Do check rotor magnetism. It caught me out when looking for a charging problem. The rotor that had worked from new, just totally lost all magnetism. I do note that Stuart has mentioned the rotor magnetism.
Thank you for your response. The advice given on this forum is invaluable.I fully get why you’re doing that Steve and in your position (where I was a year ago) I’d do the same. For fifty bucks you can eliminate the possibility of a faulty zener diode and/or rectifier but do follow Stuart’s advice and buy a 3-phase unit, if you find later that the alternator stator needs replacing you’ll be able to upgrade to 3-phase charging, more volts at lower revs than single phase. You won’t be able to do that if you buy the item linked.
The advice offered on this forum is invaluable, without it I would’ve sold my bike on before now. It just takes a while for me to fully understand what’s being said and then figure out if I have all of the correct tools/components to follow the advice.
decided to abandon the stock Zener and rectifier and install a Podtronics and hope my alternator is ok.
Hopefully this solves the electrical issues.FREE SHIPPING on ALL domestic orders! Everything you need for your classic vintage British Triumph, Norton, BSA motorcycle parts.thebonnevilleshop.com
Three things:-Do check rotor magnetism. It caught me out when looking for a charging problem. The rotor that had worked from new, just totally lost all magnetism.
. Whichever Pod you buy, be aware the fitting instructions are ridiculously over-complicated, waffling on about "ground" and similar, which is irrelevant.posting again when the Podtronics has arrived and installed.
I'll save Steve the bother. I was actually checking the ignition timing and removing the primary inspection cover suggested all was not well. Further investigation revealed a stator which had clearly overheated. I'd only owned the bike for about a week and so panicked replacing the RM21 stator like for like, I'd do it differently now. Note the bloodstained old T-shirt indicating that I hadn't yet figured out where the finger/knuckle traps were.
As usual your information is more then useful.Hi Steve,
. While I sincerely hope the Pod fixes your bike's electrical problems, a primary case gasket would've been a wiser and cheaper first investment. While it'd be tedious for you to look back through @Rusty1's posts, he'll confirm the reason he found for the lack of charging on his then newly-acquired T100R was damage caused by contact between rotor and stator, something he didn't see 'til he took off the primary cover ... Otoh, if you did that but didn't find any stator or rotor failures, the price of the replacement primary gasket would've been a lot less to waste than the price of the Pod if your bike's problem turns out not to be rectifier or Zener?
. The Pod you've ordered is the poorest value from TBS. The 200W single-phase one - that'll work with both your bike's existing stator and at least a higher-output single-phase stator - is cheaper (by a buck ); the 3-phase one I recommended is only a buck more. As you've bought the Pod from TBS, why don't you just 'phone or email 'em and ask if they'll change it?
. Whichever Pod you buy, be aware the fitting instructions are ridiculously over-complicated, waffling on about "ground" and similar, which is irrelevant.
On your bike:-
.. Follow the black alternator stator lead from where it emerges from the primary chaincase to the two bullet snap connectors (White/Green and Green/Yellow wires. Disconnect the snap connectors.
.. Connect each stator wire to one of the Pod's Yellow wires. Doesn't matter which way 'round as the alternator produces AC. If you're using a 3-phase Pod, insulate the end of the unused Yellow wire.
.. Connect the Pod Red wire directly to the battery positive terminal. As I say, ignore all the confusing drivel about "ground", makes absolutely no electrical difference whatsoever.
.. Assuming your bike is a standard T100C - specifically without an Ammeter mounted in the headlamp shell - connect the Pod Black wire directly to the battery negative terminal.
.. One thing not mentioned in Pod (any reg./rec.?) fitting instructions - but I do - is install a fuse in either the Red or Black wire between battery and Pod (any reg./rec.), doesn't matter which of the wires. Reason is otherwise it's only the reg./rec. electronics preventing a short-circuit - they don't fail regularly but it isn't unknown. Fuse for a standard alternator is 15A (because the next-lower blade fuse is 10A and that equates to standard 120W); if you fit a high-output stator, the fuse should be 20A.
.. Again assuming standard T100C, disconnect and securely insulate the Brown/Blue wires terminals that were on rectifier and Zener. Risking stating the obvious, don't just cut them off - Brown/Blue connects from battery -ve to the ignition switch.
Thanks for your post and pics!I'll save Steve the bother. I was actually checking the ignition timing and removing the primary inspection cover suggested all was not well. Further investigation revealed a stator which had clearly overheated. I'd only owned the bike for about a week and so panicked replacing the RM21 stator like for like, I'd do it differently now. Note the bloodstained old T-shirt indicating that I hadn't yet figured out where the finger/knuckle traps were. View attachment 715822 View attachment 715823
EUREKA!Hi, Interesting Rambo's rotor demagnetized quickly. Was looked at shop manual, Section H4, Part B, step (III).
A paraphrase is, if output of alternator test at the stator leads are low in all tests there may be problem with alternator leads rubbing chain or the like. Or... rotor is partially demagnetized. Faulty rectifier could be a cause of loss. ( A shorted diode comes to mind, as an open diode wouldn't seem to cause that). Manual goes on to say battery of incorrect polarity (hooked up backwards??) can cause rotor demagnetize. Goes on to say, rectifier & battery polarity need to be verified good/correct before replacing rotor.
The manual says first test of charging system is alternator output voltage between the 2 leads with leads disconnected & hooked to 1 ohm resistor. 9v or greater.
Here's a question I certainly don't know answer to. If you get 9v or above with proper 1 ohm resistor at 3000rpm, would that imply rotor is good??? I don't know!
