(btw - the coils are wasted spark types, one coil for pots 1+4 & one coil for pots 2&3)
- Attachments
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- coil 2-3 bandit12.psdata
- (123.84 KiB) Downloaded 295 times
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- coil 1-4 bandit12.psdata
- (128.89 KiB) Downloaded 282 times
Re: motorbike ignition fault
tb
I'm no bike guru but you can't really diagnose an ignition problem by just the primary & secondary.
Can you take another capture using the amps clamp too so we can see the coil current ramp with primary & if you have another channel the secondary too ?
Put some more time on the screen to see more than one event & sample at an interval of 1µs.
Grab a CKP/CMP capture too while you're at it.
I'm no bike guru but you can't really diagnose an ignition problem by just the primary & secondary.
Can you take another capture using the amps clamp too so we can see the coil current ramp with primary & if you have another channel the secondary too ?
Put some more time on the screen to see more than one event & sample at an interval of 1µs.
Grab a CKP/CMP capture too while you're at it.
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- OneWave
- Posts: 15
- Joined: Sat Sep 29, 2012 11:14 am
- Location: watford, herts
Re: motorbike ignition fault
thanks for that - ill redo the tests tomorrow
i could only afford the 2 channel kit so ill just have primary current & voltage on one screen
*warning - daft question alert* whats a CKP/CMP capture?
i could only afford the 2 channel kit so ill just have primary current & voltage on one screen
*warning - daft question alert* whats a CKP/CMP capture?
Re: motorbike ignition fault
May pay to scope the crank signal, I've got a 600 and could scope that as I believe they use the same pick up.
Re: motorbike ignition fault
Grab a CKP/CMP capture too while you're at it.
May pay to scope the crank signal



Re: motorbike ignition fault
Sorry Rob, I skim read the post.
My bad
My bad

Re: motorbike ignition fault
Setting aside the pico files for a moment. You have pretty much covered all potential problems, excepting ignition control unit, and back pressure problems in the exhaust.
Are you actually getting a spark at the plugs? Take it you've changed plugs too?
Doubt you bike will have a camshaft position sensor - given it has got carbs not FI.
Any backfiring?
Are you actually getting a spark at the plugs? Take it you've changed plugs too?
Doubt you bike will have a camshaft position sensor - given it has got carbs not FI.
Any backfiring?
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- OneWave
- Posts: 15
- Joined: Sat Sep 29, 2012 11:14 am
- Location: watford, herts
Re: motorbike ignition fault
i am getting a weak spark - it only seems to be firing on one pot (no. 2), its the only downpipe that gets warm - the others are stone cold - which is very odd as i would of expected 2 pots to be trying to fire at least
its has new plugs and theres no backfiring
its has new plugs and theres no backfiring
Re: motorbike ignition fault
I missed you saying you had cleaned the carbs so ignore the CMP & grab coil current/primary/secondary/CKP, I don't suppose you have an adjustable spark tester ? Do you have a schematic of the system ? post it up let's have a look.
- Fat Freddy
- TwoWaves
- Posts: 317
- Joined: Fri May 04, 2012 4:52 am
Re: motorbike ignition fault
To me, it kind of looks like it's tracking to ground.
What colour are your plugs?
FF
What colour are your plugs?
FF