Questions About Rectifier Testing

I've got a 1992 that won't spark, and is driving me crazy... But that really doesn't have much to do with the question. Or maybe it does.

I'm always on the hunt for used bikes, and I found a guy who is selling a 1986 Suzuki GS450 for very cheap. He claims that the regulator has gone bad. I don't have any experience with reg/recs so I thought I'd do a little "practice" on mine. The first test that the Haynes has you do on the system (page 9-25, section 32, #2-3 for those of you that have it) says:

That test checks out fine, but should I still get a reading if the ignition switch is off? Because I do, and that makes me wonder if I've got a short somewhere. I can't think of a reason why the manual would specify that the ignition should be ON if you'll get the reading either way. Makes me think something is wrong. The rest of the harness checks give good results.

Now, about the reg/rec itself... When testing in accordance with the manual, off the bike, I get no readings. Nothing. No resistance across any of the points. Would a bad reg/rec cause the bike not to spark? I've searched google and got mixed results.

I know that 3 out of 4 of my plug wires are bad (or not connected properly, they show no resistance), but the good wire doesn't spark either.


Thanks guys.

 

that red/wht wire is not switched to the reg, will always be hot

 

as for ohm test on r/r did you have your meter on ohms and r/r disconnected

 

what is your email, i will send you a pdf manual. haynes are garbage

 

or d/l here
VFR 750 Service Manual - VFR Discussion

 

The thing that struck me as odd was that the manual specified that the switch be on for that test. If it'll give the same reading whether the key is on or off, why specify? That's what had me scratching my head.

Yeah, the r/r was off the bike. Tested it while sitting on my couch. The meter was on ohms.

Thanks for that link. I'll download it and take a look.

 

page 251 has what you are after

 

all i can say is that is a haynes manual for you

 

I've never had trouble with Haynes. I've got one for each of my bikes and every truck I've owned, but I'll definitely print out this manual and cross-reference them both.

Still no-go on getting any readings out of the r/r, though. I ordered a new one and I'll test it the same way I did this one, so I know that my testing method (even though it's exactly as it's described in both manuals) is kosher.

Thanks again for that link, it'll be a lot of help.

 

oops sent wrong link then, pm me email

 

Does your meter have a 'diode' test function ? Looks like this [ -->|-- ]. Can also be used to check the RR.

If the range of the Ohms is not set correctly some meters will give a false negative reading such as you are reporting.

 

It does have a diode setting, and I used that also during the test... But I don't remember if it gave a reading or not. I'm out of town all weekend, so I won't be able to get back to it for a few days.

My multimeter is auto-ranging. I'll take a look in the manual, but I don't think there's a way to bypas that. It usually works pretty well, but I've also gotten good at moving the decimal place in my head when I need to.

Thanks for that heads-up.

 

When I got back home tonight, I retested the R/R, with some interesting results. This is the table I used for reference:



So you see, when I touch the pos. lead to prong 1, and the neg. lead to prongs 2-5, I should get readings on the multimeter. I don't. The meter continues to read "0.L" which i assume is this unit's equivalent to infinity.

HOWEVER - When I touch the NEG lead to prong 1, and the POS lead to any other prong, according to the table, I should get an "infinite" reading. Again, I don't. When I touch the NEG lead to prong 1 and the POS lead to 2-5, i get readings of 4.59MΩ, 4.40MΩ, 4.10MΩ, and 13.46MΩ, respectively. Notice that the table is in kΩ... Since 5MΩ = 5000kΩ, something seems to be out of whack here.

The same basic thing happens when I use the diode function. No reading where there should be readings, and readings where there shouldn't be.

I should have the new reg/rec in my hands tomorrow. I'll test it the same way and see what happens.

Thoughts?

 

Would you please check/verify the wiring in the plug with respect to the RR prongs--does prong 1 as shown in your diagram plug into the green wire in the connector? Prongs 2,3,4 go to the 3 yellow wires?

What's the make and model of your meter--some are positive ground ohmmeters, others are negative ground ohmmeters, and the results will be different for each as explained in the 2nd gen manual [but not for some reason in the 3rd gen manual].

 

Prong 1 is the red/white wire, 2-4 are yellow, and 5 is green:



Here's the chart from my Hayne's Manual. Same as the Honda chart, but with some different values:




Just a small copy of what I said above: When I touch the pos. lead to prong 1 (RED/WHITE), and the neg. lead to prongs 2-5 (2-4 YELLOW, 5 GREEN), I should get readings on the multimeter. I don't. The meter continues to read "0.L" which i assume is this unit's equivalent to infinity. But if I flip the meter leads around, I seem to get ridiculous readings in the MΩ range.

Essentially, red data is giving me no value, though it should, and yellow data is giving me solid values, though it shouldn't:




As far as the meter, it's a Innova 3320 that I picked up at Autozone.

 

Real-time example.

In this scenario (POS - Probe 1 (RED/WHITE), NEG - Probe 5 (GREEN)), I should see 0.7-15kΩ or 1-20kΩ, depending on which chart you look at:



But I get nothing.

Switch POS and NEG leads...



And I get a solid 16.40MΩ (not kΩ) when I should have an 'infinity' reading.


If you want to see any other combinations, let me know and I'll hook it up.

 

Colummn 1, Row 5 test on the old r/r:



And the new:




At least it's getting some reading, but why is it still showing me MΩ??

Plus, this new r/r is giving MΩ readings across all combination of prongs, even if the chart shows it should be reading 'infinite.' I'm thoroughly confused. I'll try to get my hands on another meter.

 

Testing off the bike can be inconclusive, confusing. Just plug it, start the bike, and see if charging voltage is within proper range ! Test stator resistances first.

 

If you had a known-to-be-good 10k or 20k resistor you could check your meter.

i think the chart in the manual is incorrect and pins 1 and 5 are mislabelled or reversed in the diagram. Putting the positive lead on prong 1 will result in infinite resistance since the path is blocked by the reverse bias on the diodes. Putting the positive lead on 2-5 will forward bias the diodes and result in either a voltage drop when using the diode test, or some tens of kohms resistance value. This agrees with your testing.

Please see the schematic below--the output terminal that goes to the battery positive is the red/white wire, called prong 1 in your pictures. Current flows in the direction of the diode arrowhead and is blocked in the opposite direction.

http://vfrworld.com/forums/mechanics-garage/36298-rectifier-regulator-schematic-specifications.html

 

Who knows what's going on, I certainly don't anymore! Like squirrelman said, I'm just going to plug it back in and make sure it's working properly... Once I can get the bike to fire, that is.

Once it stops raining, checking the stator and pulse generator is next on the list.