My hunch is if you worked at dealership for 5-10 years, you'd get a feel for this. I suppose most of those old guys have passed away by now.
Interesting stuff. Again I don't have 1 ohm resistor & have never done the above test. Looking like I need to get a resistor.
After a life time of tech in car dealerships we learned a lot of stuff about diagnostics. Pretty much got a system down on charging problems that worked well in real life. Crazy as it sounds, basically followed factory procedure to letter.
I feel if... you had a test kit put together with known good battery, 1 ohm resistor, complete set of home made test leads volt & amp meter you could pretty accurately diagnose most charging problems in 30-45 min. The system is very simple really. Intermittent problems are every tech's nightmare, but most problems are not intermittent.
One thing I learned long ago is multiple problems are common. You repair what fails test. Continue testing & when another failure is found repair that. Then continue test, repair procedures until verify all else is working properly.
In my mind this is important stuff to those that want maximum reliability without throwing parts at bike.
Once again, many thanks to you and all the other guys that offered their advice.Hi Steve, Congratulations, that's great news!! Sometimes it's process we go through sorting these bikes. Often not easy.
Your readings indicate you are charging now & battery is working very good. After a hundred miles or so do the same check & see where your at. Of course if bike continues to start & run good, you'll expect good readings.
No rush at all! If you have some spare time can you test your rectifier for me. I'm most curious for my own knowledge. Thank you very much!
Use ohm scale not diode test. Make sure your leads are black on common, red on volts/ohms on meter.
Here's the test procedure. Not a perfect test, but will show major faults. I'll repost it here.
Set ohm scale so you can read in the 100-300 ohm range. A good diode will read between 100 & 250 ohm or so one way & OL with leads reversed...
If your meter is not set to correct scale it may read OL (open lead(open circuit)) when it's not really open circuit. If the upper boxes of test are all OL your meter is probably set wrong. Once you feel meter is set correctly fill out the boxes with what meter reads.
The lower boxes will probably all read OL, but if not fill out the boxes with what your meter says.
The boxes are numbered 1-8 fill in your reading in each box.
It is imperative your leads are hooked to rectifier in the direction as shown on test sheet. Notice how the leads are reversed on each side of center, depending on what box you are measuring. Do not mess this up or test won't be valid!
Note the center bolt is connected to both end discs. If needed take a sharp knife & scrape paint of edge of disc on the out side disc but you should be able to make contact to the center bolt via the little 1/4 connector under nut head or the mounting threads.
Notice the dome on the discs... That is where the diodes actually are. The are bonded into the disc itself inside the dome.
I think I said prior but the 3 center discs are insulated from the center bolt with plastic bushings & spacers. These are very rugged & unlikely to fail.
I recommend printing the test sheet & filling it in. Scan & post it or simply post what the reading is for each numbered box.
If you mess up on testing, I'll probably be able to see that & we'll try again. Takes some practice. If I see your readings look valid, we'll have a rough idea of the condition of your old rectifier. That will tell you a lot. Since it's not practical to do long road test at this time of year it will let you know if it was more or less likely to contribute to your problems.
Thanks again, Don View attachment 716275
Excellent! Yes.looks like the starting problem is solved.
latest voltage readings;
in the ball park?
No worries. The tests themselves are actually very simple, it's writing and reading them that makes 'em look complicated.my old gray matter gets jumbled.
Yes.The manual says first test of charging system is alternator output voltage between the 2 leads with leads disconnected & hooked to 1 ohm resistor. 9v or greater.
If you get 9v or above with proper 1 ohm resistor at 3000rpm, would that imply rotor is good?
"Magnetoman" on BritBike has recommended me to Ohmite 100W; they also do 175W (L175J1R0E) and 225W (L225J1R0E).Looking like I need to get a resistor.
It might not have done, might've demagnetised slowly but not noticeably, 'til the effects were noticed ...Interesting Rambo's rotor demagnetized quickly.
Don,Hi Steve, I don't want you to return to stock. No reason to do that.
I'm trying to learn more about what voltage reading might relate to what the fault might be. So... If you'd be so kind to print test sheet. Stick it in your tool box. A dark rainy night when nothing is on TV & Momma (wife) is driving you nuts. Put the ohm meter on it. I'd appreciate it. Again no rush. You need a break & a ride.
Well it looks like my bike is starting and running good!!Hi,
No worries. The tests themselves are actually very simple, it's writing and reading them that makes 'em look complicated.
Two reasons for the resistor:-
. It's a 'load' on the alternator, like the normal connection to rectifier or reg./rec. and DC system. If the alternator's two or three wires are simply connected together, the only 'load' is the (low) resistance of the stator coils themselves.
. 1 Ohm because it's in parallel with a Voltmeter, more likely to be found in even a dealer's workshop 'back in the day' than a specific automotive Ammeter. Then Ohm's Law (Volts = Amps x Ohms, E=IR) says the indicated Volts are also the Amps. Elsewhere, Lucas advertised 75% of rated @ 2,400 rpm for the 2-wire single-phase alternators, the RM21 fitted as standard to Triumph twins from about '69 was rated for 10.5A @ 5,000 rpm, so 7.875A @ 2,400 so 9A @ 3,000 was comfortably above.
"Magnetoman" on BritBike has recommended me to Ohmite 100W; they also do 175W (L175J1R0E) and 225W (L225J1R0E).
It might not have done, might've demagnetised slowly but not noticeably, 'til the effects were noticed ...