Hello all,
I'm new here, and still trying to get a feel for this site. Just purchased a Chinese blaster knock-off (Baja Extreme 150) and was quite happy with the bike until last week. One minute it would start right up, and the next it wouldn't. Coincidentally, this happened after I relocated my levers and kill switch apparatus.

I did check for juice at the small primary wire on the coil (using a test light), and there isn't any. I figured that its either something to do with the kill switch, or the CDI died. I am getting power at the cdi, at the black wire with the white (?) stripe--constantly. I also checked for juice at the kill switch contacts, and I have nothing, but I'm assuming these are negative anyway. I know that with breaker style systems, a good way to kill the ignition is to ground the negative side of the coil. Not sure about these cdi systems...or HEI for that matter.

So, what are your suspicions, besides the kill switch. I do have a new one on the way, by the way.

Thanks.

 

Moved to the Chinese quad section. Hope you can get some help. -Mod.

 

How many pins on your CDI? This is so I can post up the right test procedure.

Test lights are worthless. Throw that piece of junk away. Break it half before you do - that way no one else will be tempted to pull it out of the trash and try to use it.

Buy a meter. They are a cheap these days, and ironically, often cheaper than test lights. They tell you everything a test light will - and can tell you a *whole lot more*. How do you measure resistance with a test light? How do your measure current with a test light (AC and/or DC)? How do you measure 200 volts AC (but limited to a few tens of milliamps) coming from the stator with a test light? I hope you see my point...

You can get a really nice meter for about $20. At harbor freight you can get servicable meters (with battery) on sale for $2.99 if you watch their adds.

All those places you were trying to measure "juice" (other than the one wire) have complex low duty cycle AC waveforms on them. I woudn't expect a test light to reveal any relevant info at all.

Don't ground the ignition coil primary wire to kill spark. It's really hard on the CDI internal storage capacitor (the "C" in the acronym CDI), and the SCR switch. The peak currents are really high. Use the kill switch input (if you have one), or short the trigger signal from the stator, or a few other ways which I can list if it is relevant to the problem at hand.

 

Thanks. The bike did start today. It had a little trouble initially. It seems to be sputtering a little, especially when I gun it, but that could be because it needed to warm up.

Something else captured my attention. When it couldn't run before, I had power at what I think was the ac ignition wire. It's one of the two wires in the two pin harness clip..but not the kill switch wire.
I had power there before, even with the ignition switch off. Today, after it ran for a bit, I rechecked it for power, and this time it was off...as I think it should be.

So my suspicion is directed towards the rectifeir. What do you think? Something else I should add. When I first had problems, the starter wouldn't turn. This eventually led me to the battery, which I discovered had a loose connection (positive side). I was thinking that this loose connection may have thrown the rectifeir off, which then had an adverse effect on the CDI.

I'm not an electrician. I just use logic. How am I doing? Does my reasoning click with you?
By the way, I contacted Baja Motorsports to ask them if my bike is dc or ac, and I think they just told me anything get me off the phone. They told me it was dc, but after conducting a test using my meter, it was pumping out 45 volts at a very low idle (measured at the same ac ignition wire), which apparently indicates an ac system.

 

Thanks Lynn,
I thought I mentioned that it was a 6 pin CDI, but I apparently forgot to. If you'd read my last post, I did test the cdi using a multi-meter to find out if its a dc or ac unit.

The bike is still running, and the fact that I had current at that B/R wire (when it wouldn't run) presents a clue that the real problem lies elsewhere...rectifeir?

 

And again, I had power at that B/R wire even with the ignition switch off.

 

So by measuring "power" does that mean 12 volts DC? If so your CDI is DC powered. If you read all your posts you *almost* said that, but not quite. You stated you tested it, but didn't specify the outcome of that test .

But then you said you measured 45 volts (AC?) at very low idle. What? Where? If never written any procedure that measures AC voltage on the AC ignition power wire while the CDI is hooked up - which is must be hooked up if your engine is running.. I'm totally confused...

If your CDI is DC powered (please verify that), then it definately should not have 12 volts on it when the ignition switch is off and the engine is stopped. If you do have this wire powered all the time then I would suspect the ignition switch. The rectifier regulator can cause all kinds of problems, but it cannot provide 12 volts to a DC powered CDI with the engine stopped and the ignition switch off.

But why are you doing these crazy ill defined tests? Your logic does not make sense, and your terms (like I got power at this pin- whatever that means - AC, DC, how much? Measured how?) have no info in them. Could I respectfully request that you do the standard tried and true diagnostic tests and post your results so that we can review them?

After we get that info:

Number one: Is your CDI AC powered or DC powered? I don't know at all at this point.

Number two: Let's figure out this power issue where your CDI power pin (be it AC or DC - I have no idea at this point) is powered (whatever that means) all the time.

Number three: Your quad starts up and runs (albeit badly). So the ignition system works. I'm thinking that it is likely that its possitle all this electrical stuff is a giant red herring, completely due to measurement errors, and the problem lies elsewhere But doing the standard tests accurately and completley should shed some light on this.

 

I mentioned that it was reading 45 volts (or milli volts?) at the B/R wire. I should have been a little clearer on that wires circuit. I came across images you've posted indicating that wire to be the "ac ignition power". Its black with a red stripe (B/R), and its the only other wire in that clip along with the kill switch wire (B/W).

The fact that its putting out that much energy is what indicated to me that it is an AC CDI.

The problem, as Ive mentioned before, is that when it doesnt want to run, I have power at the above mentioned wire...even with the igntion switch off. When the bike does decide to run, I dont have power there.

This is why I suspect the rectifier.

 

Yikes...

If you went to the bank and asked them how much money was in your checking account, and the teller came back and said: "you have 45,000 dollars in there.. Oh wait, maybe it's just 45 dollars... I don't recall..." Well? You'd send that teller back to get the proper answer wouldn't you?

45 volts is 45,000 millivolts. That is a *huge* freaking difference!!! 45 volts is big, 45 millivolts (on the ignition power wire) is irrelevant noise.

You've got to stop taking these measurements so causally. It is *very* important that you get this right.

When you say there is either 45 millivolts or 45 volts then you might as well say I measured a big voltage or no voltage. There is no information here. Nada. Zip.

Energy is measured in joules. You need to be measuring voltage.

And I need to know what meter you are using and what the dials are set to. Where are you putting the probes? Are you measuring AC voltage, or DC voltage?

In order to help you measure stuff (and I think you really do need help with this) I need to see exactly what you are doing - step by step.

If you are claiming that you measure 45 volts AC at the CDI power pin with the engine stopped and the ignition switch off, then I will frankly say that that I don't believe you. This is absoulety impossible.

Based on current data, the rectifier is at the bottom of my list as a possible culprit.