I'm not the most mechanically inclined person so I need someone's help. Here's what happened with my '81 C70...
I ran out of gas last week while riding home from work. Switched it over to reserve, stopped by the nearest gas station, filled it with Premium (I like to baby my old girl) and got home with no problem. A couple days later I tried riding to work again and the engine was sputtering really bad - could barely get it up to speed to shift into 2nd gear and when I did it started to sputter out and die on me. I turned around, went home, and switched to the car - I chalked it up to bad gas. Fast forward to today and it's still sputtering so I added some Sta-Bil to the tank hoping that would help things out and had plans to drain the tank and refill it if that didn't work. After I had it running for a few minutes (still sputtering) I started noticing something smoking under the right-side cover. Took that off and after going through my owner's manual realized that it's the rectifier - it's very hot to the touch and the plastic seems to be a bit on the melty side (I assume that's what's causing it to smoke?).
From reading through some posts on the forum, I've learned that the rectifier is an electrical thing so I'm not sure how the sputtering could be related to it - I really thought it was a fuel thing. Could it be the rectifier? Is this something that might be fixed by just replacing it? Is there more going on here? My bike has been running like a champ for the past year and I'm very sad that it's not running right now.
Is this something that I can try to fix on my own or should I call my mechanic?
I really appreciate any advice. Thanks in advance
Jessica
--- In Honda-C70@yahoogroups.com, "Tom" <wynnjunk@...> wrote:
>
> I was reading this thread, and have somewhat similar issues. My battery has drained really quickly (< 1 year) and it must have had something to do with the Lifan 120cc I put in my 1983.
>
> 12V to 12V, so no voltage switcheroo.
>
> "Headlight, high beam indicator and dash light are all powered by AC directly
> from the engine's stator."
>
> OK, that makes sense because they all work. And the turn signals ONLY work when the engine is revving high. At mid-rev, they blink real quickly like a staccato beat.
>
> I replaced the rectifier with the one that came with the rest of the engine kit I bought from DrATV so I would have assumed everything went well. Horn also worked initially, but is now dead too.
>
> Should I test the new rectifier? I'm getting tired of using hand signals indicating that I'm turning!
>
> Cheers,
> Tom
>
>
>
> Finally Joe posted "If I short the posts on the starter solinoid with a
> screwdriver the bike starts up no problem."
>
> That proves the battery can discharge a hefty amount of current. That is a good
> sign.
>
> Whether you have a Voltmeter, test light, or multimeter with a diode test
> function, it is easy to test the rectifier. The 1982 Cub rectifier is a simple
> one-way valve.
>
> Test it like a fuse, then test it again by reversing the test leads. If the
> rectifier is GOOD, one test will pass like a good fuse... and one test will fail
> like a blown fuse.
>
> A BAD rectifier will either appear like a blown fuse in both tests, or will
> appear like a good fuse in both tests. I suspect your rectifier is shorted, so
> it will test like a good fuse in both directions. Toss it and replace all the
> bulbs. Put in a new fuse for good measure.
>
>
> --- In Honda-C70@yahoogroups.com, Joe Shuford <joeshuford@> wrote:
> >
> > Hey Guys. Well I think I have it licked. There was a bad ground in the horn button assembly and it was not visible. After disassembling the handle bar and straght wireing the horn I realized that it was in th button. I caved and went with the radio shack momentary switches and everything is working great!!!!! all lights, horn, starter etc. Thanks again for all of your help. I have now replaced the carb, run down the electrical and replaced the ignition and she runs really well. Your guidence has been invaluiable. Thanks again for ecverything.
> > Â
> > Joe
> >
> >
> > ________________________________
> > From: jpardue <inventorpardue@>
> > To: Honda-C70@yahoogroups.com
> > Sent: Saturday, May 5, 2012 11:06 AM
> > Subject: [Honda-C70] Re: Electrical Problems gone wild
> >
> >
> >
> > Â
> >
> > Joe said "Thanks so much for the response".
> >
> > You are most welcome, hopefully you get it fixed and roadworthy.
> >
> > Joe noted "Thee batteries were AGM and sized properly for the bike. They completely drained of all amps and would not recharge".
> >
> > Most rechargeable batteries are quickly destroyed by AV charging Voltage so that validates the rectifier is shorted.
> >
> > Joes added "I have inspected the horn, and turn signal switch and the on-off switch and starter button. All grounds have continuity. At this point the lights all work but when the flashers are on all lamps flash too. I may not have properly reassembled the switch module so I will double check that. The starter button worked at one point today but will not now and the battery is definately fully charged".
> >
> > Sounds like the Green ground wire in the handle bar area is NOT grounded. That wire could be broken inside the insulation where the handlebars rotate. One easy test is to run a 14 gauge wire from the battery ground terminal to the GREEN in the headlight bucket.
> >
> > Joe asked "Can the rectifier come a go like a bad ground?"
> >
> > The diode rectifier could possibly work and then not work, but a rectifier failure will not make your lights flash with the blinkers. You have two separate problems.
> >
> > Joe commented "I am going to upgrade the horn and the starter buttons with new momentary switchs from Radio shack".
> >
> > I recommend you fix the handlebar Green wire ground problem, and you may find the stock switches work just fine. If you disconnect the Light Green wire feeding the horn switch, and touch the horn side of that connection to ground with the ignition switch ON, the horn will sound (provided the horn works and its getting power from the switch). The test wire comes in handy here... connect to the ground terminal of the battery and then to the Light Green horn wire.
> >
> > Let us all know how it goes, be patient with it, ask questions...
> >
> > Jon Pardue
> > Sarasota, Florida
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
1970-73 C70 Honda Service Manual: http://tinyurl.com/6ebwtw
1970-73 C70 Troubleshooting Guide:
http://tinyurl.com/6ebwtw (scroll to sec.7.1 page 101.jpg)
1980-83 C70 Honda Service Manual: http://tinyurl.com/hu42c
1980-81 C70 Troubleshooting Guide:
http://tinyurl.com/hu42c (scroll to sec.18-1 page 170.jpg)
1982-83 C70 Troubleshooting Guide:
http://tinyurl.com/hu42c (scroll to sec. 20-28 page 205.jpg)
1980-81 C70 Maintenance Schedule: http://tinyurl.com/z4zn6
1982-83 C70 Maintenance Schedule: http://tinyurl.com/hw35c
More resources for C70 Passports and Cubs:
http://www.shlaes.com/Vehicles/Scooter.htm
http://www.velodrome.com/HondaC70/HondaC70.html
