1987 Honda TRX250X Starts Sometimes

Brand new plug, tried 3 different ignition coils (original, new, and one from an 86 trx250a which is the one I'm using now), tried 2 different CDI units (original, and 86 trx250a's. Original is back on machine, all plugs have been sprayed with contact cleaner and put back together with dielectric grease, carbs been cleaned twice, valves have been checked twice. I'll be able to start it once then shut it off and start it again, but I'll try and start it up half hour to an hour later and it won't go, then try the next day and it'll fire right up in a first few kicks. Any insight on what could be it's problem would be great. Thanks in advance.

If the external coil and the CDI module have been tested and ruled out, then the stator would need to be checked next. That is assuming that the problem is electrical and not something else. Are you sure that there is a lack of spark when it won't start or is this just a guess?

Just did the spark test (holding plug up to engine and kicking it) one spark out of 15-20 kicks

I unplugged the killswitch and I get spark

...so you have a bad kill switch.

Yes, wired up a dirt bike killswitch and works fine

Never mind, it won't start again

You'll have to go through the wiring very carefully & check all your connections and ground wires for good, clean contact. After that it will take testing using a meter on the stator coils - even good test results don't always mean the part is good though....sometimes you have to try a known, good working one. 

Just went through all the wiring, everything is good, replaced it all with fresh electrical tape, and tested all the connections and everything was within spec. The ignition coil is supposed to be 0.1-0.2 ohms the meter was switching back and forth between 0.2 and 0.3 ohms. Still no spark.

So it sounds like your external ignition coil is likely ok, now it's time to test the stator coils. They are behind the flywheel on the left side of the motor - you should see the wiring that comes from there, you can test them without taking anything apart except the wires' connector. I don't have the specs in front of me but you usually test for resistance between the wires and to check if there's a short to ground.

Stator tests good, 100-300 it tests 190. Also checked all the wires, everything looks good.

The other test you should do is check the stator coil isn't grounded out - there shouldn't be continuity between it and the engine cases. Other than that I suspect you're looking for a wire or connector that looks good but isn't 100% - you have to keep checking them for high resistance somewhere. Does the system use a key switch at all? Not sure if you've bypassed it if there is one....

It works again, after a lot of messing with wires, switching out the boot. We'll see if it works. I'll try it out again later to make sure it still fires.

Sounds good, hope the issue is over with! Sometimes with electrical you think you have it, then it comes back to bite  you again....if it does crap out again, keep checking for a faulty wire that might be intermittent. I've had some that were broken inside of the insulation - looked ok but still made poor connection. Keep wiggling things to see if there's a change. Good luck & good for you to keep the old beast alive!

Started it, it ran. Stopped it and started it again. Messed with some wires connections while it was running, messed with the CDI plugs and it started dying every time I held pressure to the plugs and wires hooked into the plug. I stopped the wheeler and sprayed some contact cleaner where the wires mount to the plug plugged them back in and now it won't start again. Is the CDI going?

Sounds like it's either the connections at the box or the cdi itself....since you already tried another module I'd suspect the wiring in that connector.

Problem was the CDI, I replaced it with a brand new one and she runs great now. Apparently the other CDI I had wasn't compatible with it.

Hey, that's good news! Electrical failures aren't too common that are the modules' fault. They can be tough to diagnose....good that you stuck with it and can now ride that 30 year old!

No such luck for us out here yet - the forest fire situation in the interior of B.C. has a total ban on off roading this summer & it's driving us nuts!!

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