Motorcycle Repair: electrical, honda atc 200s, honda trx250

Question
hi i have a 86 Honda trx250 and when i go to start it it turns over but doesn't start, so i checked the spark and there is no spark so i changed it but still no spark. I no enough about car motors but i don't no much about these motors. So if u could help me out that would be great, thanks

Answer
Hi Matt,

I recommend that you get a copy of the repair manual for troubleshooting the problem.

You'll need to perform several tests using a multimeter to verify if the ignition and charging systems are working properly.

See the tech file below for more on testing. You'll need to perform similar checks.

Respectfully,
Mark Shively



No Spark Troubleshooting
1984 Honda ATC 200S

1. Spark plug; Use a "known" good plug. NGK DR8ES-L gapped to .024-.028in
2. Plug wire; Remove the entire plug wire from the engine/coil...Ohm out the plug wire and plug boot together Then wiggle the wire while you Ohm it. If at any time it reads "open"...repair it or replace (if good put it back on the coil).
3. Coil; Ohmmeter set on RX1.
........A. From the wire plug on the coil to the mounting flange...0.2-0.4
........b. From plug boot to the mounting flange...3-5K
........C. Ohm from the mounting flange to a bare spot on the frame. If it doesn’t Ohm out....clean the mounting area on the coil/frame
........D. Inspect the spade wire connection on the coil to make sure it is clean and tight.
4. Pulse Generator; Located under the cover marked CDI on the upper left side of the engine:
........A. Turn the engine over and make sure the rotor spins with the engine
........B. Disconnect the wires for the pulse generator and Ohm them (RX1) value is 20-30
........C. Inspect the rotor pickup end (steel part), if it is dirty clean it with #0000 steel wool.
5. Kill switch; Make sure it is in the "run" position. Remove the headlight and find the 2 wires for the kill switch. (green and black) they should Ohm out, wiggle all the wires to make sure it doesn’t change; then put the switch to off and it should Ohm open.
6. Alternator (stator). Unplug the wires.. Ohm the black (one going into the stator) wire to a good ground (wiggle the wire to make sure it doesn’t change....It should have some resistance if it is open...you have a broke wire. Do the same thing to the green wire. Pay close attention to where the wires go into the cover. I have seen a bunch that had broke wires going into the cover.
6. CDI unit;
...........Hold the CDI in your hand; looking into the plug; have the plug on the left.......there are 2 rows of 3 pins....top row from the left to right are 1-IGN 2-SW 3-EXT second row left to right.....4-PC 5-E1 6-E2
Like this
.......[ign][sw][ext]
.......[pc][e1][e2] While you are looking at it
Here are the test points

Positive test lead - negative test lead- value
SW-EXT-O.1-20K
SW-PC-0.5-200K
SW-E1-0.2-60K
SW-E2-0.2-60K
SW-IGN-infinity
EXT-SW-infinity
EXT-PC-0.5-100K
EXT-E1-0.1-2.0K
EXT-E2-0.1-2.0K
EXT-IGN-infinity
PC - ALL PINS- infinity
E1-SW-infinity
E1-EXT-infinity
E1-PC-1to5K
E1-IGN-infinity
E2-SW-infinity
E2-EXT-infinity
E2-PC- 1to5K
E2-IGN-infinity
IGN-SW-infinity
IGN-EXT-infinity
IGN-PC-infinity
IGN-E1-infinity
IGN-E2-infinity

If all this stuff checks out ok....You will have to start Ohm-ing out wires in the harness itself.
That is the best answer I can give to check for a "no spark" condition