Dead bike

[Seeker]

Originally Posted by Bibio

not so.

everything is positive until it gets to the negative plates in the battery.

there is no such thing as a "ground or earth" on DC electrics. its either live or off.

Whilst you may be correct in your pedantic way. We tend to connect one side of the battery to the chassis and refer to that as ground. Assuming the negative side of the battery is bonded to the chassis most people refer to the vehicle as negative earth, any positive wire touching the chassis will cause a short.

So, assuming his SV is negative earth like most vehicles are these days, touching the black wire/white stripe (if it's a Suzuki harness wire) will not cause a short.

[simon1]

seeker...i did touch the wire and nothing happened?...…apart from the other possibilitys,fried wires etc...is there a good chance that the cdi would of fried....can they or is it highly unlikely?...

[glang]

Originally Posted by Bibio

there is no such thing as a "ground or earth" on DC electrics. its either live or off.

Not so.
A DC system can have a ground or earth if one of the supply terminals is connected to 'earth'. Some cars used to be positive earth and now are negative earth same as our SVs

[Bibio]

lets get it straight.... there is no fekin earth/ground on a vehicle.. if there is can you please tell me where its coming from as a battery or rectified DC has either positive or negative. what everyone calls a ground/earth on a vehicle is actually a COM (common).

its this magical ground/earth palaver that is confusing people as they are looking for this mythical thing when testing vehicle electrics. its not there its all positive and either on or off.

what people commonly refer to as positive or negative earth on a vehicle is actually the difference of the COM (common) connection point. it can be either negative (negative earth vehicle) positive (positive earth vehicle) but both are a common point in which power can either "flow or return". the difference is the frame on a positive earth vehicle is connected to the positive battery terminal so how can it be an earth/ground.......... same goes for a negative earth vehicle....

there is no ground/earth is a COMMON.

[glang]

I think theyre just different names for the same thing: ground, earth, return, common are all just paths for the electrons (AC or DC) to complete the loop. Sometimes theyre for normal use (as the frame of our bikes are for the starter motor return), in other cases just emergency use as in domestic 240v earth wires and then also the actual soil which is used for the high voltage return to power stations.

[Seeker]

Originally Posted by Bibio

lets get it straight.... there is no fekin earth/ground on a vehicle.. if there is can you please tell me where its coming from as a battery or rectified DC has either positive or negative. what everyone calls a ground/earth on a vehicle is actually a COM (common).

It's a frame of reference, you're just being pedantic. What next, arguing about electron flow versus conventional current flow through a diode or whether holes move in a bipolar junction transistor?

We use the expression so people know which way is up, it's a convention. You may not like it but it's a common industry nomenclature which is why when ordering parts for an old British bike you have to define whether it's positive or negative earth since they switched over in the 70s. I remember buying car radios and specifying pos or neg earth, it's not a new phenomenon. In your world you'd specify a "negative common" electronic ignition for example or would you say electronic ignition for a negative earth?

To hammer it home: "What everyone (except bibio) calls a ground/earth is a common". maybe you need to reevaluate your position

[DarrenSV650S]

Originally Posted by simon1

Does anyone know what this is...it is in the end of this connector..has a + on one blade and 0.2 on it....

Looks like the rectifier diode.


First thing to do is get a wiring diagram. Follow the lines from the battery positive on the drawing and check the various component points on the circuit that should be live. Looking for burned wires or connectors as you go.

[SV650rules]

Cars and other vehicles refer to the battery polarity connected to bodywork as ground or earth just to keep things simple ( ground normally used by Americans ) - cars used to be positive earth until the manufacturer's found that it cause corrosion of the bodywork, so they connected the battery negative to bodywork and prevented the corrosion. The term common is normally used in electronics and DC industrial wiring to identify the return because it probably will not be connected to earth or any metalwork for various reasons.

The fact that the negative battery terminal on cars and bikes is connected to the bodywork / frame means that the term earth or ground makes sense to vast majority of people.

There is also in electrical / electronic terms an important term wrt ( with respect to ) so although both ends of a load are positive compared to the battery or supply common ( of whatever polarity ) one end will be more positive (or negative) wrt the other end, for example the anode of a diode has to be positive wrt cathode by a certain voltage for current to flow, the other thing is potential ( voltage ) difference or pd, and it is pd that is used to calculate current flow in parts of a circuit.

High impedance voltmeters are great on electronics because they only very minimally affect the circuit being tested.

The problem using high impedance voltmeters to measure voltage on other things is that they draw minute amounts of current, and can measure a ' standing voltage' that will disappear as soon as any current is drawn, a good way to increase load drawn by a meter is to put a 12volt bulb across meter probes that will draw a current and you are then measuring the pd across a load that is passing current this will show up any extra resistance in the circuit outside your bulb as a lower than 12 volts across the bulb, as when current is being drawn any resistance in circuit will cause a voltage drop across it, which will show as a lower voltage across your bulb.

[simon1]

Thank you all for your help....I will report back with what the issue was ,when I find it!!!...….

[Seeker]

Originally Posted by simon1

Thank you all for your help....I will report back with what the issue was ,when I find it!!!...….

sorry we couldn't help. Your bike seems to have a few wiring modifcations judging by the splices seen in your pix which makes it nigh on impossible to troubleshoot remotely unless the new wires can be identified. Please do let us know what you find.