Ignitor smokes then main 30a fuse blows

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Masika
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Re: Ignitor smokes then main 30a fuse blows

Postby Masika » Tue Jun 18, 2013 4:21 pm

Sorry i havnt replied, ive been waiting out schooldageek as he is coming to help me sort out the problem first hand. ive gone through 3 sets of cdis trying to figure this out. on the first 2 sets the cdis got extremely hot melting the goo and even blowing solder out one of the times and blowing the main fuse. on the 3rd time the both cdis quit not getting as hot just warm and the main fuse turned white like it wanted to blow but didnt. as these are slow blowing correct?

SchoolDaGeek
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Re: Ignitor smokes then main 30a fuse blows

Postby SchoolDaGeek » Tue Jun 18, 2013 6:25 pm

Volker_P wrote:
Just to track the facts precisely:

The bike will start with the bike battery. Chaging is deactivated (probably RRR plug pulled?). It will start and run for a while but as soon as you exceed 4000rpm it will kill both ignitors simultaneously and also blow the 30A fuse?

Are these details correct or did I mix up something?

Did you observe if the engine was still turning when the fuse blew or did it blow at a later time?


To my understanding that is the concise description of the problem. Without observation, I have always understood that it was a simultaneous meltdown, with the bike immediately dying, like sizzle sizzle pop. I am heading out there tomorrow, but if you catch this tonite, I would appreciate your line of thinking...
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SchoolDaGeek
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Re: Ignitor smokes then main 30a fuse blows

Postby SchoolDaGeek » Tue Jun 18, 2013 6:58 pm

Masika wrote: on the 3rd time the both cdis quit not getting as hot just warm and the main fuse turned white like it wanted to blow but didnt. as these are slow blowing correct?


Masika, for a primer on fuses, you can check wikipedia:

http://en.wikipedia.org/wiki/Fuse_%28electrical%29

Specifically when the bike was manufactured, the fuse box between the handlebars had 4 - 10amp fuses from the factory, by design, with the one 30amp tin strip fuse to run the whole system.

As you can see by the article, slow-blow fuses are specifically explained in the "Speed" section:

"A standard fuse may require twice its rated current to open in one second, a fast-blow fuse may require twice its rated current to blow in 0.1 seconds, and a slow-blow fuse may require twice its rated current for tens of seconds to blow."

Now this is just an example, but just through basic math, if the lighting, control, and instrument section of the bike compromises 4 seperate 10 amp circuits, and the starter motor portion of the bike is on that 30 amp circuit that also has to make sure the indicator lights and headlight/tail light work, you can rest assured the 30 amp tin strip is most certainly a slow blow fuse.

That is why I suggested that if you were going to modernize the bike, I would definitely NOT use a small 30Amp ATO blade fuse for that, but a Maxi-Fuse.

On top of that I have read that the fuse box bewteen the handlebars can accept 15 amp fuses with no problem to the 30 amp because they will still blow faster in their own isolated circuit than the 30 amp will. So a 30 amp fuse in this respect is supporting a system having 60 amps possible in the fuse box (not really because then the 30 amp would blow) but the point is with circuit breakers in a house for example, you can have a main breaker of 100, 125, or 200 amps, and have the sum of the the minor circuits in the box exceed that number without risk of fire or anything else. If you overload your dishwasher circuit, the dishwasher will shut off, it is a redundant check and balance system. If you really have everything running in the house all at once, A/C, Electric Dryer, Oven, Dishwasher, and taking a hot shower, then yeah, the main circuit might trip leaving you all soapy in the dark with dirty dishes and damp clothes.

The point to all of this is that a short is a short, somewhere, until the wire is burned through and no longer touching or a fire has started. Indicator lamps on your dash and the switches that activate them do not require a full 10 amps to operate, the fast blow 10 amp there is for safety in case of a short. Engineers do not place fuses in circuits at their maximum limit when brand new, they leave room by design, so that other components can fail first, that is why for example the turn signal relay is on a separate 10 amp circuit than the lightbulbs themselves, so that if your lightbulbs turn on, but just do not blink, you can see if it is the relay that failed, or the fuse to the relay, etc.

That is covered in the "Coordination of Fuses in Series" section.
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Volker_P
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Re: Ignitor smokes then main 30a fuse blows

Postby Volker_P » Wed Jun 19, 2013 1:27 am

The ignition is the only part of the electric circuit without a "handlebar fuse".
As ignitors melt and main fuse blows even without charging, the problem seems restricted to the ignition circuit behind the main fuse.

Having a look at the wiring diagram again, I have some thoughts on the black/white cables to ignition coils as well as to ignitors/CDI's.
This is the power supply for both, CDI's and coils. If the coil or CDI part (behind the split of cables) would be weak or interrupted, there would be an untypical potential difference at the CDI's.
As they contain semiconductors one does not really know what they do but it is known semiconductors at undefined input could do strange things.

A white fuse means surface oxidation due to heat. This is a hint it has been very close to failure.
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SchoolDaGeek
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Re: Ignitor smokes then main 30a fuse blows

Postby SchoolDaGeek » Thu Jun 20, 2013 9:05 pm

Does anyone know what the single rectifier does located near the two ignition coils? I see by the various schematics that it is between the neutral switch and the clutch switch, but should it only conduct 12v in one direction? Maskias conducted 12v in both directions so I removed it, the noticeable difference of the failure is that on the freeway/highway when you are upshifting, or anytime you pull the clutch in the neutral light is activated, but I am wondering if that is throwing 12v back at the solenoid where the 30amp fuse is located, meaning every stop light, you are causing a short of some kind. What does the "Silicon Rectifier" do, made by Stanley with only two pins near the two ignition coils?
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Volker_P
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Re: Ignitor smokes then main 30a fuse blows

Postby Volker_P » Fri Jun 21, 2013 12:55 am

SchoolDaGeek wrote:..., but should it only conduct 12v in one direction?

