Honda ZB50 Restore / Need Help

[Mel_Macallan]

Hi Guys,

I'm new in this forum and really hoping to find some help here.
Just a little info about myself ; While I was living in Hawaii, I worked on a bunch of scooters (just as a hobby), so I have basic knowledge of that. Besides that, I own a Honda Shadow 750 and a two Sportster 1200, but usually don't have to do more than regular maintenance on them. So that's that 😉

My father recently picked up this 1988 ZB50. For at least past 10 years or so, it was wasting away in some dirty backyard.

After he picked it up, he added some new oil and surprise - it ran. But only for about 2 min then it died. Afterwards he tried again but nothing.

Like mentioned, after 10 years laying around outdoors it was in a miserable condition. The garage in our neighbourhood didn't even consider to touching it. They took one look at it and turned my father away.
So I wanted to help and promised my dad to try 'n fix it, not knowing what I'm getting myself into LOL

Of course my first plan was to do the simple maintenance things, like clean carb etc but that didn't do it. The bike was dead, so I started to look closer and the closer I looked the more I realized in how bad of a shape that poor little bike was.

The must have went through a few crashes. There is no more key switch, and also no kill switch (no switch on right handlebar at all). There was no battery, but its kickstart only, so that's ok I guess. The kickstart was stripped, and engine full dirt, gunk and even tiny metal gravel. I ended up taking the whole thing apart cleaning every single piece and replacing some of them too.
I checked the electrical harness, repaired it as good as I could.
I got a battery for it and now the lights are all working, I checked all the ground wires and got a new Key-switch. Still there is NO Kill-switch, so I bypassed it and now everything runs through the Key-switch.

I put everything back togher yesterday, but still nothing. Engine doesn't to turn over - No spark. 😭
Its been over month now, but can't get it to run.

I went to a garage yesterday and the guy was real nice and gave me some advise. He suggested to take off the plug of ignition coil cable (where spark plug attaches to, and hold it directly to the engine(ground) to check for spark.
I did this today - no spark.
So my conclusion for now is, that it might be faulty stator (attached some photos). I did try to clean it up (so it doesn't look as bad as in the pic, but just cause it looks clean doesn't mean its in better shape I guess 🤓)

Anyone here got any experience with this bike? I would do a test with multimeter on the stator but as I don't have the service manual of the ZB50 I don't know what the correct reading should be.
Any constructive help / advise would be appreciated!
https://i92.photobucket.com/albums/l9/melaniechy/20200316_114413.jpg[img]https://i92.photobucket.com/albums/l9/melaniechy/20200316_114413.jpg
[img][URL=https://s92.photobucket.com/user/melaniechy/media/20200402_150644.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200402_150644.jpg
[img][URL=https://s92.photobucket.com/user/melaniechy/media/20200429_134954.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200429_134954.jpg[img][URL=https://s92.photobucket.com/user/melaniechy/media/20200429_135116-1.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200429_135116-1.jpg[img][URL=https://s92.photobucket.com/user/melaniechy/media/20200429_135125-1.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200429_135125-1.jpg[img][URL=https://s92.photobucket.com/user/melaniechy/media/20200429_135138.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200429_135138.jpg
[/img][img][URL=https://s92.photobucket.com/user/melaniechy/media/20200429_135147.jpg.html]https://i92.photobucket.com/albums/l9/melaniechy/20200429_135147.jpg[URL=https://s92.photobucket.com/user/melaniechy/media/20200403_180455.jpg.html][IMG]https://i92.photobucket.com/albums/l9/melaniechy/20200403_180455.jpg

[stinkwheel]

Have you fitted a new spark plug? (if not, do this first)

Does it have points or electronic ignition?

If points, file the surface of them, set the gap and consider replacing the condenser.

In any case, they are very simple ignition systems so it shouldn't take a lot of troubleshooting.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Riejufixing]

[Riejufixing]

[Mel_Macallan]

[Mel_Macallan]

[Mel_Macallan]

[stinkwheel]

Ok. If it has a CDI, that means it's electronic ignition.

Found a wiring diagram.

Forget about the lights. They are nothing to do with the ignition system. There are 5 wires attached to the CDI and these are what makes the bike run.

So get yourself a multimeter and set it to measure resistance (ohms).

