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Post by crawdaddy on Nov 14, 2015 11:00:18 GMT -5
Hi everyone,
2008 Roketa MC-68A-150
The short story is: I have no spark. Going through testing I found I am getting around 50volts ac from the stator to the cdi on the black/red wire with the connection unplugged from the cdi box while cranking. When I plug the connector into the cdi that ac voltage drops to .8 while cranking. What would cause this?
The long story is: I have worked on this scooter for this guy a couple times. He brought it to me because it wouldn't turn over, or turn over fast enough or sometimes at all. I replaced the starter, started it up 3 times and it started fine. I pushed it to another spot and called him to come get it. He came the next morning and it wouldn't start. Here starts the no spark condition. I tested the stator unplugged at the bullet connectors and as above, on the black/red wire I get around 45-50 ac volts while cranking. I get .2 volts ac on the blue trigger wire. I have the black/white wire disconnected from the cdi connection. I'm sure I have some ohm results around here somewhere but wanted to get this topic started. I'll be glad to test whatever is required.
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Post by lain on Nov 14, 2015 11:53:55 GMT -5
If the only change is connecting the CDI then the obvious answer would be the CDI is bad now and may be grounding the connection inside of it. It happens over time they vibrate and they are just held together with epoxy which dries and cracks over time in extreme conditions like high heat or freezing cold temps. If it acts the same with a brand new CDI then I would expect the wiring somewhere to be frayed and grounding to the frame or something by accident.
CDI's are one of those weird components you can't test accurately and can cause a bunch of problems and seem like something else entirely. Inside the CDI is a green circuit board with a bunch of capacitors. A single capacitor could blow inside a CDI and it would still work until it reaches the RPM that capacitor is responsible for. It can also have a capacitor become disconnected from being hot for a while then becoming cool (hot cold cycles) eventually they break. The cheaper ones break fast, the expensive ones don't seem to break from these issues (like the gold Casoli CDI, def get one they are worth every penny and you save on money int he end because you will stop replacing CDI's lol).
When getting a new CDI match ti to the one already installed or get a nice one. Like I said Casoli is the best when it comes to CDI's, hands down, period, end of story. The Blue CDI with the pigtail connector are good but I find don't put up well with cold temperatures and cause kickback during starts. The orange CDI's that look like slightly smaller stock CDI's are just trash, they die so easily it's funny they can even still sell them. If in doubt of what to get stick with stock, stock is always good because it ran before with stock didn't it? lol
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Post by crawdaddy on Nov 14, 2015 12:14:56 GMT -5
Thanks much. This is on a brand new cdi and the 'old' cdi was only about 3 months old or so (I know because I replaced it for him). That is not to say they both aren't bad but I'm still leaning toward wiring. Strange that it would start one day but not even fire the next. I just ran out and took some ohm readings if this sheds any light-
with the cdi completely unplugged I'm getting 4mOhm on the green (ground) wire. 15kOhm on the blk/yl wire (to coil) 14kOhm on the red/white wire (trigger) and 59kOhm on the blk/red (ac power). All of them are showing continuity to ground - that doesn't seem right. When I unplug the blue wire and the black/red wire at the bullet connectors and ohm the wires to ground (forward towards the harness, not backwards towards the stator) the meter will never settle on a number but jumps from around .8 to .2 to 1. mOhm. I'm going to start pulling all the plastic off the front to check for a short but thought I would throw those numbers out there to see if anyone can help me narrow this down.
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Post by crawdaddy on Nov 18, 2015 20:21:22 GMT -5
Well, the new cdi came in today.....still no spark. I'm not a parts swapper but dang..... Just an update... I will start over tomorrow but again wanted any ideas...black/white wire unplugged so far as I know the 'stop' circuit should be disabled. Ignition has to be the problem. Weak stator? Does anyone have the pinouts for the start / kill switch for this scoot? I find generic diagrams but want to know things are plugged in right and the switches are doing what they are supposed to do.
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Post by lain on Nov 18, 2015 23:34:54 GMT -5
Well, the new cdi came in today.....still no spark. I'm not a parts swapper but dang..... Just an update... I will start over tomorrow but again wanted any ideas...black/white wire unplugged so far as I know the 'stop' circuit should be disabled. Ignition has to be the problem. Weak stator? Does anyone have the pinouts for the start / kill switch for this scoot? I find generic diagrams but want to know things are plugged in right and the switches are doing what they are supposed to do. Unplug the killswitch from behind the plastic around the handlebars to rule out the killswitch. Unplug the key switch from inside the front nose plastics and use the kickstarter or use a screwdriver to connect the large solenoid terminals (to use the electric starter without switches) to rule out the key ignition. |
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Post by tvnacman on Nov 20, 2015 7:07:17 GMT -5
if you have a harness from another scooter, separate the ignition coil, stator bullet connectors and cdi plugs. Unplug the coil stator bullet connectors and cdi. Connect the the harness you split see if it starts up.
John
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Post by crawdaddy on Nov 20, 2015 9:45:18 GMT -5
No change with all that unplugged. Still getting around 40 ac volts on the black/red wire into the cdi with the plug unplugged and it drops to a volt or 2 ac with the plug plugged in. Yesterday it was around 50vac and .7vac. I don't know why the voltages would change but the problem still remains.
side question - shouldn't removing the black/white wire from the cdi plug serve the same purpose of removing the switches and safety items from the system?
I'm at a loss. I don't know how a stator could fail like that but that is about all that is left......??
