350x Issues (Saga III)

[patriot1]

So a few years ago, I bought another guy's project and started putting it together the other day.

Engine has 150 psi compression

Bike came with new wiring harness from South Texas Banshee and new 85 OEM kill switch-I installed.

No spark so I tested the coil, plug, trimmed 1/4 inch off plug wire and still no fire.

double checked ground and tested stator-Stator bad-replaced stator (old stator was white-new stator was red-not positive on the years of each)

We have fire! Trike fired up and ran for around a minute before I killed it.

Tried to start it again and no spark...

Tested everything and eventually replaced the CDI-We have spark again!!

Bike fired right up and ran for a few minutes until it ran out of gas.

Tried to restart it-NO SPARK!!

Repeated steps and ended up at CDI again-replaced it with a 3rd CDI and again we have FIRE.

Started it right up and it ran smoothly until I killed it.

Tried to start it again and NO SPARK again.

All test lead to the CDI again.


What have I done wrong and what do I need to change or check??

Thanks guys-pics coming soon.

[ATC King]

Is the engine stop switch grounding out the CDI or is it somehow hooked up to the power wire and grounding that out instead?

I don't know how those CDIs are built and which wire is used to shut it off. AC CDIs are grounded to kill the spark while DC CDIs just have the power cut. I know the 350X has an AC CDI, because there's no battery.


Most CDIs are held with some type of rubber bracket. They are susceptible to vibration and if it's directly affixed to the frame, the vibration will kill it early, but not that early.

I would think the 350X spark plug cap would have a resistor in it as that's normal for many Honda machines. Sometimes they go out and are replaced with just a piece of metal or a cap that doesn't have a resistor. That shouldn't cause the issue either way, but stranger things have happened.

After running it for a bit, have you tried putting one of the old CDIs back on? Could it be a bad connection and each time it's touched it sorts itself out?

What about the switch itself? Is is clean and functioning properly, not hanging? Maybe a wire grounding out on the handlebars.

[patriot1]

Thanks King.

I just went and tried all three CDI's and all three were still dead.

All three fired and ran until I shut it off and then nothing.

All three are OEM

I have one more but don't want to ruin it too as they are quite costly.

Maybe the stator swap is causing the cdi to burn up??? I know the stator is different from 85-86 and the one I put on was different than the one that I replaced-but it runs (one time) with a new CDI.

[350for350]

Off subject, but did you ever get those two wires figured out?

[ATC King]

You should verify all grounds are good and in the factory location. Also, make sure the engine is grounded to the frame, if you had the frame painted or powder coated.

The issue you're having is not common. It's not a typical problem and something outside of normal troubleshooting is happening.

If there's a bad engine/chassis ground it's likely trying to ground through the CDI when you kill it with the switch. That'll burn one up quick.

I'm a bit late to say that but have been giving it some more thought.



Beyond that, how certain are you the stator wiring connector is correct? Are the headlights hooked up and working?

I ask because you may be running the CDI on the lighting coil. Really, I don't know what that would do because that's a very untypical issue, but the ignition coil doesn't supply the power the way lighting coil does, at least not in a constant voltage way. The ignition coil on the stator is singular (or maybe dual).

In any case, a single cylinder engine with an AC CDI has a dedicated pole or two on the stator that powers it. The lighting or charging poles are a separate system. I'm not a 350X expert, so I don't know if the pulse coil is on the stator too or on the right side of the crank, like is somewhat typical. The pulse coil triggers the CDI, it does nothing else.

Besides going over the grounds with respect to location and connectivity, you may want post the source of your stator and/or a diagram or picture of the connector.

[patriot1]

350: the two wires were optional (like you suggested).

King: Possible problems-Engine is not grounded because the top motor mounts are not hooked up as I was just trying to see if the engine would run. idk?

Stator and flywheel don't match? 350x's apparently came with 3 different stators and the stator has to match the flywheel. I changed the stator but not the flywheel.

Lights!! I have not thought about that but the lights blew out soon after first start because the regulator wasn't connected properly.


ALSO:

I tried all three CDIs on a known good bike and none got fire. I hate to think that I ruined three CDI boxes!

[BOB MARLIN]

As far as the 3 different stator/flywheel combos- I know there is 2 for sure. I believe all the ‘85 models are the same. If you have an 86’ model there are 2 different fly wheels . They changed the 86 early in the production to the new fly wheel and are kind of rare , I happen to have an 86 with the 85 wheel.
The later 86 fly wheel fits farther in towards the center of the engine. They are not interchangeable as the taper is different.

