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Discussion Starter · #1 ·
I went for my first ride (longer than around the block) this evening for about 40 miles on my 1968 Honda CL350. At the end of 20 miles the electric starter would not work but I still had a strong headlight (not running headlight while riding unless it's dark). When I got home (night ride with headlight on) after the second 20 miles it would not start with the electric starter again. I kick started it and, while running, checked the battery voltage. At idle it was about 12.05v (11.75v with key off) and would jump to only 12.25v when the engine was revved to over 2000rpm. It had a new battery about 2 months ago with very little riding.

I checked the rectifier in both directions with a digital meter and got about 37k ohm in one direction and about 3.5k ohm in the other so I'm assuming the rectifier is good (it's the original part).

My next thought is that I have a bad regulator (3 wires, blk/grn/yellow). Can anyone recommend a procedure to verify the regulator is functioning properly?

I will be ordering a rectifier since it makes sense as a preventative measure but I don't want to shell out $90 for a regulator w/o verifying it's not functioning properly.

Any help would be appreciated.
 

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Sensei
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Mike.... According to your readings, the rectifier is bad...... It should read a number (continuity) in one direction only (infinate resistance in the reversed direction...NO continuity)......Between EVERY pair of wires (yellow to green, yellow to red/white, yellow to pink, red/white to green, red/white to pink, and pink to green)... The numerical value may vary depending on how many diodes you are reading through, but it MUST only flow in one direction across any pair.... You may want to jumper the white and yellow together for a full-time overcharge mode as well, the charging systems on these bikes are nominal at best....
Once the rectifier is good, I'll go into the regulator test.....Steve
 

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Discussion Starter · #3 ·
66Sprint said:
Mike.... According to your readings, the rectifier is bad...... It should read a number (continuity) in one direction only (infinate resistance in the reversed direction)......Between EVERY pair of wires (yellow to green, yellow to red/white, yellow to pink, red/white to green, red/white to pink, and pink to green)... The numerical value may vary depending on how many diodes you are reading through, but it MUST only flow in one direction across any pair....
Once the rectifier is good, I'll go into the regulator test.....Steve
Hmmm, let me go check again. That's the problem with a digital meter, the values can sometime confuse my old brain. With my old Simpson 260 meter (long since gone) it was either on/off basically.

The meter I have has a diode checking capability and the rectifier checks good by showing OL in one direction and 250ma in the other. You can see the procedure for checking the diode here http://support.radioshack.com/support_m ... /64777.pdf on page 23.

In my past life, when checking diodes we usually checked forward resistance vs. reverse resistance and looked for a large variance which, if both directions showed either a short or an open in bother directions then we called the component bad. If there was a larger variance then we assumed it was good. In this case 37k ohm vs 5k ohm.

Remember, this is 30 year old military electronics in an enviroment where we didn't have a lot of options when it came time to replace parts. :D And, seriously, I have trouble remembering this stuff.

Anyway, your suggestion got me thinking I should go back and repeat the test using the diode function and I think the rectifier is probably good.

Would your suggestion re: checking the regulator be to check the input voltage and then check the output voltage with the engine running? My manual doesn't do a good job of showing which wire colors are which.

Besides, I think it's a good idea to document this sort of stuff for future reference and searches.

Thanks for your help.

P.S. I went back to the manual read a little more. It states when checking the rectifier that resistance should be checked in both forward and reverse directions. They list the values as 600 ohm in one direction and 5-40 ohm in the other. That seems kind of a low value to me but then the equipment they depict in the pictures was older than even what I'm used to using. :lol:
 

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Sensei
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Nope...Assuming the rectifier is now good, simply unplug ALL three regulator leads, and read running voltage at the battery....SLOWLY rev the engine, reading DCV at the battery ... IT SHOULD gofrom 11.5 at idle to about 14V by around 4000 (sometimes less) RPM...... DON'T rev any higher than necessary to get a 14VDC reading!.... Plugging a good Regulator into the system SHOULD limit DC voltage (at the battery) to somewhere between 13.7 and 14.2V regardless of revs......(although I've seen some examples that allow 14.4 on MY meter).... ANY voltage in excess of 15V will damage the battery eventually, less than 13 won't recharge the battery quickly enough......

I don't understand where your "manual" got those figures... A good diode ONLY flows in ONE direction, NOT both.........
 

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Discussion Starter · #5 ·
66Sprint said:
Nope...Assuming the rectifier is now good, simply unplug ALL three regulator leads, and read running voltage at the battery....SLOWLY rev the engine, reading DCV at the battery ... IT SHOULD gofrom 11.5 at idle to about 14V by around 4000 (sometimes less) RPM...... DON'T rev any higher than necessary to get a 14VDC reading!.... Plugging a good Regulator into the system SHOULD limit DC voltage (at the battery) to somewhere between 13.7 and 14.2V regardless of revs......(although I've seen some examples that allow 14.4 on MY meter).... ANY voltage in excess of 15V will damage the battery eventually, less than 13 won't recharge the battery quickly enough......
Gotcha, take regulator out of circuit and we should see lots of V as the engine revs (slowly). If I plug the same regulator back in and don't read more than 12.2 v with engine revving then I've got a bad regulator.

