My CB77 No Longer Charges the Battery

sarals · Post by **sarals** » Thu Jun 12, 2014 11:33 am

Here's the results of the test.

Brown wire, 4000 RPM - 6.01 volts
Yellow wire, 4000 RPM - 6.00 volts
Pink wire, 4000 RPM - 6.01 volts

Low. Something is apparently wrong with the stator coil. Or, the magnets are weak in the rotor. Either is not good.

The Podtronics apparently works fine.

sarals · Post by **sarals** » Thu Jun 12, 2014 5:30 pm

It's looking more and more like a bad stator, specifically, the yellow wire leg.

I tested the resistance between the brown/yellow and brown/pink wires. There should be no more than 2 ohms. I had 2.5 between brown/yellow, and 1.5 between brown/pink.

AC voltage across those pairs was 50 VAC across brown/yellow, 62 VAC across brown/pink.

The Podtronics is good. So is the battery. The stator apparently isn't.

brewsky · Post by **brewsky** » Fri Jun 13, 2014 3:18 am

The resistance values don't look bad to me.
See values in this thread:
http://www.honda305.com/forums/up-in-sm ... ight=smoke
I would be suspect of the AC values though.
I would try replacing the podtronics with a $3 Radio Shack rectifier, before I gave up on the stator.
Is it possible you have some wires crossed somewhere?

sarals · Post by **sarals** » Fri Jun 13, 2014 4:08 pm

brewsky wrote:The resistance values don't look bad to me.
See values in this thread:
http://www.honda305.com/forums/up-in-sm ... ight=smoke
I would be suspect of the AC values though.
I would try replacing the podtronics with a $3 Radio Shack rectifier, before I gave up on the stator.
Is it possible you have some wires crossed somewhere?

Anything is possible! The AC voltage was taken directly from the stator wires, disconnected from the main harness.

I'm about to try one of the Radio Shack rectifiers. I'll report back.

sarals · Post by **sarals** » Fri Jun 13, 2014 5:06 pm

With the Radio Shack rectifier in place of the Podtronics, 12.87 volts maximum. The same as the Podtronics.

The Podtronics regulates by using a zener diode, which has a threshold voltage of 13.8 volts (I read that somewhere). So, the generator isn't even getting close to threshold voltage for the Podtronics.

I'm really thinking something is amiss in that stator coil. I'll pull if off next week and see what I can find in it.

Crap.

Vince Lupo · Post by **Vince Lupo** » Sat Jun 14, 2014 6:03 am

Been down this same road. I am using the RetroBikes rectifier (looks like the original, but has a diode in it), a Rick's Motorsport Electrics stator, an early NOS rotor, PowerSonic gel battery. Not cheap, but it gets me over 14 volts. Will gladly spend the money for peace of mind.

The Rick's stator is discontinued, but Smith Family Powersports in Missouri has one left (this is where I got mine): http://www.amazon.com/RICKS-ELECTRIC-H- ... B008YIFPL4

You may want to contact them directly to confirm that they have it. The Rick's part number is 99-102.

Rick's does offer a stator rewinding service, but sadly not for the CB77.

NOS rotors cost about $350 - I got mine from Terry at Western Hills. If you do decide to go that route, try to find an earlier rotor (without the 'L' stamped), as supposedly they put out more power. However, there's no guarantee with even an NOS rotor - they're 50+ years old, and who knows how they've been stored all this time and if the magnetism has degraded.

One way to check your rotor is to simply stick a screwdriver against it and see how difficult it is to pull off. Not very scientific, of course, but at least it can give you a little idea as to how much magnetism is there.

It's been said that our 'charging systems' were more 'maintenance systems'. Not sure what they were to have originally put out, but around 13 volts may have been it. I've had other Hondas in the past, and in general I've found their charging systems to be marginal. It may still be true today!

48lesco · Post by **48lesco** » Sat Jun 14, 2014 7:34 am

I'm kind of a stickler for originality, and I like to experience the design and engineering as well as the look and feel of these old bikes. I currently have two '66 Dreams and a '64 Superhawk on the road. All have completely OEM electrical systems down to the meter bulbs, except for the batteries which are the cheapest lead-acid ones I can buy, usually from Partzilla. I only ride the back roads here in Ohio, almost never over 50mph. I use the headlights sparingly. I don't have turn signals. In the winter the batteries stay in the basement on battery tenders and I usually get three seasons out of them. Now, if you do a lot of highway riding, or riding at night, your results may vary, but I can't recall ever having a charging system issue (knocking on wood now). Could you improve the the electrical system on these bikes? Sure, but the system was designed with the components it came with, not an upgraded battery or halogen headlight, not electronic ignition or a "better" rectifier. Change one component, and none of the others in the system function exactly as designed. I would always tend to revert back to what Honda designed. Just my $.02
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