Yes it should. This is the typical application of a rectifier/diode like that.
In this case it serves to decouple the neutral lamp from the clutch switch as you already observed. Should have no further effect.

It would however be strange if this diode failed due to overcurrent as its typical loads are only the starter solenoid and the neutral bulb.

Possibly a hint to a ground issue.
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Masika
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Re: Ignitor smokes then main 30a fuse blows

Postby Masika » Fri Jun 21, 2013 1:15 pm

can a bad battery make it look like that R&R is bad? R&R showing over 15v at 3k RPMs swapped it out with another R&R (used) it also is giving me over 15v at 3k RPMs

SchoolDaGeek
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Re: Ignitor smokes then main 30a fuse blows

Postby SchoolDaGeek » Sun Jun 23, 2013 10:45 am

Volker_P wrote:
SchoolDaGeek wrote:..., but should it only conduct 12v in one direction?

Yes it should. This is the typical application of a rectifier/diode like that.
In this case it serves to decouple the neutral lamp from the clutch switch as you already observed. Should have no further effect.

It would however be strange if this diode failed due to overcurrent as its typical loads are only the starter solenoid and the neutral bulb.

Possibly a hint to a ground issue.


Hey Volker, in my experience, a regular diode only passes .7 volts in the forward direction but has a breakthrough voltage which effectively ruins the diode when the reverse breakthough voltage is exceeded.

The dash Neutral indicator lightbulb, being 12v would need what voltage then to light? I remember from my old electronic kits that voltage is somewhat relevant to current, etc. But would the bulb need an parallel array of diodes to pass 1.4 volts (say two in parallel) or 17 to reach 12v?

I am just wondering how this "Stanley" is made for $19 OEM. If it has a breakthrough voltage of 16v or so, it possibly could have been ruined during the short.

The problem I diagnosed after stripping down the entire wiring harness and giving it a good inspection inside, then re-wrapping it with 350 degree harness tape is that when the original ignitors started melting, they dripped their black goo right into the starter solenoid plug. It was a literal mess, took most of the day to disassemble, clean it, and re-wrap it with heat shrink this time around the plastic connector so any further goo in the future would go AROUND the connector instead of into the spade connector spaces. I believe this was the cause of the short since the Red/white and Red wires had so much gunk inside I would be surprised if they were even functioning at 50% of their AWG.

The other item I found was a neglected choke cable that would send the bike into the 5000rpm range at startup, overchoke, and kill the motor. With the R/R sending north of 16v at this speed, reduced AWG in the solenoid connectors, it is no wonder to me that the bike would not stay alive and fried a few ignitor modules. We refilled the last good set with the JB Weld, I put a cardboard backing on them and wrapped them in the hi-temp harness tape so they could be used immediately and dry later, and the bike started fine with a lubricated choke cable and a few modulations to the main idle screw knob.

The bike is running now without burning up the ignitors, they have JB weld in them so they will no longer melt, the solenoid connection is shrink wrapped so no more contaminants can get in, the entire harness has been checked, and cleaned, the igntion switch tested at only .1 ohm and the run/stop and starter button were dismantled and cleaned to a bright shine.

Upon putting everything back on the bike is when I tested the Stanley rectifier, found that it conducted electricity in both directions and so removed it.

As of this post, there are three parts that still need replaced, the Stanley rectifier, the R/R for charging, and the headlight because of the burned out low beam (another indication of 16+ volts)
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Volker_P
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Re: Ignitor smokes then main 30a fuse blows

Postby Volker_P » Tue Jun 25, 2013 1:49 am

The black cable from the RR to the ignition switch is the reference for the RR. If there is an enhanced resistance (possibly only occuring at real current), the charging voltage will increase considerably.

You already cleaned out the ignition switch, but it seems there is still a problem like that.

I would also check the second red/white charging cable from the RR to the starter solenoid with the main fuse. Possibly the tool short incident had an impct here. At least check out the cables and contacts in the plug of the starter solenoid.
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SchoolDaGeek
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Re: Ignitor smokes then main 30a fuse blows

Postby SchoolDaGeek » Fri Jun 28, 2013 9:08 pm

Ignition switch tested fine, solid clicks, and only .1 ohm.

Masika still had problems after the initial ride and found the white rotor brush wire was shorting to the case (we simply ran out of time at 11 p.m.) and also found a broken main wire near the coils that I missed because the rubber jacket was still intact. It was broken but did not pierce the jacket of the individual wire, this came about over the 34 year lifetime of the bike.

I had unwrapped the entire harness off the bike and looked for anything at all but it was so subtle I missed it. Once rewrapped with new harness tape and put back on the bike, the new tightness and slightly off placement aggravated the break so anytime the handlebars were turned to the right the extra stretching would kill the bike. This ended up being the only way the break was found because it was not externally visible on the wire. Masika got a lesson on a bike 10 years his senior, that is for sure!

So you were right Volker, it was more or less right at where the steering neck bends the harness.

At least the ignitors survived. All is well again.
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Volker_P
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Re: Ignitor smokes then main 30a fuse blows

Postby Volker_P » Tue Jul 02, 2013 1:55 am

Good to hear you found the issues.
This electric stuff can be quite annoying over a long time.
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