'Preciate the help.
 

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Sensei
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Mike...Which part was actually bad?.... (others will be doing similar troubleshoots...)
 

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Discussion Starter · #7 ·
66Sprint said:
Mike...Which part was actually bad?.... (others will be doing similar troubleshoots...)
I haven't put it back together yet, maybe later this afternoon. The CL's are a pain. For me, it seems I have to pull the left side cover to do anything and that means pulling the pips almost all the way off. I guess there is something to be said for the CB style.

It's interesting, I got a message back from the guy who owns Oregon Motorcycle Parts (he sells the retofit versions for the rectifier and regulator). He said I should just take the regulator and throw it away. He said if I didn't have any accessories or electronic ignition and ran the headlight on all the time (like most states require) then I didn't even need the regulator on these old bikes. I doubt that I will do that since that would be a big paradigm shift that I don't think I can get over. :)
 

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Interesting point he makes.

Especially since these regulators just shunt any current to ground when voltage gets too high. It's not like some bikes where they're actively varying a field current to actually vary the alternator's output.

If you just got rid of the regulator, you could theoretically be still trying to push current into the battery even tho the battery voltage is high enough. I guess he's probably right - I never met a vintage Honda that was capable of OVERcharging a battery unless it was by riding with the lights off, at high engine RPMs for hours straight... :D
 

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Discussion Starter · #9 ·
kirkn said:
Interesting point he makes.

Especially since these regulators just shunt any current to ground when voltage gets too high. It's not like some bikes where they're actively varying a field current to actually vary the alternator's output.

If you just got rid of the regulator, you could theoretically be still trying to push current into the battery even tho the battery voltage is high enough. I guess he's probably right - I never met a vintage Honda that was capable of OVERcharging a battery unless it was by riding with the lights off, at high engine RPMs for hours straight... :D
I think that was his point. However, it also takes out a safety point. The headlight could fail, the switch accidently turned of etc.. Lots of things can go wrong that could cause a problem so, while I feel better about riding without one for a short period, I think I'll spend the money and replace it. Most of the riding I will do with this bike will be in the 55 mph range is which is around 6000 rpm where the alternator is spinning pretty quick.
 

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Discussion Starter · #10 ·
Well, I went out and disconnected the regulator and fired the bike up after re installing the exhaust system. I revved the bike to about 5K and the battery voltage would go to about 12.8v or so. When I turned on the headlight the voltage would slowing rise to about 13.2v.

I re-connected the regulator and everything worked the same. Hmmmmm, that's odd. The only thing I can think is that the connections for the regulator might have been a little corroded and that why I had the poor readings the first time.

I'm curious why the voltage would go UP when I turn the headlight on though. I seem to recall reading somewhere that when the headlight switch is turned on that it uses another one of the field coils but I'm hazy on this point.

Anyway, it seems to be working fine now so I put everything back together and installed a new left hand switch assembly that I got off eBay. The old one was broken where the mirror screws in so now I have two mirrors and it looks nice. After that, I went for a nice 50 mile ride. Some of it was on 60 mph Texas County Roads and on the way back I found some nice 45-50 mph winding back roads that this thing was built for.

While I had a good time (and will continue to do so) I think the reality of riding this thing is quite a bit different than my memories of riding this bike when I was 14-16. I'm going to think about it a little bit more and try to capture my thoughts and feelings then write something up. I haven't made that many stops yet but it's surprising to have people walk up and just look at the bike and start talking about the "bike they used to have that was a lot like that one". :)

In the short term I've still got to paint the new tank and as soon as the wind dies down and I can spray paint outside I'll attempt to paint it.

I've ridden the bike about 100 miles this week and I've still got a big grin
 

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Mike-

Turning the headlight on does indeed kick in the third charging coil.
A lot of us just permanently connect the yellow and white/yellow wires in the headlight shell (coming from the main harness). That's the same thing the headlight switch does when you turn on the lights.
On our older bikes (so old that we still have a lights-off position on out handlebar switch), that keeps the max charging going on even with the lights off.
These marginal electrics need all the help they can get.
 

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Discussion Starter · #12 ·
tbpmusic said:
Mike-

Turning the headlight on does indeed kick in the third charging coil.
A lot of us just permanently connect the yellow and white/yellow wires in the headlight shell (coming from the main harness). That's the same thing the headlight switch does when you turn on the lights.
On our older bikes (so old that we still have a lights-off position on out handlebar switch), that keeps the max charging going on even with the lights off.
These marginal electrics need all the help they can get.
Thanks for the reminder on that Bill. I'll dig in there and make that change tomorrow.
 

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anything else about throwing the regulator out? I had a guy at a shop that used to work on these say the same thing to me the other day....
 
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