Friday, October 12, 2012

Charging Sytem Upgrades

Given that my charging system appears to have problems now, as I fix it I might as well upgrade it a bit. Apparently these bikes have always had a charging system that was barely adequate. And that was in 1971, before bikers ran their headlights all day. And on a bike that didn't come with turn signals (which I have added). So, I decided to do these two mods:

headlight switch bypass mod: http://www.hondatwins.net/forum/viewtopic.php?f=53&t=6185
regulator/rectifier mod: http://www.hondatwins.net/forum/viewtopic.php?f=46&t=14530

The first of the 2, on my bike, will only help when the headlight is off. That should be pretty much never. But I can see turning it off to try and limp home if I have another charge issue.

The second mod allows me to replace the existing regulator and rectifier on my bike with a single combined rectifier/regulator unit. Here are the old bits:

The stock voltage regulator
The stock rectifier. I dissembled it to get the wires out, I intend to reuse the pigtail.

I replaced both of the units above with this new combined unit (front and rear view):


I modified the pigtail like so:

Here is the modified pigtail attached to the new unit:

And here it is attached to the bike (where the old rectifier was mounted):

Unfortunately I cannot yet report on how it works. It appears as though I may have killed my new battery by discharging it too many times. I am going to try and top it off and see if it works. But if not, I will have to get a new battery and then test this mod.

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5 comments:

  1. UnknownJuly 30, 2014 at 10:05 AM

    Did this work? I have a 1972 SL 350 That is not charging.

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  2. HeisenbergAugust 4, 2014 at 9:21 AM

    Hey Thomas, sorry for the delay. I'll say that it sort of worked. It can't overcome a weak stator. If your charging system, at its source, just doesn't put out enough juice, this won't fix it. However, this is less wasteful in transforming the stator output to DC. It did result in a nice clean 14.4V. But, and here is the catch, and why it is dependent on the stator, I only got that voltage at close to 3K RPM and above. So, for cruising on a rural highway, problem solved. For sitting at lights all afternoon in town, a slow drain still occcurred. It was much better than before, but I still put the bike on the trickle charger at the end of the day.

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  3. UnknownAugust 4, 2014 at 1:54 PM

    Thanks, I will have to try it out. Mine just stopped charging one day. Lasts about 15min on battery charge. I did replace the battery and same thing. I am not much of an electrical guy. Thanks again.

    ReplyDelete
  4. UnknownSeptember 22, 2014 at 5:50 PM

    One more question, How about wiring? Just plug into rectifier and be done? What about voltage regulator wires? Just leave empty?

    ReplyDelete
  5. HeisenbergSeptember 23, 2014 at 9:59 AM

    Hey Thomas. See the above pics for details of how I adapted the original rectifier plug to fit the new, solid-state, regulator/rectifier unit. Regarding the old regulator wires, as I recall I just taped them off. The link that I posted at the top of this thread confirms this.

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