Quick and simple ground test

[saddlebum]

As always there are a lot of electrical issues coming up in these forums maney of which are ground related. Most go through a lot of agravation checking there grounds only to find out there is nothing wrong with the ground. True you should always eliminate any possible ground faults as a first step in diagnosing electrical issues. so here is a very useful and simple test to verify your ground condition.

what you need

a voltmeter

a high beam headlight

two 3 ft lengths of wire

two aligator clips

A) connect an alligator clip to one end of each wire

B) connect the other end of each wire to a terminal on the high beam headlight

 

1) connect voltmeter to battery and record the voltage reading eg: 12V

2) connect the alligator clips from the high beam to the batt and record the resulting reading eg: 11.5 V the difference is your voltage drop eg: 0.5 v

3) disconnect the high beam aligator clip and the volt meter test lead from the neg post of the battery only

4) connect the volt meter neg lead to the engine block and read record the voltage reading eg: 12v

5) connect the alligator clip from the high beam to the same point on the engine block and not the voltage eg: 1) 11.2 v voltage drpo is relitivily close to that recorded in step (2) your ground to the engine is good you need not look any further. If for example your voltage upon connecting the high beam dropped to say for eg: 7v than you have a ground issue and need to locate it

6) repeat steps (4 & 5) but connect to the frame of the bike to test if the frame has a proper or faulty ground.

 

this test takes only several minutes to perform and is far more reliable than using an ohmeter because an ohmeter does not load up the circuit which would pass under a light currant load but fail under a heavy load.

 

slight modifications of this test can be used to load test any wire on the bike and will instantly reveal if a wire or circuit is sound or faulty with out having to tear the whole bike down eleminating a lot of unecessary work.

 

By leaving the voltmeter and head light connected to the neg side of the battery and moveing the positive side connections in the same maner the positve side of you electrical system can also be tested you must take more care however when loading up the positve side of the electrical system to be sure you don't accidently load up a sensitive component in the sysem by mistake. In such case i often disconnect both ends of the circuit apply voltage to one end of the wire and connect my voltmeter and then my test load to the other end.

Edited May 19, 2009 by saddlebum

[cowpuc]

Good stuff here,,, the comment about why an ohm meter doesnt work is spot on! Without a load on the device it is next to impossible to find the resistance to current flow because digital stuff is sooooooo sensitive.. Yea, listen to the guy that wrote this, he has talent!

[saddlebum]

Another simple and quick test is to use an automotive test light. Connect as though you were running a bypass wire if the circuit being tested is good the light will NOT light up. On the other hand if the cicuit is bad or has a weak point the light will glow. the weaker the ciciut the brighter the bulb will glow because it is trying to help out. You can also use this metod to check suspect points in the cicuit by using the test light to bridge the suspect fault here again if the light glows when you load the cicuit the piont between the two ends of the test light is bad or dirty. again this eliminates a lot of time and unnecessary tear down

[GeorgeS]

However, in a 12V circuit that is carrying " High Current " ( The charging circuit ) from the Stator, to the Rectifyer/Regulator unit, and Regulator to the Battery. Which is carrying 30 Amps or more !!.

 

Remember this, 1/2 or maby as high as 90 percent of the Individual Strands of wire that make up the #14 wire ( two of them, in parallel ) might be Corroded, or broken off inside the Crimped On Studs. ( at wire ends ) So, maby, only a small percent of the Strands may be makeing good contact. !! Now your #14 wire is only a #20 wire !!!

 

So--- Every Test you can think of useing an OHM meter will tell you that the Circuit is " Good " !!!

 

---- And it is, for the Extremly Small amount of current the Meter is pumping thru the circuit

 

BUT, try to pump 30 amps thru the circuit, now it gets HOT, and the Resistance will Rise, and you will be consumeing POWER, thru the Wire's, AT the Degraded Connection point--

 

Caused by either, Broken strands of the wire, Loose Crimps, Improper crimps, or even corrosiion on male and femal pins. These conditions cause HIGH RESISTANCE, and that is equal to a Heating Element.

 

When current flows thru the EXTRA Resistance, There is a Voltage Drop, and Power is consumed. ( none left to charge the battery )

 

Only way to find these items in the Charging Circuit, is to PHYSICALLY INSPECT THE CONNection POINTS !!! And as long as your doing it, RESOLDER them !!!

 

Of all the vehicals I have worked on over the years, Yamaha has about the worst quality of Wireing, plugs, and connections I have ever encountered !!! When it comes to the Charging system.

