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Motorcycle Repair/1964 Honda 305 Dream Charging System


Hi Bill,
My 1964 Honda 305 Dream fails to keep the battery up in city driving conditions.  I'm told its the rectifier unable to keep the battery up.  It puts out 13.4 volts at full rev but in city driving it won't keep the battery up.  Do you have a fix for this and if so can you give me the fix, or a recommended part number and where to find it.  Any help would be greatly, greatly appreciated. Thank you Bill.

Robert Trudeau

Robert, there are a lot of variables in these kinds of issues.....

First, I am glad to see that it is putting out 13.4 volts at full output. That eliminates the stator as part of the problem.

Second, there are some replacement silicone diode rectifiers that might enhance the charging system output...

The other option is to rig up a Radio Shack full wave bridge rectifier, which have great performance, but requires some modification of the bracket to mount it up to some kind of heat sink and connect to the existing wiring.

I would load test the battery to ensure that it is holding all the voltage that it receives. A weak cell can cause capacity load issues. The stock charging system only puts out about 1 amp, at least the later low output types. These are generally 1965 and later, so check your rotor to see if it has markings that are C72 (L) or just C72 which is the earlier higher output types that do about 2.8 amps, as I recall.

You must use the stock headlight wattage rating bulbs. OEM bulbs are 35/30 watt, but 35/35w may still work. I assume you are riding with the lights ON for safety. DO be sure that your brake light is not staying on when you are riding. The switch is adjustable and sometimes can get triggered by a light brake pedal motion while riding. If the brake light is staying ON, the system will fall behind after awhile. Good place to use an LED bulb, to reduce system current loss.

IF you are doing a lot of short trips... stop and go runs, then using the electric starter frequently and not driving long enough to replenish the battery will cause voltage loss after a few hours.

"Charlie's Place" has/had some solid state regulator rectifiers that might help overall performance of the charging system. He was out of stock for awhile, but may have them back available now.

Make sure all of your electrical connections are nice and tight with no corrosion present in the connectors. A good clean ground is important, as well.

Bill Silver  

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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