Hello

Just picked up a 1969 CT175 this weekend. The previous owner claimed that they had it serviced and running good 2 years ago and then had it "pickled" so it could be stored until now. When I got it there wasn't a battery. I had a 6v battery from another bike and I was eager to see if I could get a spark. It wasn't obvious where to hook up the battery, so I pulled the wiring diagram and traced the wires from the fuse with my multimeter. I found that the end of the wire going out to the fuse was plugged into a red/white wire with a female bullet connector. I unplugged it and connected it to the positive terminal on the battery. I was able to get the horn to work. However, no spark. Thinking maybe the red/white wire needed to also be connected, I ran some jumper wires so it was connected as before but this time with the battery. The wires were heating up so I unplugged it imediatley. Obviously the battery was not supposed to be connected to this line. So my question is 2 fold - 1) what is the red/white wire for? It just goes to nothing on the wiring diagram (is it ok to leave unconnected?) and 2) does this have anything to do with me not getting spark or is that unrelated? Also if it is unrelated, where is the next place to go to troubleshoot the no spark issue?

 

Good old CT1's don't need a battery, has magneto ignition.
First thought is clean the points. I'd just fold a piece of 'not coarse' emery paper & squash it flat at the fold.
Then via the flywheel slot just get it in there & back n forth a few wipes & i can hear it running from here.
Only one note is without a battery you'll likely blow the bulbs if you have lights 'on' & rev it above idle.
Otherwise lights off & neutral bulb might suffer but thats about all.
Best of luck, & pics if possible via an external source to link.
Cheers from NZ downunder. I have the first AT1 kick start model albeit now with a 175 top end.

Just to edit--red/white wires has me confused [old & confused] as can't think where that is.
White then Red are in & out of the rectifier by memory--not sure.
Unles is stator related charge wire & you powered up the lighting coil as a resistance which would heat up the wire & sounds like you bypassed the fuse so no fuse to blow although i'm not great at electrics & just look for the smoke--"there it is".
Maybe a lighting coil wouldn't produce enough resistance to blow a fuse--not sure. Don't follow me i'm lost haha.

Yes, no battery for spark but do not use any lights and rev it if you get it running without a battery as you'll likely blow bulbs.

Near the battery there are two wires with female red bullet connectors and one wire with a male connector. The stock fuse holder connects to the females (still available from Yamaha) and the male goes to battery.

I guess this is the diagram you're using or found one similar. Says "71 but unlikely to change as still early piston port model.
yamaha-enduros.com/index.php/wiring-diag...ct1-c-wiring-diagram
Maybe no neutral light on those.

A 1969 US model might be wired like yours in NZ RT325, taillight not run off battery here until sometime in 1970. 

Thanks everyone for the quick replies! The wiring diagram I am using is out of the service manual in the tech library that is for AT1-CT1s.

AT1/CT1 Service Manual

The diagram with CT1A at the top shows the red/white wire going to nothing.

I didn't realize I could get spark without the battery. I have a 1975 DT125 and it has to have the battery to get spark.

I will try to clean the points and see where that takes me. I did order a new battery - should see it in a week. I'll probably use the other one I have to try to prevent blowing bulbs as mentioned earlier.

Thanks again!


 

There is no "red/white" in that diagram or on the CT1 that I ever remember seeing. 

The diagram shows a "white/red" coming out of the stator.  Do not connect that to the battery or anything else!  Hopefully you didn't damage anything in the charging system if it was the white/red you connected to.   The white/red wire is an alternate battery charging wire and is described on page 129 of the manual. 

Thanks Mark! You are correct, I was referring to the white/red wire coming from the magneto. Thanks for pointing out that section in the manual. I also hope I didn't fry anything! I guess it is worth noting that I checked for spark before hooking the battery to that line. I didn't get spark and since the previous owner had the red wire that should go to the battery hooked up to this line, I thought maybe it needed power before doing any research. I guess after disconnecting the battery someone saw a male red wire and a female white/red wire and thought they needed to be plugged in.

I'll add to my post once I get it running again. Thanks!

You probably would not have hurt the ignition at all.  It's the lighting coil that could have been damaged but as long as you didn't leave it connected too long, you're probably okay.  It's really a good idea to always use a fuse at the battery...  could save some very expensive damage.

Just FYI, in general Yamaha did not ever connect different color wires with bullet connectors.  First color is the main wire color and second is the stripe color.  Main wire color is generally the key to pay attention to.  A wire with only a red stripe will normally not have anything to do with a wire that has red as a main color.

One thing to be conscious of is that black wires can be ground OR can power the ignition.  Since someone has apparently been plugging in wires, another early step would be to connect the black (technically black/white, but sometimes solid black) out of the stator directly to the single little wire coming out of the ignition coil under the tank. Do not leave the harness wires connected, just a jumper between stator black/white and ignition coil.  This bypasses all the kill switches and possibility that someone connected a ground wire to the ignition circuit that will kill the spark.  You don't want to run the bike this way as there is no way to kill the spark, but it is a good troubleshooting step if cleaning the points doesn't work.

Oh, and don't "gap" the points.  On that model, the point gap is used to set the timing so changing the gap will change the timing.  If max gap opening is within spec range in manual, you should be ok

 

Thanks again Mark! Super valuable information!