Find the connector block that attaches to the CDI and disconnect it. Connect one probe of the meter to a piece of bare, shiny metal on the engine (the engine is used as an earth connection, a bolt head is fine, you may need to sand any corrosion off so it makes a good electrical contact). With the other proble, check the following wires that are attached to the bike side of that connector block (not the CDI side):

Green: This is the earth. Should read a very low resistance, similar to if you touched the two wires on the meter together.

Black with white stripe: This is the engine kill. Should read a very high (as in no reading, like the meter isn't connected to anything) resistance. With the kill switch pressed, this should change to a very low resistance.

Black with red stripe: This is the ignition power supply coil from the stator. This should read a resistance of between 50-300 ohms.

Blue with yellow stripe: This is the ignition pulse coil. It should read a resistance of 10-100 ohms.

Black with yellow stripe: This is connected to the ignition coil primary winding. It should read a resistance of 0.16-0.2 ohms.

One further test is the igintion coil secondary winding. Measure between the metal inside the sparkplug cap and bare metal on the frame. Should be 3700 to 4500 ohms.

If any of these are incorrect, it means there is either a fault with the componant you are testing or the wiring between where you are testing and the componant. Report back with your findings. If they are all correct, it should make a spark.

If they are all correct and you have a new plug fitted but it still isn't making a spark, I'd suspect the CDI may be faulty. These are trickier to test.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[stinkwheel]

[Mel_Macallan]

[Riejufixing]

[Riejufixing]

[Mel_Macallan]

[stinkwheel]

I found it online but it's the same as this CT70 diagram. Pretty much all small hondas of this age have the same wire colours and setup. It's the same as my H100 one too which is where I got the readings.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Mel_Macallan]

just added some photos of the bike to my post 👍😃

[stinkwheel]

[Mel_Macallan]

[stinkwheel]

I wouldn't necessarily call that fried to be fair. Ignition power coil resistance is on the high side but not out of the ballpark.

Usually if a winding has gone you get either internal shorts and so a reduced resistance or a broken wire and open circuit.

It's all very "agricultural" in there and your extra resistance may well be down to increased resistance in old, mucky connectors and earthing.

There is never any power in the ignition circuit unless the engine is spinning, it "self excites" by taking power direct from a seperate coil on the stator (which is the one you just tested). The battery is only working the lighting and has nothing at all to do with the ignition. It's possible you may get a voltage reading if you test between the black/red wire and the green wire and kick the bike over. It'll be a "dirty" and very short reading so I'd set the meter to measure AC volts. May not react quickly enough to show up on a digital meter though. I'd expect needle deflection on an analogue one.

Ignition switch is working.

Pulse coil resistance seems a tad on the high side, But again, a similar mode of failure as with a stator coil. It's probably worth checking the connectors for corrosion.

The pulse coil does need to send a pulse too, maybe worth checking the gap between the pulse coil and the rotor is reasonable (although from memory, it's non-adjustable).

Just noticed there is a coil earth connection, make sure this is in good order too.

Odd you are getting an open circuit with the plug in. Are you testing through the central electrode? If that reading is "real" it suggests either the plug is duff OR it's not making proper contact in the plug cap. it may be worth replacing the plug cap anyway (or as a temporary measure, just connecting the HT lead directly to the plug with a ring terminal).

Umm. You might be looking at a CDI failure. Don't panic though, they are common to lots of small hondas and you can get cheap pattern ones.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Riejufixing]

You can check the coil. Disconnect the low tension lead from it. Connect up your HT & plug and let the plug rest on the engine/frame where you can see it. Take a wire from the non-earth side of the battery, and quickly brush it against the coil's LT connector (you don't want to just connect it, you want momentary contact only!). The plug should spark.

[Mel_Macallan]

[Mel_Macallan]

[Riejufixing]

[stinkwheel]

[Mel_Macallan]

"Connect up your HT & plug and let the plug rest on the engine/frame where you can see it."
Do you mean connect the spark plug and then brush the "hot" wire against the tip of the spark plug?[/quote]
No. Your coil is earthed to the frame. The HT lead goes from the coil's HT contact to the plug cap connected to the plug top thence to the plug tip, and the plug rests on the frame or engine, so that when the coil fires, the spark jumps the plug gap (25 thou or whatever) making the HT circuit back to the coil's earth...[/quote]

Great advise! Will give it a go! Hopefully won't electrocute myself LOL

[Mel_Macallan]