Help-how to check if R/R is the problem

My battery is not getting the proper Voltage and left me stranded.When I checked my DC power to the battery I get 12 V at idle and 12.5V at 5rpm.
I know it should be higher.
What is the easiest way to check if Regulator Rectifier is the culprit.I don't want to buy parts I don't need.
Manual instruction checking this confuses me a lot.
Thank you guys!

 

can someone clarify what "continuity" means
When checking green and ground wires on RR manual says continuity should exist. I am guessing battery voltage but could be discharge voltage too right?

 

Continuity means that you will get power through it. For example, a piece of wire will have continuity if it is not damaged.

There should be a selection on your multimeter for continuity. Many times that selection will have a high pitched tone when continuity is detected. If you were to take the meter leads and touch them together you will hear the tone. The tone lets you know that you have continuity.

Sorry, I have never checked an R/R.

 

Do the test for your Stator as it is easy to understand and if it reads within spec good.

The test your battery, you may have to take it to AutoZone or NAPA so they can ttest it or a bike shop.

If your battery is good and your stator is good your RR is bad. The test procedure for the RR is crap in the manuel. You can have a bad RR and it will almost always pass the test in the manuel.

The easiest test is take the bike for a quick ride and make sure she is warmed up and put your multileter on the 20 volt setting and with the leads on the battery terminals rev it up 5000 rpms and hold and see what reading you get. It lets you know their is a charging issue. What that issue is could be one of the three parts just discussed.

BZ

 

Thank you for an intelligent relpy Tink; I needed this today.

BZ

 

Thank you guys.Here is a quick question

Do I check the Stator yellow wires for resistance with engine off or on.Manual does not say.
Set multimeter on resistance scale(ohms Ω). Test resistance between each of the three wires coming off of the stator. 1-2, 2-3, 3-1. Resistance should be present, it will vary depending on type of stator. If there is no resistance between any two leads, the stator is bad.

 

That prettry well sums it up !

Of course you need to inspect r/r plugs and the main connection on top of starter relay first.

 

Tinki also needed to mention that sometimes a stator will test OK at rest, but an open circuit (no charging) can develop at operating temperature when engine is hot.

 

I just want to thank everyone for all the feedback.
I did all the tests (amateur like me its a big deal) and R/R was fried.
I ordered RMstator beefier one for $99 about $50 less then OEM.
Everything is working fine now.Thank you again

 

Or just select ohms X 1000 scale.
Once you learn to use a multimeter, you will save thousands of dollars.

 

Okay, so this just happened to me the other day. I noticed that after running the bike for a while, it wouldn't start back up if shut off for less than a minute. If I waited a while, my battery would slowly gain back it's voltage high enough to run the starter. Essentially just living off the battery. After checking all my connectors, no bad or burnt connections, I did the continuity check for the stator. Measured within tolerance, so I started it up and measured 14.5-17.0V AC (idle-4000rpm) on all three yellow wires to ground. So everything points to a bad R/R. The one I have is a Rick's R/R which has lasted 12K miles(two Maine summers), but this time I opted to just get one that works for cheap. So, found one on ebay from parted RC-51 for 25 bucks and will just wire it to work. Most all motorcycle rectifier/regulators work in the same way. 3 "phases", + and - (these may be doubled).The only differences I think is the Wattage capability of the R/R. My dad's -81 CB400t has an R/R that would fit the 5th gen, but the wires are smaller gauge. Hopefully somebody finds this useful -Andy