 

Put it this way. If you have a 1st Gen, and expect to keep it on the Road, the entire Charging system, Wiring lash up, should be Re-Built !!!

 

Especially the 2 blacks, and 2 Reds, From the Regulator, to the Battery.

 

And the 3 phase plug from Stator, to Regulator, Cut it out, and solder those 3 wires together. That Plug, is a PIECE OF JUNK !!!!!

[saddlebum]

Remember this, 1/2 or maby as high as 90 percent of the Individual Strands of wire that make up the #14 wire ( two of them, in parallel ) might be Corroded, or broken off inside the Crimped On Studs. ( at wire ends ) So, maby, only a small percent of the Strands may be makeing good contact. !! Now your #14 wire is only a #20 wire !!!

 

So--- Every Test you can think of useing an OHM meter will tell you that the Circuit is " Good " !!!

 

---- And it is, for the Extremly Small amount of current the Meter is pumping thru the circuit

 

BUT, try to pump 30 amps thru the circuit, now it gets HOT, and the Resistance will Rise, and you will be consumeing POWER, thru the Wire's, AT the Degraded Connection point--

 

Caused by either, Broken strands of the wire, Loose Crimps, Improper crimps, or even corrosiion on male and femal pins. These conditions cause HIGH RESISTANCE, and that is equal to a Heating Element.

 

When current flows thru the EXTRA Resistance, There is a Voltage Drop, and Power is consumed. ( none left to charge the battery )

 

Only way to find these items in the Charging Circuit, is to PHYSICALLY INSPECT THE CONNection POINTS !!! And as long as your doing it, RESOLDER them !!! !!!!

 

 

This is why I use the abve test using a high beam to load the cicuit. If only one or two strands in the wire are good they will easly carry the 12volts under a light load but load it up with the high beam connected along with the voltmeter and the voltage shown in a bad or weak circuit will drop drasticaly bcause of the thinned out wire, and or bad, loose or dirty connections cannot pass enough currant to maintain 12volts causing a voltage drop thus failing the test (think of a garden hose being pinched in the middle) If it passes this test you can be assurd all your connectios are good. there is no reason to tear the circuit apart and look for a fault that this test indicates is not there. and if the circuit fails this test well grab a case of beer sit down and get to work and start looking for the fault. With some variations to your hookup you can even narrow down to were you should start looking for the point of fault. I have used the test for thirty years working on trucks and trailers it has never failed me and has saved me hours of of unnessary work because if the test part or parts pass this test you need not waste time looking for something that is not there and can quickly move on to the next step. And this were an ohmeter falls short because it does not load the circuit being tested. An ohmeter for example will tell you a battery cable with one strand remaing or a coorroded terminal is good when its not, while the test I described will find it instantly and fail that cable. EG: I have seen wires turned to green powder pass enough currant for an ohmeter to pass it. a volt meter will shoow 12volts until you connect the high beam along side the volt meter and suddenly the volt meter drops to zero volts or even 1-2 volts because the wire or connection cannot now carry the increased load. you now know you have a problem and roughly were it is to be found.

Edited May 19, 2009 by saddlebum

[GeorgeS]

I'm just trying to explain it in simpler terms for the folks who are Electrically challanged.

 

There are not really that many connections in the charging section. and In less then 1/2 hour they can all be physically looked at, and repaired if needed.

 

If I were to buy a pre 90 1st gen tomorrow, the first thing I would do is Check every point in the charging system, by inspection. And add some extra grounding wires. And ReSolder the Battery cable studs. And install the upgraded stator, if needed or not, and the Dry Cell Battery, and cut out the STator Plug, and splice it.

 

Also, add an extra ground connection to the output plug of the Regulator.

 

And of course, check the 3 phase voltage output of the stator.

 

My bike has had just about every problem, in the charging system, you have ever read about for these bikes.

 

After about 8 years of putting up with the Slow Cranking, hard starting, I finally got it all modified. 2 odyessy batteries,( switched ) 2 solinoieds in parrallel, new #4 cables, all new ATM type fuse blocks,

 

Also, there are 7 item's powered from the Ignition Fuse. I removed 4 of those, and added seperate fuse's for those items.

 

I know, its all overkill, but mine works good now!! One touch of the button, and engine is running.

 

And, besides that Darn!! ITS RAINIG AGAIN IN SEATTLE :bang head:

[saddlebum]

Me thinks Between us George we have given enough food for thought in this thread alone which should help with most electrical issues.