[patriot1]

Thanks Bob: I don't know if the engine would start and run 3 times as it did if my stator/flywheel combo was wrong so right now I am leaning toward the engine not being grounded and it's grounding out to the CDI when I hit the kill switch (like King suggested)

And of course, as is the case when you buy another person's project, I can't find the engine mounting bolts and brackets so I'm going to order some from eBay-and I am all out of working CDIs as well so I might order some china ones or maybe 400ex to use until I can get this figured out.

[ps2fixer]

As far as the 3 different stator/flywheel combos- I know there is 2 for sure. I believe all the ‘85 models are the same. If you have an 86’ model there are 2 different fly wheels . They changed the 86 early in the production to the new fly wheel and are kind of rare , I happen to have an 86 with the 85 wheel.
The later 86 fly wheel fits farther in towards the center of the engine. They are not interchangeable as the taper is different.

Both years used the exact same crank shaft part number, taper is not different on the crank/flywheel. Part number is 13321-HA5-300 if you wanted to look it up. I've talked to several people that have converted their machines between the two styles.


Check for a connection between the black/white wire and green (ground) with a bad CDI hooked up. If there's connection, that would be why it doesn't run (CDI being commanded to turn off).

Of my understanding, internally the power in from the stator for the CDI is hooked to the kill pin and simply shorts the wire to ground, I don't think there's any special circuitry involved. The CDI has a dedicated ground pin which is the companion to the power pin and also is related to the output, aka bad ground would effectively make it not get power, and if somehow it got power it should be able to output to the coil.

Lighting coil is too low of a voltage to run a CDI box, exciter coil at idle is something like 76v when tested on my 85 350x using a peak voltage tester, lighting coil at idle might make 15v. At higher rpm the lighting coil would increase, but 15v isn't going to be enough to fire the coil in the first place.

Internally, the basics of the CDI box is the AC wave runs through a diode which converts it to a DC wave and charges a capacitor. When the pulse generator says to fire, there's some timing related circuitry which ultiamtely commands a part to short the capacitor through the ignlition coil to energize it, once current stops flowing, magnetic field collapses and the high voltage spike happens and the spark plug is where it should discharge though.

Do you know 100% the ignition coil is good and correct? If the output of the CDI was dead shorted (0 ohms instead of 0.1-0.2 ohms) then maybe that would damage the capacitor/SCR but kind of doubt it.

Possible you just had bad luck with getting a bunch of CDI's that have issues. The capacitor inside is well past it's expiration date so to say. A good quality capacitor has a shelf life of roughly 20 years. The CDI's are potted (filled with epoxy) so replacing to "rebuild" it isn't so easy to pull off.

There are 2 different stator designs, and they do need to match the flywheel. The stator you pulled out vs the one you put in, did they physically look the same as far as the wires/windings go? The color shouldn't matter, but if one looks like it has 7 windings, but the other has like 13, then clearly it's different. Attached is a photo for identifying which style you have, as mentioned before, just because the machine is an 86 doesn't mean it will or orig came with the 86 style fly wheel. I'm not 100% sure when the change happened but it was somewhere around the 85-86 model year change over.



If the stator/flywheel isn't matching, I'd start with getting that corrected.

For the south texas harness, I don't know if they are good or not, back when I used to make harnesses they were just popping up on ebay so effectively a direct competitor lol. Some of the design I didn't really like, but unless it was wired wrong I don't think it would be a huge deal.

If you have a multi-meter, could do the stator ohm test right at the CDI connector to validate the connection through the harness is good and correct. I can only assume they are OEM color matched like the ones I used to make.

I'm trying to brainstorm a way that would consistently kill a CDI, about the only thing I can think of is overloading it, like putting too high of voltage into it. On the DC CDI side of things, heat is a big killer on them, they run off a battery/12v, so if the key is left on, it's sitting there powering the CDI with no cooling. I think that's the common killer on the TRX300 CDI's.

For the AC based CDI's, it's more common for the main capacitor to fail (not hold enough charge to fire the coil), or the connector solder joints crack/break at the circuit board. Could carefully cut open a bad CDI on the opposite side of the connector and try to get the epoxy out down to the board and see if the solder joints are cracked. If you have a soldering iron and electrical solder, could try to remelt/reflow the joints and see if that helps/fixes that CDI.

One other way I've seen the AC CDI's fail (not tested myself) is the kill wire doesn't function, so the machine just keeps running. I suspect that's a broken solder joint at the circuit board though.

Hopefully you can get some solid direction from this post, good luck with identifying the root cause.

[ATC King]

There was mention of an extra pair of wires. I'm guessing that's one of the aftermarket stators with an additional lighting coil.

I'm not a fan of those. I get why they do it, but it usually means installing an extra voltage regulator to use the additional circuit, extra wiring and switches. Just beef up the output, upgrade the single VR to one that can handle it, and use higher output lights. No need to add more circuitry and a multitude of extra lights. It sounds good, but in practice it's extra cost, work, and clutter. I don't trust the reliability of them either, after having one or two fail.


