CB77 Charging Output

[fatalbert]

I bought a 1966 CB77 I plan to restore. The previous owner said that if you run with the headlight on all the time as required in Washington state that the battery will go dead. I don't remember this being a problem way back when so would appreciate a response on whether this is true. I don't want to troubleshoot a design limitation.

[G-Man]

The electrics on these bikes was a bit borderline with no proper regulation. The alternator and charge control were basically a copy of the Lucas systems of the 50s and early 60s.

The alternator (particularly the rotor) is now 50 years old and it won't have got better with time. Clean connections, a modern regulator-rectifier and LED bulbs will help your situation.

http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm


G

[LOUD MOUSE]

May I ask if you have checked if your bike requires the light on as it in many states is grandfathered to not require that.
My 25 cents worth.
The system as designed and used in the 60's when these bikes were designed and ridden (myself and friends) was satisfactory for daily use without the light system on.
Weren't required to have the lights on during daylight so we obviously didn't have a problem.
Figure most of us rode these bikes daily if not weekly so the battery was pretty much full charge.
Today I find that folks restore/rebuild these bikes and ride once in a while without keeping a charge in the battery.
The system is designed to maintain voltage but not charge a dead/low battery.
Keep that last in mind and you may not have problems. .............lm

I bought a 1966 CB77 I plan to restore. The previous owner said that if you run with the headlight on all the time as required in Washington state that the battery will go dead. I don't remember this being a problem way back when so would appreciate a response on whether this is true. I don't want to troubleshoot a design limitation.

[DJM]

I ride both a '64 CB77 and a '65 CL77 regularly here in the UK often covering a hundred plus miles in a day and sometimes up to twice that. For safety reasons I ALWAYS ride the bikes with the (standard 35watt) headlight switched ON and in addition both bikes are fitted with flashing direction indicators using 21 watt conventional bulbs. NOT LEDs.

Both bikes use original 50 year old alternators and I've never had a problem with batteries going flat, one bike uses a 'modern' solid state rectifier, the other an original metal plate job. Other than making sure the batteries are in good condition and that all the connections are clean and secure I've done nothing with either of the charging system which have both been totally trouble free.

I am doing decent runs at reasonable speeds and admit that if the bike was being used mostly for low speed runs in heavy town traffic the same might not be true.

Final point though, if the original systems were so poor why did Honda see the need to introduce a 'Low Output' version on later bikes to prevent the batteries being overcharged??

[G-Man]

Yes - Motorcycle electrics have always been a bit of a lottery - they seem to work well for some and not for others. I did 14,000 miles in the first year on my 1978 Honda CB400F. That had a 'proper' charging system with field control of the alternator and a three-phase rectufier.

It too had the traditional Honda 35/35 headlight bulb with a desperately poor reflector which was nowhere near good enough for fast night-time riding on British roads. I fitted a 60 watt assymetric-dip Hella headlamp which illuminated the road much better but the Honda three-phase rectifier died and took the battery with it. With the help of a friend we wired in a Lucas rectifier at less than 1/3 the price of the Honda version. That part was on the bike when I laid it up in 1982

Conversely, my Matchless 350 had a much-maligned Lucas 6v system very similar to the kit fitted to early Hondas. The big Lucas headlap worked superbly and was often mistaken fro a 12v unit.

I even managed to convert a 1950s BSA Bantam to 12v and discovered that the 'horrible' Wipac alternator was quite happy to push out 12v, power some decent bulbs and charge a battery through a modern rectifier and Zener diode charge control similar to the modern Podronice units.



My replacement for the CB400F had excellent Bosch electrics and 280watt alternator which took a Cibie headlamp upgrade in its stride with no fuss.

If you do happen to suffer with disappointing electrics there are plenty of solutions available these days. I have had a tutorial from an expert on re-magnetising alternator rotors which I am going to have a go at sometime.....


G

[ramwing7]

I was reading in some blog, somewhere that you could: " ..... bypass the dimmer switch and connect the white and yellow wires together at the rectifier giving full
charging all the time. This is only a good idea if you ride with the headlight on all the time."

This sounds like a solution to a bad dimmer switch, but I'm not clear on what connecting the white and yellow means. Do you use a jumper to connect the two, or do you splice the white into the yellow, or the yellow into the white? Do you leave them connected to the rectifier or what?

Thinking about doing this since my dinner switch is pretty questionable.
Anybody have any suggestions?

[DianneB]

The biggest problem with bikes of this vintage is the selenium rectifier. They were poor back in the day but is about all they had. They also don't age well. If you replace the selenium rectifier with a silicon rectifier/regulator you will see a HUGE improvement in electrical performance. They are maintenance-free, don't deteriorate, and will last for more years that you will! ;)

http://www.ebay.ca/itm/like/332118916822?chn=ps

They are small and will easily fit in place of the selenium rectifier.

(Don't use a silicon rectifier along - you will boil your battery.)