Regulator checking help?

[Joolstacho]

Kerry's info is useful, but unfortunately there's no info on checking the regulator/rectifier.
Clymer manual shows it - checking resistance over the reg/rec plug terminals etc, but you need a meter that is accurate to 1ohm as the values are 6ohms (I guess 10 ohms would be ok as you'd see a fraction?) My cheapo meter only goes down to 200ohms.
I'm getting 75 vac out of my alternator so that's good. Across the battery terminals I'm seeing only 12.9v at tickover, and 12.8v at 5000rpm. This is too low obviously - should be 13.5-15v.
I've checked and cleaned the reg/rec plugs.
Q: Are there any checks I could do on the reg/rec with a meter that goes down to 200ohms? Obviously I don't want to buy another reg/rec until I confirm mine is stuffed.
I'm tempted to try one off a CX500 (I have a spare), but I don't want to blow anything.
Or is there anything else it could be causing the problem?
-Jools

[radodrill]

The Suzuki manual's table lists the resistances for the Suzuki pocket meter.  More or less you're checking for continuity only in one direction through the diodes within the rectifier; so where the table says 6Ohm you should have continuity (needle at the bottom) and where the table says infinity you won't have continuity (needle won't move).

[Joolstacho]

Yup, get all that -my point is, is there any way to test it without the Suzuki pocket tester or a super-dooper 1ohm meter?

[adidasguy]

A digital meter with 4 digits on a 200 ohm scale will read in tenths. You can read low resistance.

A trick is to see what it reads with the probes touching. Cheap meters might read something. Good meters should show zero or have a button to zero the meter.

Then take your readings. Subtract off what the reading was with the probes touching each other. Now you have a fairly accurate reading.

[Joolstacho]

Ooh good tip, I'll try that.
Next question: Are E model regs and F model regs interchangeable?

[adidasguy]

Yes they are. However some are physically slightly different and may need longer mounting screws.
Buy the newest you can get.
Have you eliminated battery as the problem?

[Joolstacho]

Thanks mate, I can get an F model type reg at a reasonable price, -I can adapt the mounting and plugs (if necessary) no prob, now I know the electronics are the same, I'll go for it.
(Yup, I'm using a brand new Motobatt battery).
Cheers.

[Joolstacho]

Next thing -to find out why my reg/rec failed.
I guess they can fail due to old age, but possibly a short somewhere? -I did find one coil wire off it's terminal, if that hit an earth maybe that caused it?

[adidasguy]

A short could do it.
We probably would have suggested the regulator right away if we knew there was a short to the frame.
You can buy a used one. New OEM ones are about $120 - which is the same price as an improved MosFet regulator. If spending over $100, then get the improved MosFet ones. They are better designed and are supposed to quietly shut off if a short or overheated then turn back on when things are OK.
Post a want-to-buy. Members have extras. I can check my parts bin for extras that are checked out as working.

[Joolstacho]

Life's a laugh init ! 
I bought a used (guaranteed) one on the bay for $35 delivered, then later in the day dropped in to a mate's place and he casually pulled a brand new one off his shelves and handed it to me.
Test it tomorrow.
Thanks for your advice adidasguy, you're a legend.
-Jools

[Joolstacho]

Next Q: Are the 3 yellow (alternator into reg/rec) wires interchangeable? (The new reg has a different plugging arrangement as it's been used for testing purposes)

[adidasguy]

Yellow is yellow. Connect the 3 any way you desire.
It is a 3 phase AC generator, so doesn't matter.

[Joolstacho]

Cheers. (now I can plug it in without the fear of acrid smoke!)

At the risk of making a meal of this subject, I found the following reg/rec test info at Racetech Electric... here:
http://racetechelectric.com/ft-751-voltage-regulators.html
that might help others.

-Jools

[gl0ckage]

A question, does the regulator have to be bolted? I want mine laying flat on my frame with hinges to keep it there.

[adidasguy]

Nope. Can be anywhere it has air flow. It gets very warm and needs air.

[yamahonkawazuki]

Have you eliminated battery as the problem?

yup KGB   
Known Good Battery ( start with )