Electrical issue. It's not there

Discussion in 'Tech Area' started by 1971CT70, Jan 8, 2019.

  1. 1971CT70

    1971CT70 New Member

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    I am digging your forum here. My first post.
    Hello all.
    I have been wanting to get a Honda CT70 for a while. I found one at a good price and bought it right before Christmas. Partial restoration. It runs pretty good. Its a 1971 Ko I believe. The guy I bought it from told me all it needed was a battery and the electric would work. I should have known better. A new battery charged up, but nothing in the way of accessories work. It does run, and the key turns it off. No lights or horn. I wasn't getting a charging voltage, so I got a new rectifier. I am measuring about 7.6 volts at idle now, so I think it is charging. I got a-hold of a schematic. It looks to me like everything goes through the key switch. So maybe its time to pull all that out and start looking for voltage there. I think it pushes in, after the tank and all are removed. Is there something that holds it in on the inside of the frame? The other thing I thought about is testing the lights and horn with a 6 volt supply (battery) to see if they are good. Any thoughts or suggestions?
    I need a new kick start seal, as oil is dripping. I want to change the seat and wheel rims, as the previous owner has them orange, likely to improve visibility, but I'd like to keep it original.
    Its a lot of fun to cruise around the yard in, with an occasional trip down the dirt road where I got it up to like 38 mph. (3 speed auto). I want to get all the electric stuff working and safe before I buy insurance and tag it, but I am concerned about where to drive it as I don't want to get creamed on a hi-way due to going too slow. Maybe just cruising on some trails is a better plan.:)
     
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  3. racerx

    racerx Administrator
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    Congrats on your acquisition.

    First advice, slow down...take this one issue at a time, do a little digging/homework, it's all mostly basic stuff. And, above all, have some clear goals in mind; from that point, the choices will almost dictate themselves. The toughest aspect of problem-solving, with these bikes, is the diagnosis; repairs rarely take a whole lot of expertise.

    For now:

    The keyswitch works, at least to kill the engine/allow it to run and you're getting adequate DC voltage out of the rectifier. Could be something as simple as a blown fuse, unplugged bullet connector, one broken lead...or rodent damage. Mice seem to love CT70 wiring...inside the frame. Worst case, a new wire harness is a $35 item. Good idea to use a 6v power source, like the battery, to test the system & bulbs. You can unplug the main connector from the engine, then feed battery power to the white lead (charging/DC circuit) then the yellow (HL AC circuit...normally only powered when the engine is running). If the bulbs are all good and there's no change, time to check the wire harness. The keyswitch is held in place by the chrome trim ring, surrounding the lock mechanism. It's best to use a proper spanner wrench, or socket, to prevent scarred parts.

    All of the engines oil seals can be replaced, while the engine is in place, they're cheap, too. Chances are the rims are fine, just need a repaint. Best bet is to glass bead blast them, along with the hubs and repaint them "cloud silver". New wheel bearings & brake shoes make a lot of sense, too...those items have been on the bike since the Nixon administration(!):eek:

    You might want to post some pix, especially of the seat & wheel assemblies. Get some educated opinions before making decisions in cash.

    Welcome aboard.:red70:
     
  4. lukelaw1

    lukelaw1 Active Member

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    I also bet that the lights are as simple as blown bulbs. Do you have a 2 position or 3 position key switch? 2 position is 1=off 2=run with lights. 3 position is 1=off, 2=run, and 3=run with lights. Possibly a wrong key switch position? Also if these bikes' key positions are set to run with lights with no battery or a battery that won't take charge the bulbs will blow. As far as the horn goes, try testing the horn on a 6volt battery. If it works possibly a problem at the horn button. The button just grounds the horn to make it come on. If the horn doesn't work on the battery try to adjust the little screw on front of the horn. The set screw controls the vibrating plates in the horn.
     
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  5. 1971CT70

    1971CT70 New Member

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    My key switch is a 3 position switch. I plan to start some troubleshooting with the wiring this weekend. Here are a few pics of my CT70. Thanks for your comments and suggestions. I love this forum already!
     

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  6. racerx

    racerx Administrator
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    Whoever made that seat cover didn't do a bad job with the stitchery. The patterning & color, OTOH...well...beauty is in the eye of the beholder, right?
    Anyway, if that's a reproduction seat, or based on a later model pan, you might do best by selling it and sourcing a new, reproduction, K0 seat. They won't have all of the OEM stamping detail but, they are available & cheap.

    If the wheel assemblies have been painted, a quick trip through a blasting cabinet should be all that's needed to prep them for painting. I'd chemically strip the brake plates, as they're supposed to be polished. Glass bead blasting them will greatly increase the amount of metalfinishing needed...before they can be polished.

    As for the electrical diagnoses, I'd start with the easiest stuff first...check the fuse, then try running a ground wire from the keyswitch face to a solid chassis ground. If that doesn't make anything work, time to start checking bulbs, either with battery power or a continuity tester. A broken filament can sometimes foll the eye. If all of the bulbs are intact and still nothing works, then it'd be time to pull the wire harness. FYI, it is possible to test every lead, with the wiring & switches left in-situ. It's just a lot easier to pull the wiring and test it on the bench (ask me how I know this). The most common locations for a broken lead are between the frame grommet & HL shell, followed by inside the tank area of the frame...if it's rodent damage.
     