I tried to find a 350X specific CDI circuit diagram but all I found was the generic ones. Just guessing from the random CDI diagrams I've looked at, the black/white wire is grounded to shut it off. That looks like it's just completing the source coil circuit ahead of the ignition, cutting the power to it. Pretty much the same concept as old tiller engines with metal strap on the sparkplug.

Although the wire harness incorporates a common ground, the engine still needs a good ground to the frame. Each coil on the stator is grounded to the engine and that's what completes the circuit. There's obviously enough continuity in the system for it all to work and run, but it may just be barley if there's not the correct grounds and it's causing something to go awry.

It's too bad you've gone through multiple CDIs already. I'd suggest shutting off the engine by stalling it instead of using the kill switch. If it fired back up after that, then there's clearly and issue in the wiring, it's not all on the CDI.

Old CDIs are still questionable though, but someone would really be having bad luck to go through that many, that quick, simply because they're old electronics. Maybe the quality control of the original units was so good, so precise, they're all failing at the same time now as the components deteriorate evenly between the tens of thousands of units they produced and shipped all over the world. That's a joke, but it can sure feel true enough to be aggravating.

[ps2fixer]

Just to add in on that, the ignition coil (factory) has the same dedicated ground wire running to the coil, CDI, lights, frame ground, and it also grounds through the stator connectors.

The extra connectors I ignored since there's no pics or anything, I figured it's just the extra ground and lighting coil power for the speedometer assuming the aftermarket harness was a direct copy of the OEM one.

Stock stator specs at 200w of output, so it takes a pretty beefy voltage regulator, if there's two lighting coils I'd assume they'd be lower output each (maybe more combined as a total), but maybe that opens up regulators that normally can't handle the 200w. I was looking for a while for a regulator/rectifier combo that could handle that much but never really found much of anything since it's a single phase stator. I don't know anything about aftermarket stators for that engine though, just generic stuff about stators lol.

My orig research was based around converting the system to DC for a small battery and have it 100% work with all LED lights instead of only some. Some of the power supplies don't work well when AC is powering it, the reverse voltage can damage some parts. Now that I know a little more about electronics, I suspect a transformer to decouple the orig AC ground from the ground output could be an option, but that's an area I haven't worked in before, but if I'm thinking right, it could be a way to float the ground with out having to physically modify the stator. Kind of off topic though.

[ATC King]

Is the switchgear OEM?

In case it's not:

I can't point to any one potential issue with an aftermarket switch because there's so many different ways they're wired. There's some aftermarket switches out there that can do some weird things they shouldn't or are just wired a way that doesn't make complete sense. Some have potential extra functions, extra wires, that don't do anything or do everything they're not supposed to. Some have such poorly written instructions or diagrams that they have to be disassembled for inspection.

I've seen them blow fuses and melt wires when hooked up like the package says. I've also been pleasantly surprised by ones that happen to be built in a way that gives more flexibility with the wiring.

[patriot1]

Thanks guys: A lot of useful info-I'm losing sleep over this thing.

Fixer: I tested each of the cdi's in a good machine and still no spark.

The Stator (stator 1) that I replaced looked like the one pictured in the 85 picture although it was in an 86 engine. The one I replaced it with (stator 2) looked like the one in the 86 picture. I am not sure about the flywheel but I am going to check. Both stators came from 86 engines.

King: Two wires were for accessories like a speedo. The switch appears to be OEM but could be aftermarket because it is new. It plugged right in like the original.

I also noticed that at least one of the copper washers on top of the engine was missing...

Current plan of attack:

1) ordered a couple of cheap CDI's and hopefully they will work well enough to get me through this

2) ordered top brackets to make sure the engine is properly grounded.

3) Make sure all copper washers are installed

4) check and make sure the flywheel/stator go together properly.

5) Get some pics for you guys so you can see what I am seeing-it might be something simple that I missed?

[ps2fixer]

Looks like a reasonable list, the cheap CDI's sadly I didn't have much luck with, I tried several with the 85 style stator, those are known for having issues with aftermarket CDI's though. The 86 style ones generally don't have problems at least for having enough voltage/power to power them. When I tried a 400ex CDI on my machine, I had to repin the connector and it idled great, mid rpm sounded spot on, but any higher it acted like a rev limiter. My guess is the stator wasn't putting out enough power to go above a certain rpm, at least based on my memory, been a while ago since I did the testing lol.

Here's a post I got into the tech stuff a little with, might be a good read.

https://www.3wheelerworld.com/showth...ews-on-ATC350X

[patriot1]

I've already read it-twice lol

good stuff!