Step 7 on Expanded charging system guide

[bloglos]

I'll lay it out step by step and hopefully someone can tell me if I've missed something. For my 1980 with stock TCI.

Step 1: New fully charged battery.
Step 2: Slap test, nothing, nothing at all. Tried jumping green from rec/reg combo and again nothing on slap test.

Step 3: Bike warm up and brought up to 3000rpm, no charging at battery. Jumped green from regulator to ground, again no change in charging.

Step 4: Voltage on brown wire. Full voltage at positive brush with key on all the way back to key switch.

Step 5: Always had full voltage at brush but I checked again anyways, slap test fail, 3000rpm no charge. I pulled the brushes and tested Ohms between rings (5.1 Ohms, and infinite between rings and engine ground, which I believe is good. Brushes are an acceptable length.

Step 6: Each white wire, while connected, while idling was very very low, between all combinations, between .50-1.98 Ohms. This would indicate something is grounding my stator I believe, so onto step 7!

Step 7: I unplug each white connector, and at each combination I get 0.00 Ohms BUT when I put a lead to each white and a lead to ground, the I get an infinite reading, which I believe I am supposed to get? Also what is the stator lead pigtail I'm supposed to check?

I'm stumped at this point, could someone offer a suggestion?

 

[bloglos]

Ok, so I took the stator off and cleaned up the rings and the ohm readings between rings is 0.00 Ohms? Did I do something wrong? don't these things usually weaken ? or can they just fry like that?

 

[XSLeo]

Never do ohm readings with power on what your testing. It will damage your meter. Most often blowing the fuse in the meter.
Now with the bike idling you test AC voltage on the white wires. You should get 10 VAC or a bit more.
Step 2, You have battery voltage on the brown wire at the brush, ground the green wire and get no slap. How long are the brushes? The book calls for a 1/4 inch minimum, 3/8 is a better minimum. I might suggest replacing them if they are the originals. don't cost much and you can eliminate them as the problem.
Step 5, your 5.1 ohms on the slip rings, infinity from rings to ground, is right, good rotor.
Step 7, You unplug the big plug between the stator and harness, this lets you test the ohms between the three white wires. There is a yellow wire that goes into a single plug, unplug this yellow wire. Now number the three white wires, 1,2,3. Test ohms 1-2, 2-3 and 1-3. All these readings should be the same and be .9 ohms. Infinity from the wires to ground.
The yellow wire goes up to the safety relay and goes to ground through a winding in the relay. This winding has about 20 ohms. This can throw off your test readings by about 20 ohms.
On your meter use the lowest ohm setting when checking the rotor and stator. 200 ohms on digital meters. Before you do the actual test touch the meter probes together, this gives you the reading of just the meter leads. Remember this reading.
Now do the test, subtract the first reading from the second reading to get the actual ohms. One of my meters reads 1.2 ohms for just the leads. So when I check a low ohm reading And get a 6.5 ohm reading on a coil I have Subtract the 1.2 from the 6.5, 6.5-1.2 = 5.3 Well within spec. I have another meter that checks .1 on the leads. So if I got the same 6.5 reading, 6.5 - .1 is 6.4 Still ok but a bit high.
Also check inside your meter for a blown fuse. If blown you get no ohm readings.
Leo

 

[bloglos]

Thanks Leo, your message leads me to believe I've fried the fuse in my meter. First test gave a reading of 5.3 - .2 ohms = 5.1 ohms. After some fumbling around I probably wrecked the fuse as it no longer reads .2ohms when touching the leads together, just 0 no matter what I do..

My brushes are about .33" long, so a little short on the 3/8 minimum, but longer than the 1/4" minimum. I'm going to check the ohms at the rings again later today with my meter sorted out, and if it checks out I'll order some new brushes to start! I'll report back, thanks for advice.

 

[bloglos]

Looking at a set of brushes online leads me to believe the previous owner may have attempted to replace an old set of brushes with a salvaged set from an older stator. They look a lot like the ones from a pre 80 model. What affect would this have?

 

[weekendrider]

Too high a charge rate is one effect.

 

[bloglos]

Well that's definitely not my issue heh.

 

[bloglos]

Ok! So I did the test correctly this time on my rotor with three different multimeters and it's sitting at 4.7ohms. Which is certainly not optimal, but I would figure that this is still runnable? and certainly not the reason I'm not even charging a little bit.

I'm guessing since it's not magnetizing at all, that it's not getting power, and since I have full power at the stator connector, that maybe, perhaps new brushes are in order. I've ordered a set and have cleaned up the rings with some high grit paper and whiped them down, they look good.

I'll install the new brushes and check back. In the meantime, any advice is appreciated!

 

[XSLeo]

The 4.7 should get you something but it's on the way out.
On the 70-79 brushes one looks like the 80 up brushes, the other has a longer metal strap. It comes up from under one mount screw, over the top and down under a second mount screw then turns 90 degrees and goes under a third screw.
The 80 up brushes look the same and are interchangeable. On the 80 swapping them around to even out the wear makes them last longer.
I'll post some pics. First pic are the 70-79 brushes, second is the 80 up.
Leo

 

[gggGary]

I have one at 4.8 ohms and it's charging, I just got two of the racetech (on sale for $90) in the mail today, they ohmed out at 5.3 and 5.2 Quality looks reasonable, I will probably sand the face a bit before installing one. there is a bit of roughness at the copper phenolic interface. I will also do a "deck height" check vs the stock one when mounted. This has been an issue with some aftermarket rotors.

http://racetechelectric.com/c-701665-rotors-street-yamaha-rotors.html

But that's not your no slap issue I smell an issue with how your brushes are wired..... Picture of yours maybe?

 

[gggGary]

Your icon shows a bobber and the the guys doing those are kind of notorious for grabbing some random voltage regulator "with the same color wires" and not getting any charge.....

 

[bloglos]

I have one at 4.8 ohms and it's charging, I just got two of the racetech (on sale for $90) in the mail today, they ohmed out at 5.3 and 5.2 Quality looks reasonable, I will probably sand the face a bit before installing one. there is a bit of roughness at the copper phenolic interface. I will also do a "deck height" check vs the stock one when mounted. This has been an issue with some aftermarket rotors.

http://racetechelectric.com/c-701665-rotors-street-yamaha-rotors.html

But that's not your no slap issue I smell an issue with how your brushes are wired..... Picture of yours maybe?

I'll put up a picture when I get home from work today. Going by memory, there is a powered brown that extends the furthest of the two wires and powers the inside ring, and the green which connects to the outside ring which receives its signal from the regulator/rectifier when to ground. Does this sound right? The rec/reg is stock.

 

[bloglos]

OK! Update, it was the brushes. Replaced them and all is well. Charging fantastically.