  7. 1971CT70

    1971CT70 New Member

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    I did order a seat cover for a 1971, but it was too short from front to back by about 4-5". Because I bought it off ebay, i likely won't get a refund for my return. Live and learn. I am thinking about a complete new seat the next time. I'm thinking someone put a seat from a newer model CT on my 71. Aren't the longer? It does look hand stitched. I would like for it to say Honda, and look original. Any suggestions?
    I've never taken the wheels off a motorcycle or mini bike before. Been looking at youtube videos. Not sure of the condition of the shoes, but it stops the bike. I don't have immediate access to a blaster. Maybe I can pay someone or invest in one.
    As for electric. There's no telling whats inside the frame. I thought about a poor ground. Ran a wire from the battery negative to the frame. No help, but if the key switch needs to be grounded? Ahhhh...
    Thanks for your thoughts and ideas. I'll keep you guys posted...
     
  8. OLD CT

    OLD CT Well-Known Member

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    You are in luck... 3 hours and 7 mins on a ct70 ko aftermarket seat at a great price, right now. One bid. $60 plus 18 to ship. If I needed it, I would bid $85 at the last 10 seconds or less. Item #264115624449 . Type in ct70 ko aftermarket seat.
     
  9. kirrbby

    kirrbby Well-Known Member

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  10. airblazer

    airblazer Member

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    I’m thinking the previous owner was a Broncos fan o_O. It looks blue and orange to me anyway. It’s not hard to remove the wheels if you really want to...especially considering how clean it is. You won’t have to fight against grime and rust like most of us have. If it were me I’d get a lot of fun riding in before taking it out of commission to make cosmetic adjustments...that’s coming from someone who did the opposite and regrets it.
     
  11. 1971CT70

    1971CT70 New Member

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    If you mean the Denver Bronco, or Boise State, either are a long way from Alabama. I guess its possible. The previous owner said "give it a chance, it will grow on you". Said he traded a old Triumph for it. Besides the paint its got some new parts. New tires. I wish I knew exactly what has been updated. I hope to remove the tank, battery, and start looking at the wiring. I hope I can everything back like its supposed to go. I tried to ground the key switch but no luck. I am looking at a bad key switch, or perhaps a loose bullet connector.
     
  12. racerx

    racerx Administrator
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    These key switches rarely fail, unless damaged by a ham-fisted "mechanic". At this point, you might want to pull the rubber grommet from the frame and see if the keyswitch is actually connected to the main wire harness. Snagging the end of the tank and disconnecting the connector halves is not unheard of...and would result in working ignition w/inoperative lighting. The kill switch would not work...IOW there'd still be spark in the "off" position.


    From that stage and with verified bulbs, I'd check continuity between the engine ends of the harness leads (W,Y,ground) and their respective outputs (rectifier, HL feed) or pull the tank and wire harness from the bike..moving the diagnosis to the bench, where less back strain is involved.
     
  13. 1971CT70

    1971CT70 New Member

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    I spent some time going through some problems with my CT70 this weekend. I discovered the seal around the kick start shaft was there, but loose. I could turn it by hand. Removed the kick start from the shaft and drove it in, about flush with a socket. It should stop leaking now (I hope). Still dripping a little. Maybe it needs to get warm before it seals, otherwise I'll be ordering a new one to install.
    The electric is another issue. I removed the battery, gas tank, and key switch. I discovered there is a grommet across from the key switch. Once I took it out it gave me access. I don't think there is a problem with the switch. The problem is a poor ground. Its not there. I tried to run a clip lead from the negative side of the battery to various places on the frame with no success. Here is my question. In the original set up, where does the ground connect? At what point? I tried cleaning, sanding, scraping. So many of the bullet connectors are old and corroded. I can clean the male end, but not the female. I thought about replacing them. I thought about a new harness, but until I get a good ground I think Its a waste of time. Also the plug that plugs into the battery is old, and questionable. I'm thinking it needs to be replaced. I've included a few pics. Thanks
     

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  14. racerx

    racerx Administrator
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    First things first. Even if it's beyond over-obvious, have you checked the fuse? If the answer is "no" then do so before proceeding; if it's "yes", read on...

    The entire electrical system uses the engine & chassis as a ground bus...IOW, everything gets grounded to the chassis. The ground points are: battery (-), engine, wire harness, stator & keyswitch body.

    Seriously, this deep into the teardown stage, I'd pull the wire harness, unwrap any sections that appear to be less-than-perfect (if not the whole thing) and check every lead, focusing on those the supply DC + voltage. I'd also test keyswitch operation, using a continuity tester; that'll tell you if there's a problem...which there likely is NOT.

    You might be alright with that kickstart shaft seal. IMHO, the engine did you a favor by ejecting it. I'd have replaced it, just on the basis of age and the low cost ~$5. Not the end of the world if this one leaks, it'll just take more work to extract it, now.
     
  15. 1971CT70

    1971CT70 New Member

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    The fuse is good. Checked it first. Sorry I didn't relay that. I put one lead of my VOM on ohm scale to the negative on the battery, and the other lead to any place on the chassis and it reads open. Scratch and sand to bare shiny metal and touch with the probe, still open. I don't think I'm getting a proper ground connection. On a automobile (what I'm used to working on) the ground goes to the engine block. I need something similar for a motorbike. Got to dig a little deeper. Thanks for the assist!
     
  16. kirrbby

    kirrbby Well-Known Member

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    did you plug those greens together at the ignition switch?? then clean the switch, sand to bare metal on the inside of the frame, where the switch mounts, and install the switch in the frame. The battery- connects to the frame thru the green wire and the switch body.
     
  17. kirrbby

    kirrbby Well-Known Member

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  18. 1971CT70

    1971CT70 New Member

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    I'll do that
     
  19. cjpayne

    cjpayne Well-Known Member

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    Check your crankcase vent tube. It might be clogged. Thought maybe thats what caused the kicker seal to start coming out. I just use a piece of wire to check them.
     

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