Question-------------------------
Followup To
Question -
-------------------------
Followup To
Question -
I recently aquired a 1973 KX400 in almost mint condition for only a case of beer. I am having trouble getting spark. If I kick it over I can push the kill switch and get an arc across the sparkplug but it will not spark when kicking it over. I have traced the wiring and all other things I could think of. Any advice?
Answer -
Jeremy,
Wow, that's odd. Typically the kill switch DIRECTLY grounds the coil rendering it electrically dead. You should get current to the coil but none out. Sounds like you have a faulty switch. Remove the switch first and check for damage. If in doubt leave switch "open" while dismantled and try for spark again. The fact that you are getting spark at one point leads me to believe your ignition system is operating to some extent however it is very possible you need to clean, set and adjust the points or better yet, replace w/ a new set ALONG W/ A NEW CONDENSER. This should only run less than $20. Points are very failible and need to be reset or replaced at times. It is very possible your bike was left last with failing points. I highly reccomend you purchase the Clymer or Haynes manual for you model. Inside you will find explicit instructions on how to replace and set them. This is a detailed process and one I don't really have the time to get into in a short letter. If you run into problems, please feel free to contact me again.
Good luck,
Mike
Well it's me again, I may be wrong but 2 strokes have a magneto with pickups right. I don't think there is even a condenser or points like there would be in a 4 stroke. As far as the kill switch I can unhook it directly and it doesn't change a thing. I have checked and cleaned all contacts and coneections from tha ignition pickups to the sparkplug. I have to order a manual so I was hoping for A little strategy so I wouldn't have to buy a book for a one time use seeing my owner's manual is also a shop manual, yet is no help. Is there a way to test the cdi box, coil and magneto? I am kind of a pain in the rear huh? Over and out.
Answer -
Jeremy,
Try starting w/ the connections open and then closed at the switch. There may be one of 2 types of systems here, one w/ current stopped by grounding(closing the circuit) and the other by shorting the circuit (opening). Yes, there is a "true" magneto w/ actual non-electric magnets inside to excite the stator w/o the use of a battery to energize electromagnets however, there are a set of points and and a condenser. These are the only thing telling the current when to run to the coil and then plug. You do not have an electronic ignition like newer models (at least I'm 99% sure of this, Kawasaki made there H-1's and 2's in the mid-seventies w/ ahead of there time electronic ignitions but were not put on the trail and MX models of the same era). Both 4 strokes and 2 strokes at one time (and some 2 strokes still do) used points and condensers. Now the flawless elec. ignition modules are cost effective and are on just about any 2 and 4 stroke you can find from lawn mowers to Ferrari F-4's. There is no diff. between 2's and 4's when it comes to ignition, the 2's plugs just fire twice as often, every other stroke opposed to every 4th stroke.
Hope this help clear things up,
Mike
OK this is getting ridiculous. I must be asking the wrong question or something. I know what and how points are and work, My 1973 Kawasaki KX400 MX racing bike has A magneto, A cdi box and a coil. Behind the magneto is a set of pickup coils (my terminology maybe wrong here but you know what I mean), My kill switch is a push button type that runs off 1 wire which is a ground wire that comes from the wires that go into the coil. You can unplug the wire and it will be like not having a kill switch at all (because it works when you ground out). I have no spark, I can kick over the bike one time and push the kill switch and it will spark on the sparkplug one time. I can di this over and over. I have checked every wire and connection on the bike which only consists of three wires that come out of the magneto then go to the cdi box, after that they change colors and then run to the coil, at this point the black ground wire split and goes to the kill switch. After the coil the sparkplug wire goes to the sparkplug. I am not trying to be a dick or anything but you are supposed to be an expert on this kind of thing in this era and with Kawasaki's as well as yamaha's. So I think you don't know what I am talking about or I gave the wrong info off the bat or you are toying with me. All I am looking for Is a was to diagnose the problem. I believe it is in one of the components. I have repeatedly asked if there is a way to test any or all of the componenets like the magneto, cdi box, or coil. I am sorry to come off like this but it is starting to get frustrating. If nothing else maybe you can direct me to someone who could better answer my question. Thank you for your time and sorry to be a pain.
AnswerJeremy,
Sorry, I did a bit of searching and found that the KX does indeed run the igniter unit (CDI) that the H1 and 2's had. If you are getting a strong blue spark upon grounding your coil may be ok. This is not certain though. The only way to be sure is to test the primary (between the two low tension wires(small ones))and secondary (between the high tension lead/sparkplug wire and the small wire that goes to the stator/magneto) resistance readings of the coil. I don't have the specs for that particular model, you'll need to purchase the manual for that or seach online for the specs. Generally the primary is around 1.5 ohms and the secondary, 6.5 ohms. Something else comes to mind, you may be getting a spark only upon grounding by way of the kill switch because the coil itself does not have a strong ground at it's mountings possibly from rust, corrosion or looseness.
Other than this I'd have to suspect the CDI unit. I found someone quoting the manual online on testing the unit, here it is: "source" coil resistance( stator) BLACK and BLACK/RED resistance should be 270-330 ohms!
"Pick-up-coil" (trigger coil) WHITE/RED & BLACK resistance (ohms) should be in the 90-110 range.
I can't tell you how to exactly test the output of the magneto, generally you are looking for 12 volts +/- VAC before the ignition coil.
Sorry for the run around, I am do have a wealth of knowledge on 2's but this fact snuck by me. I highly suggest you pick up the manual for current and future reference, I saw quite a few for cheap while seaching online for you.
Best of luck,
Mike
