The International CBX Owners Association

Well, during a nice 80 mls ride in perfect weather I saw my volt meter drop from 12V (which is actually about 13.5 V) to under 10V. The Voltage still went slightly up when revving higher, but ultimately at a traffic light literally 2 miles from home the bike died. I waited 5 minutes, disables the head light, bump started the bike (electric starter didn’t work anymore) and made it home. Now off to make good use of the forum search function to figure out where best to start diagnosing! Or maybe I ride my Airhead for a while….

Pic is from today’s ride with my buddy and his R90S that we fixed together. Happy rest of your Sunday everyone!

You will find lots of threads about alternator issues. Have you serviced the alternator since you had the bike? If not, then completely take it apart and check everything. Obviously brushes are the first and easiest thing to check. There are wear lines scribed into the brushes, the outer one will be worn more, and if down to the line, both should be replaced. If they are good, the next most common failure is the rotor. Check the resistance between the two copper rings. It must be 4 Ohms, plus or minus a couple of tenths. Out of this range, high or low, you have a bad rotor. Then report back, but almost figure on two new bearings and the center seal, plus the shaft o-ring. And a cover gasket.

Very occasionally you will find a bad regulator, and even more rarely, a bad stator.

Dave

Thanks Dave. The only thing I know at this point is that it does not seem to be the battery (it's new and I load tested it before putting it in) and the late previous owner wrote in his documentation that "the only expenditure I have had was rebuilding all the alternator components due to weak charging output". Looking forward to digging in!

While you are at it, do your charging system a favor and convert to LEDs. Just doing the headlight and taillight will save 50 watts.

http://www.cbxclub.com/forum/viewtopic.php?t=11771

I will add to the excellent advice above, check your connections in the charging circuit. Look for signs of overheating.

Yes, yesterday was great riding in the Hill Country. We rode from Bandera to Frederickburg, to Willow, then down to Luckenbach, and back to Bandera a very nice 200 mile loop.

But, I was on the Griso, as the CBX is back home.

Joe, Thanks for the link to the thread. I have converted my G/S Airhead headlight to LED (Cyclops), it made a big difference. Will definitely check out this thread.

Rick, we only did FM 1431 and Cow Creek Road, was the first long ride on my CBX and I am glad I didn't go any further, wouldn't have made it another 5 miles! Definitely perfect riding weather here these days!!

Nobody points to the red connector being corroded?

Rick - you didn't run into Waylon, Willie and the Boys?

Dave

He will find out about the red connector when he removes the alternator.

Dave

daves79x wrote: ↑

Mon Mar 06, 2023 2:11 pm

He will find out about the red connector when he removes the alternator.

Dave

You are building up the tension, this is better than Christmas Eve!

I have to tend to my very original G/S for a bit as well, I have been invited to show the bike at the Handbuilt Show in Austin. It is a show for custom bikes mainly, but every once in a while people want to rest their eyes and look at something old and original I guess! In case anyone is intersted, here are some pics from last year.

https://www.youtube.com/watch?v=dA_cI9T ... MzAyMjAyMw

EMS wrote: ↑

Mon Mar 06, 2023 11:26 am

Nobody points to the red connector being corroded?

I hinted at that when I suggested checking all the connections. He'll get there.

So I ran a few tests:
Battery: was down to 11.9 Volt, charged and load tested, passed
Brushes: look good, far away from the line
Rotor: 4.0 to 4.1 Ohms between the two rings
Stator: 0 Ohms between the 3 phases, continuity from the brushes to the other 2 cables
Clutch looks ok, I think, spring free length exactly 30.0mm

It looks like wiring (and probably brushes) have been replaced at some points. There was some corrosion and melting in the connector, specifically the middle one. Not sure about the rotor rings, they look a bit worn. Any suggestions what to check next? Thanks!

Everything you checked seems OK. You might shine up the rings with some Scotchbrite, make sure to blow off the residue. Make sure the bearings are smooth. You need to cut the old connector from the alternator wire, I use a Dremmel and a cut-off wheel to carve out the melted plastic, then pull out the connectors. Clean them up and source a new 6-pin connector, several places to get them. That is likely not you charging issue though. Get a known good regulator and plug it in to test - it can just hang, does not need to be grounded. That is likely your problem. While you are fiddling with electrics you should measure the voltage drop from your battery to the coils. Should be less than a volt. If more, all connections need cleaned, especially the ignition switch and kill switch - power to the coils goes through all those.

Sounds like a good plan, thanks! I'll get to it in the next days.

daves79x wrote: ↑

Mon Mar 06, 2023 2:10 pm

Rick - you didn't run into Waylon, Willie and the Boys?

Dave

No, but there was a very talented young lady on stage who wrote her own songs, and performed them very well. I'm no c/w fan, but can appreciate talent.

Apparently, the venue has been bought by some business people and has turned into a tourist trap. Guilty......

No CBX's there, only a couple interesting bikes in a sea of chrome and noise. I did spot a nice R100GS that had been re-done.