I wish I had another harness or another scooter around. What is sad is that a couple months ago I had this scooter's twin as a parts bike for another guy, finished his project and he sold that one for parts.
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Post by lain on Nov 20, 2015 13:21:26 GMT -5
No change with all that unplugged. Still getting around 40 ac volts on the black/red wire into the cdi with the plug unplugged and it drops to a volt or 2 ac with the plug plugged in. Yesterday it was around 50vac and .7vac. I don't know why the voltages would change but the problem still remains. side question - shouldn't removing the black/white wire from the cdi plug serve the same purpose of removing the switches and safety items from the system? I'm at a loss. I don't know how a stator could fail like that but that is about all that is left......?? I wish I had another harness or another scooter around. What is sad is that a couple months ago I had this scooter's twin as a parts bike for another guy, finished his project and he sold that one for parts. Yes removing the wire from the CDI would do the same thing, but if you don't have the extractor tool you will likely damage the terminal and plastic connector. The other way to go would be to cut the wire and put it back together later but then down the road it could loosen up and fall apart and leave you scratching your head and pushing it home. Much better to just disconnect them the proper way and not deal with it down the line. It really sounds like you have a bad CDI if the only thing making it drop is plugging in the CDI and removing it instantly restores the power issue... Did someone mess with your CDI connector and put the wires in the wrong places? Are you maybe grounding the wrong wire? It sounds like whenever your CDI is connected the power is grounded. |
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Post by crawdaddy on Nov 20, 2015 13:42:36 GMT -5
I agree, sounds like a bad cdi but 3 bad cdi's in a row? Possible I know but goodness. I've got the tool to remove the wires from the plug so that wasn't a problem. No one touched it from the time I called him to come get it to the time he tried to start it so no one messed with any wiring and it started right up before I left it for the night.
Right now I'm going out to run a dedicated ground to the plug for the cdi, go straight from stator to trigger wire and power wire to cdi with my own wires, bypassing the harness and leave the kill wire out. If it does the same thing I might throw a stator in it because I'm at a total loss.
I just can't get past that CDI is the common denominator
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Post by lain on Nov 20, 2015 14:52:03 GMT -5
I agree, sounds like a bad cdi but 3 bad cdi's in a row? Possible I know but goodness. I've got the tool to remove the wires from the plug so that wasn't a problem. No one touched it from the time I called him to come get it to the time he tried to start it so no one messed with any wiring and it started right up before I left it for the night. Right now I'm going out to run a dedicated ground to the plug for the cdi, go straight from stator to trigger wire and power wire to cdi with my own wires, bypassing the harness and leave the kill wire out. If it does the same thing I might throw a stator in it because I'm at a total loss. I just can't get past that CDI is the common denominator Remove ALL components except what you need to run (CDI, Solenoid, coil, battery, engine) to simplify it further. It may be something weird but who knows. Try to pull all the plastics off and view ever portion of the wire harness. If you have some extra terminals and some 16 and 10 gauge wiring rewire the entire running portion (look up in the text) with new wires and start it up by using a screwdriver to cross the terminals on the solenoid, and kill it by hooking the killswitch back up and switching it off, or unplug the black/yellow wire from the coil or unplug the CDI. The symptoms point to the CDI, but maybe the wiring to the CDI is bad or wrong? Did you cut the wrong green wire? When you cut the wire for the limiter it is right next to the wire for the ground. The bottom left wire in the harness when in the CDI is the limiter, the middle bottom one is the ground. If you ground the limiter wire instead it will also create these symptoms. |
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Post by crawdaddy on Nov 20, 2015 16:02:59 GMT -5
Agreed, problem is it ran fine then poof sudden no spark. No one touched it and it didn't leave my shop. I can see bad timing on a component failure but nothing as major as a rewiring gremlin that visited me during the night. I cut the harness to the cdi and ran green to a good ground, black/red straight to stator black/red (power), red/white to blue (trigger), left black white unplugged. I get the same darn symptoms, same results. Didn't touch black/yellow to coil but voltage isn't making it through the cdi to the coil so...... I took the harness out of the equation, made my own harness that I can see so I think that is what your suggestion was. No limiter was going to this cdi circuit so every wire and connection is accounted for and I get the same results. Acts like a cdi problem but really?  ?? I went to pull the flywheel and visually look at the stator but my puller wouldn't budge it. I ordered a different type......again, strangest thing I have ever seen. I appreciate hanging in there though and welcome the thoughts and ideas. |
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Post by tvnacman on Nov 21, 2015 7:23:21 GMT -5
Are you getting spark? Are you getting steady pulse?
Have you checked gap of pick up coil?
I don't think its your stator.
John
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Post by crawdaddy on Nov 21, 2015 10:21:00 GMT -5
still no spark. I'm getting .7 volts ac on the trigger wire and around 50 volts ac on the power wire UNTIL I plug in the power wire to the CDI. Good ground on green wire and black/white wire disconnected from the cdi plug.
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Post by tvnacman on Nov 21, 2015 10:23:59 GMT -5
Take the cdi and plug it in a running scooter. See what you get try all 3.
John
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Post by crawdaddy on Nov 21, 2015 12:05:17 GMT -5
If I was a shop I could swap stuff around all day and come up with some conclusion but alas i'm just a guy at home that people bring things to from time to time...That is a good idea though if I can find another scooter. I'll call the guy that owns the last one I worked on and see if I can borrow his.
I don't know if I would be happy or upset with 3 bad cdi units at this point.
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