Posted: 03/01/2004 5:20:00 PM
What is the procedure on checking on the condition of a cdi unit on a '89 xr 600? thanks
Reply by Admin on 03/01/2004 5:58:19 PM
Here's an article that may be of interest: Testing for a Suspected CDI Problem
Reply by kubiak on 03/02/2004 08:45:02 AM
Reply by winind on 03/10/2004 10:05:34 AM
The CDI went out on my '93 xr650l. The symptoms were weird. The bike would run for ten minutes then suddenly quite. I would pull over, turn off the key for 5 minutes then it would run again. Sometimes it would backfire really loud.. I am talking like M80 firecracker loud!! KABOOM!!! And the spark was erratic. I discovered that with a spark tester. I also checked wiring harnesses and other electrical components until I finally determined it was a bad CDI. I used a process of elimination.
The Honda shop could not diagnose the problem, so I did the internet search and I found a site dedicated to fixing old Japanese CDI's.
CDI's can be very expensive or cheap. The local Seattle Honda shop quoted $265. I bought a new OE unit from internet Honda dealer for $110 w/free shipping and no tax.
Here is a quote from an electronics engineer who rebuilds CDI for older Japanese bikes:
Your page is very informative.
My 1993 Honda XR650L with 4,000 miles has intermittent or no spark. The bike is hard to start. Also when it does run, the engine dies after it warms up or if I rev the engine. With a spark tester plugged into the spark plug cap and grounded against the cylinder head, the engine cranks and the tester shows blue spark for about 1 second - then it goes dead. If I switch the ignition off then on again and crank the engine, the tester shows spark again for a very short time. Could this be a bad CDI ($110 for a new one)
I hate to just throw money at this, but I am getting desperate. Heck my friends won't ride with me anymore because my bike craps out!
The bike has been in storage for 5 years (indoors). The bike is in mint condition and the carburetor is cleaner than my wife's dishes. I tested the continuity of the wiring harness, checked and re-crimped the electrical connectors. I also checked the resistance of the ignition coil, spark plug cap, and pulse coil. Any ideas about what can be the problem? I am totally lost on this one; even the local Honda shop cannot find the problem. Best regards, Stephen
Reply by kubiak on 03/10/2004 7:36:37 PMStephen -
Thanks. Regarding your problem, truth is, most shops would just start with some basic tests and plug stuff in till it worked. More expensive for you, so:
A shop would test the Ohm / continuity of the sensors to see if they're in limits. But truth is, test means very little, and sensors may test good but not work or work VERY sporadically and fail after getting warm. SAME EXACT SYMPTOMS OF BAD CDI. The only difference is, very little TESTING of CDI can be done and I don't know anything about yours (except they're all pretty much the same).
- I you get spark at all, my gut feeling is that it is NOT the coil. They usually fail due to short (not intermittent). But they're cheap to replace if you get to wits end.
- If the spark dies at higher RPM or heat then I suspect the sensor or CDI. Now we talk Vegas odds. $110 for a CDI is cheap. I tend to start with that. If your wrong, doesn't hurt to have a spare (if you plan on
keeping the bike a while). If that's not it, then sensors are bad but they are harder to replace. so, again I tend to replace the CDI first. The symptoms you have can be EITHER!! So...
IN ORDER OF difficulty your problem sounds like:
- bad connection
- bad CDI
- bad sensor
- bad coil
when you talk about a sensor which one do you mean?thanks
Reply by Stu on 03/10/2004 11:05:21 PM
I had the same question, but I believe he means the timing pick up coil(s). BTW, those can be checked several ways;
- check the resistance with an ohm meter and make sure it's not shorted or open (should probably be around 100-300 ohms - manual might say or if you have two, make sure they're both about the same),
- a voltmeter on the output at a very low setting (lowest since the output will me milli-volts) set for AC volts and check for a voltage when cranked. In this case, since the output only happens when the engine is cranked, an analog voltmeter may be easier to read. You'll just see the number increase momentarily on a digital (DMM), but as long as you see voltage, it'll probably mean it's good.
- an oscilloscope which would show voltage and waveform.
Reply by kubiak on 03/11/2004 09:12:58 AM
is a pickup coil the same as the exciter coil?if it is i checked that already and it was right in the middle of the good range when hot, which was when i had trouble once in awhile. i adjusted my valves, they were a bit too tight and that stopped the sneezing at idle thing but the weird thing was i changed the plug and now it starts hot or cold perfect. the plug wasn't that old and it was a perfect tan color so i thought it was ok. i guess i could had just a defective plug.i should have started with just a plug change at first. i remember on my last '87 xr600 whenever it got hard to start i would put in a new plug and it would be good again.how does a plug partially foul when the bike is tuned good?i use the stock dpr8ea-9 ngk plug.
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