UP IN SMOKE!

sotxbill · Post by **sotxbill** » Fri Oct 23, 2009 12:19 pm

e3steve wrote:
Brew, all stators should read Open Circuit / no continuity / infinity (∞) to ground; a C/CA stator, I seem to recall, has a reading of between 1 & 3Ω (1.6Ω springs to mind, for some reason) across yellow & brown. Whatever is is, it's pretty low -- practically dead-short. If yellow to brown = R, then pink to brown = R∕2; that's the way the 3 coils are internally linked. The CB stator is different: pk-bn = R, pk-y = 2R & y-bn = 3R.

All readings should be checked after disconnecting those colours at the main harness-to-motor junction.
UPDATE: just measured my CB stator: pk-bn = 1R(Ω), pk-y = 1.6R & y-bn = 2.6R. This means that the CB diagram* must be correct and that my stator is a touch unbalanced, if within tolerance, with coil pair#1 being 0.6R, #2 being 1R & #3 being 1R.

Abstract: pk-bn routes via coil pair#2, pk-y via 1 & 3, y-bn via all 3 pairs. The pairs are diametrically coupled within the stator.

*concerning the alternator coils' internal connections!

Lots of ohm meters are not very accurate at the lower ranges. The 10% error or accuracy of a meter is only on the higher scales.At lower ohms measurements, the battery condition, and resistance of the leads and the lead connections start to introduce higher error. a half ohm of lead resistance means nothing when your measuring 20meg ohms.. but can be devestating when measuring one ohm. Pulling the leads out and clean them can eliminate up to 2 ohms of resistance typically. Then do you get full scale defection and can calibrate for battery variations?? Digital meters, some do if you touche the leads together can, most can. So you live with that understanding of error.

e3steve · Post by **e3steve** » Fri Oct 23, 2009 6:00 pm

Up to this point I've had a fair degree of support for your viewpoint and arguments, sotxbill. But now I'm starting to think that you're trying to teach abuela to suck huevos! You're treading on my toes within the scope of my profession. My Fluke DMMs are calibrated six-monthly in order to conform to ISO9002. I therefore have calibration certificates, and any deviation is accounted for; thus a correct(ed) reading is offered, supportable and appropriate.

Please do not automatically assume that you are in a position to question my published readings unless you are able to substantiate your own findings.

So you live with that understanding of error.

Every day, my friend -- every day! Ultimately understanding where the error lies, possessing the ability to pinpoint said error and, thus, to account for same, separates success from failure....

brewsky · Post by **brewsky** » Sat Oct 24, 2009 3:59 am

e3steve wrote: Every day, my friend -- every day! Ultimately understanding where the error lies, possessing the ability to pinpoint said error and, thus, to account for same, separates success from failure....

Amen to that!

brewsky · Post by **brewsky** » Sat Oct 24, 2009 6:36 pm

A good example of trying to figure out where the error is can be found here in this post!
http://www.honda305.com/forums/viewtopic.php?t=4748
Any suggestions?

Amysman63401 · Post by **Amysman63401** » Wed Aug 09, 2017 7:26 pm

Please correct me if I'm wrong. I believe the rectifier is bad on the '67 305 I'm working on. First time working on a motorcycle. It's been a chore but a very rewarding learning experience. I've tested the three wires from the stator. All read roughly 1.1 ohms. Am I wrong thinking the rectifier would be isolated from ground. I've taken the positive cable off, unplugged the connector for the three wires to the rectifier leaving the neg hooked up. When I hook multimeter leads to battery positive and other to any of the three posts on the rectifier, I get the voltage reading just as if I were touching both battery posts.
Battery not charging and drains quickly when running. Sorry so long. Thanks,Nick

e3steve · Post by **e3steve** » Thu Aug 10, 2017 2:19 am

Amysman63401 wrote:Please correct me if I'm wrong. I believe the rectifier is bad on the '67 305 I'm working on. First time working on a motorcycle. It's been a chore but a very rewarding learning experience. I've tested the three wires from the stator. All read roughly 1.1 ohms. Am I wrong thinking the rectifier would be isolated from ground. I've taken the positive cable off, unplugged the connector for the three wires to the rectifier leaving the neg hooked up. When I hook multimeter leads to battery positive and other to any of the three posts on the rectifier, I get the voltage reading just as if I were touching both battery posts.
Battery not charging and drains quickly when running. Sorry so long. Thanks,Nick

Welcome, Nick.

Am I right in assuming that your bike's a CB77 (being a '67) and has its original, red-painted rectifier fitted? You should get 12+VDC between the positive leg -- common with the battery positive -- and the stud & nut (negative) where it grounds to the mounting bracket.

What DC voltage do you get at those same points -- or across the battery posts -- with the motor running at around 2000rpm? Then that same reading with the lights switched on lo-beam?

Finally, if the battery is fully (bench) charged and left connected in place on the bike, does it discharge overnight?

And finally, finally: does the battery self-discharge (from fully bench-charged) overnight if it's left disconnected? Terminal voltage should read 13.8VDC - 15VDC when being bench-charged; that voltage would dip to no less than 12.9, perhaps 12.7V over ten hours' of being off-charge and disconnected.

SAFETY NOTE: Never, ever connect or disconnect a charger to or from the battery terminals without unplugging from the wall outlet! When a battery is being charged -- or being substantially discharged -- it 'gasses', giving off hydrogen, so don't create a spark or allow a naked flame in the same vicinity (the same room, with larger batteries)...

Amysman63401 · Post by **Amysman63401** » Thu Aug 10, 2017 6:29 am

Holy smokes, thank you. I didn't expect such a fast response since the last post on this thread was 2009. Well the brand new battery has developed a problem in the two weeks since I bought it online. It will only charge up to 10V. So I use the charger to give me that extra umph to start the bike. As soon as I get it started I turn off the charger then disconnect it. Thanks for the warning. I think next I'll try the car battery so I have full 12V. As it is within three minutes of running my voltage goes from 10v down to 8 or 7.
Oh ya, almost forgot. It's a ca77, and yes it's the original red painted rectifier.