JD 400 spark

enduro97 · Post by **enduro97** » Wed Feb 08, 2006 3:19 am

Hi, I am working on a JD 400 that I drove on my truck and brought home. There was no key so I pulled the ign. wires connector off the key switch and it started and ran. I got it home and shut it off with the kill switch. Now the only way I get spark to both cylinders is with the key on or off and the kill switch in the kill position. No matter what I do #1 always has spark but #2 only has spark with the kill switch in the kill position. The sled doesn't start now like this only both plugs are working and it is getting fuel. Is the kill switch not allowing the motor to start? I also unplugged all connectors; key switch, kill switch and motor connector and still I only get spark on #1 cylinder until I plug in the kill swich, pushed in to the kill position. Any ideas, Thanks, Don.

400brian · Post by **400brian** » Wed Feb 08, 2006 3:26 am

If you unplug the main connector down by the pull start, you take all the wiring out of the loop. The kill switch should have no effect then, if fact, there should be no way to electrically kill he engine.

JDFanPa · Post by **JDFanPa** » Wed Feb 08, 2006 1:24 pm

like Brian said unplug it at the motor and that eliminates all switchs and both plugs should have spark let us know if this helps

enduro97 · Post by **enduro97** » Wed Feb 08, 2006 1:31 pm

Hi, I just tried the sled again, The only time I get spark in both cylinders is with the main wiring harness plugged in, the key can be on or off and the kill switch plugged in in the "kill" position. With the kill switch in the normal position, I loose spark in cylinder #2. I bought this sled out of a boneyard and got it running and have ridden this sled before. It has always started good and ran good but I just got it back after it sat at a friends house for a year+ uncovered and he never ran it. I have owned JD sleds for 30+ years but I haven't run across this before. The only thing I can think of is somehow #2 gets some feed from#1 in the kill position? The wiring looks complete but could there be a bare wire somewhere that would cause this to happen? Like I said before, I drove this on to my truck and drove it into the garage and shut it off with the kill switch. Now, ? I plan to go to the great eastern whiteout this sat. so I probally won't work on this one anymore 'til next week. Any more ideas? Thanks, Don.

JDFanPa · Post by **JDFanPa** » Wed Feb 08, 2006 2:59 pm

might be that aliens got your sled...............seriously its odd but somewhere along the way a switch is probably jazzed up from being in the weather but if your only getting spark at 1 cyl with motor connector unplugged you have to have a point thats dirty or a chewed through wire maybe

enduro97 · Post by **enduro97** » Thu Feb 09, 2006 1:08 am

I am beginning to wonder if I got the key switch wire connecter back on right when I reached up under the dash to plug it back in.....I'll have to check it out! I'll let you all know if I get this figured out, Thanks, Don.

Deleted User · Post by **Deleted User** » Sat Jun 10, 2006 2:56 pm

There are five wires that go to the ignition switch in the following arrangement (ignore the underscores, there to make it align properly):

___S_L
M_____
___B_G

I have labeled them according to a diagram of a replacement switch I have seen on-line somewhere as follows: (although what they actually do is my interpretation):
S = Start, goes to starter and I assume momentarily connects to Battery for starting
L = Lights, I assume connects to Battery when you want just light on assuming you have a battery.
M = Magneto, connects to side 1 of kill switch and ignition coil with red lead
B = Battery, connect to the + side of battery thru circuit breaker
G = Ground, according to the wiring diagram I have, this does not actually connect to ground but to side 2 of the kill switch and igintion coil with white lead.

This means to me that the kill switch (and ignition switch in the off postion) actually shorts out the two ignition coils (on the low voltage side).

So here's my theory:
1. Your ignition switch is not connected or doesn't work
2. Your kill switch is bringing your good spark to the other cylinder because there is an open circuit on your ignition generating coil (next to the condenser and breakers) on the bad cylinder.

The wiring diagram says 1974 for 400 and 500s S/N 11,001-20,000 (and 600, JDX4, JDX8 S/N 25,500-20,000?) if that helps.

harleysportster · Post by **harleysportster** » Sun Jun 11, 2006 8:54 am

enduro97,
Tell us what type of ignition is on the engine. The later 400 has CDI. As Brian and Andy have mentioned earlier, you should have spark when the main wire harness from the sled is unplugged at the engine. The kill switch / ignition switch turn off the engine by grounding out the ignition. With a properly working igniton, both cylinders will have spark when the main wire harness is unplugged. If your 400 has a CDI system, check this out and follow the diagnostic procedure.
http://s12.invisionfree.com/jdsleds/index.php?showtopic=491

JDFanPa · Post by **JDFanPa** » Sun Jun 11, 2006 1:03 pm

Harley dont think we will hear from Enduro he posted this in Febuary. I was excited at first when I saw the topic like cool something new then I saw my name on it already so I knew it must be old.

harleysportster · Post by **harleysportster** » Sun Jun 11, 2006 6:50 pm

Andy,
I missed the posting of the date. O-well, he doesn't know what he is missing.

JDFanPa · Post by **JDFanPa** » Mon Jun 12, 2006 2:02 am

yeah if I didnt see my name probably would have answered myself this time of year stinks for sledders

enduro97 · Post by **enduro97** » Fri Jul 14, 2006 1:51 am

Hey Guys, Sorry about not getting back here sooner. I never receiced the notifications from the post and totally forgot about checking back. I also have had some computer problems. Anyway, I don't want to say this but I gave up on this one and sold it! But the good news is I picked up a '76 340 cyclone the very same day! I may be looking for parts for this sled as it has sat for a long time. ( last reg. 1977! ) I have some parts but will most likely need more. So far I freed up the motor and cut off what was left of the full cleated track? I am cleaning the carb. and gas tank and going over the whole sled to see what it will need. I know 1 coil and the ign. box are missing and so is everything in the chaincase. I am hoping to find some used parts as $ is tight right now. I have a parts 340 liquifire that will donate some parts and will know more as I continue to check it over. Again, sorry I didn't get back sooner. Don. "Nothing runs like a Deere!"

Rodimus Prime · Post by **Rodimus Prime** » Thu Aug 17, 2006 3:45 am

well i have run into the problem you had and yes its feeding power from 1 cylinder to 2 as to kill the engine on these both coil supply leads are connected. this means that when #1 fires it should ground to #2 and vice versa.. all it is is dirty points plain and simple.

good luck with the 340 cyclone hope you have fun.

Brad Gyde · Post by **Brad Gyde** » Thu Sep 14, 2006 9:59 pm

I have many used parts for 76-78 Cyclones and Liquifires (in process of parting a 1977 Liquifire now). Feel free to e mail or call (I only check e mail normally once a week, normally weekends)

Have lots of parts for X's and 00's, Trailfires, and some Spitfire parts, but inventory changes a lot as I bring in more sleds all the time.

Hope I can be of help