Work Case #21 DRZ400 in 2019
Sort of a Work Case, but, well, it's worth a share. So, it's 2019 and three years after leaving the job I get a phone call from my old boss: "Hi Steve how's it going? Have I got a deal for you!"
It was a DRZ they were taking in part exchange. Of course, there was a catch, the bike had an electrical problem and wouldn’t start, so a low price agreed so even if the coils and whole ignition system needed replacing I would still have a good buy.
When the bike was dropped off I was quite happy - it was cosmetically very tidy, was the proper DRZ colour of yellow(!) and a 2007 model - my newest bike for some time!! It did however have a lot of loose and cut wires where someone had tried, unsuccessfully, to fix it. So first job was to repair some of that, check for continuity and shorts, and basically start the fault-finding from scratch.
Much to my surprise the bike then fired up instantly, sounded very smooth and there was no smoke – great!
Ooops, spoke to soon, as it stopped dead.
A quick probe around with the multi-meter showed the main fuse had blown and there was a short to earth from the battery positive. OK….so I start checking over the wiring, and after a few minutes the short disappeared!
Oh great one of those....
The wiring was all in good condition so I try wriggling and bending every bit with no luck, so re-start the bike and it would run for 20 seconds and then die again, the short coming back.
Hmm, tricky! So I disconnect everything apart from the bare minimum to run the engine, i.e. the CDI and coil, start it up - it runs for a few seconds and dies again.
Whaaaaatt??
OK so study the circuit diagram to see what else is on the positive circuit, but it turns out I have already disconnected everything connected to 12V.
Well, apart from the CDI. Oh?
Of course the short has now gone again, so start the bike, again, and as soon as it stops I quickly check the positive line going to the CDI, and yes it is that! – the CDI has an internal short!
OK, unusual, and not ideal, but at least the fault is now found, and, as it happens I have another bike being broken for spares so a replacement CDI is already to hand. So fit that and the bike starts up and stays running, sweet as a nut – fantastic!
Now, the story should be over at this point, but having an electronics background I like to have a good probe around with the meter to check the generator ac, rectifier, and battery are all ok, Starting at the @rse end, I pop the meter on the battery and holy sh!t! - I quickly stop the engine as the regulator is putting out over 17 volts!
Which more than likely cooked the CDI and was about to wreck the replacement too! But fortunately I switched off in time.
The pic shows bike is all sorted now, but.... there is part 2 to of this to come as it turned out this story of electric problems was, um, not actually over
Work Case #21 DRZ400 in 2019 + Fun 'n Games in 2020
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Work Case #21 DRZ400 in 2019 + Fun 'n Games in 2020
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Last edited by Thedktor on Sun Jan 10, 2021 8:55 am, edited 1 time in total.
- Steve
Southampton area
DR350, 349, DRZ, 701
Southampton area
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- chunky butt
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Re: Work Case #21 DRZ400 in 2019
I'm in, I'll get a cuppa ready for part to.
And now, Harry, let us step out into the night and pursue that flighty temptress, adventure.
Suzuki DR200 Djebel.
Suzuki DR200 Djebel.
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Re: Work Case #21 DRZ400 in 2019
Excellent.
You have a very clear and interesting way of telling this. Look forward to more.
You have a very clear and interesting way of telling this. Look forward to more.
Greyhound Racing .... don't bet, don't go - you bet, they die
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Re: Work Case #21 DRZ400 in 2019
Electrics, eeeeeeeesh We have plenty of those in the Ducati shop where I work
Looking forward to part 2.
Looking forward to part 2.
one-legged adventurer
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Re: Work Case #21 DRZ400 in 2019
So to recap, the regulator had failed and was putting out far too much voltage, so an old DR350 rectifier/regulator was temporarily wired in just for testing. A quick spin up the road confirmed that the bike was in great shape mechanically and ran faultlessly – phew, so I hadn’t bought a pile of junk!
The bad regulator was not an OEM one and of unknown origin, so had presumably failed cos it was cheap. It was unlikely that the generator had killed it - unlike the more sophisticated alternators fitted to cars, smaller motorcycles use a simple, passive coil 3-phase generator and can’t magically produce more volts and current than originally designed for, only less if they go wrong. If the output was spikey and not a clean wave it could I suppose shorten the life of the rectifier/regulator.
Anyway, easy enough to test and two of the phases were putting out a nice steady 60-70V ac, but the third was lower and erratic, so an easy decision made to replace the stator/coils for reliability sake.
Well, I’m glad I did!
Some numpty had obviously replaced the stator previously and left this wire for the pick-up coil to rub against the flywheel! Genius, I mean it only spins at up to 10,000 rpm - it will be fine…
This is my correctly installed one, no wires exposed.
So with the replacement stator, rectifier/regulator and CDI fitted, the next test ride went all of 200 yards to the end of my road when the bloody bike conked out again! What the actual F….. ?!
Push the bike back to base and after a short time discover the kill switch is incredibly sensitive, just a brush against it would kill the engine and then it would stick internally unless prodded several times. So I prodded it several times and all has been fine since!
(Tank borrowed off the blue one temporarily)
The bike has been in regular use for the last year and runs perfectly, but I did nearly kill it at one point, so will add that story next....
The bad regulator was not an OEM one and of unknown origin, so had presumably failed cos it was cheap. It was unlikely that the generator had killed it - unlike the more sophisticated alternators fitted to cars, smaller motorcycles use a simple, passive coil 3-phase generator and can’t magically produce more volts and current than originally designed for, only less if they go wrong. If the output was spikey and not a clean wave it could I suppose shorten the life of the rectifier/regulator.
Anyway, easy enough to test and two of the phases were putting out a nice steady 60-70V ac, but the third was lower and erratic, so an easy decision made to replace the stator/coils for reliability sake.
Well, I’m glad I did!
Some numpty had obviously replaced the stator previously and left this wire for the pick-up coil to rub against the flywheel! Genius, I mean it only spins at up to 10,000 rpm - it will be fine…
This is my correctly installed one, no wires exposed.
So with the replacement stator, rectifier/regulator and CDI fitted, the next test ride went all of 200 yards to the end of my road when the bloody bike conked out again! What the actual F….. ?!
Push the bike back to base and after a short time discover the kill switch is incredibly sensitive, just a brush against it would kill the engine and then it would stick internally unless prodded several times. So I prodded it several times and all has been fine since!
(Tank borrowed off the blue one temporarily)
The bike has been in regular use for the last year and runs perfectly, but I did nearly kill it at one point, so will add that story next....
- Steve
Southampton area
DR350, 349, DRZ, 701
Southampton area
DR350, 349, DRZ, 701
- chunky butt
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