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fatcat

No spark 88 trx300fw

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Hi there, I left off the other day and had a couple asking how many wires I had coming from my ignition switch. Here’s a pic. Hoping it’s an 88. This pic came from eBay but it’s the same style I have on mine. Still a lot of trouble shooting with the oil alarm and other items. We’ll have her going soon! Thanks 

37C69324-82B3-488F-9CF8-99A81B3EEF18.jpeg

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If you can catch me up with what has been tested or swapped so far I might be able to help out as well.

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Tested the stator and pulse coil. They both check out fine now. I have a new OEM CDI. Bought a used reg/rec. I don’t think I have the right tool to test it though. The oil alarm is concerning me. I have a steady light. Should go off after a while. Going to look into that tonight when I get home. I have a neutral light and the reverse light works when put in reverse. Wiring looks good with the exception of the green ground by the coil. Someone cut it at one time. I soldered it back together and sealed it up. Need to look closer at the wiring diagram as well due to finding a dead ended pink wire back in the battery box. 

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Stator and pulse were replaced (used) with a 12 pole. Kept the original mitsuba flywheel. It had a 12 pole in it but someone hacked all those wires up as well. I’ll try to get some more pictures up tonight. 

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ignition switch wires look correct. if the oil light comes on, and stays on ?, it will not fire the spark plug. this can either be a bad oil temp sensor ?, or a bad alarm unit ?.

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On these older machine the left handle bar kill switch can give problems. A lot of times they are froze in place from not being used. By the left foot peg is the neutral reverse and oil temp sensor wiring. I've seen them get damaged and ground out before which would cause the light to stay on constantly.

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16 minutes ago, toodeep said:

On these older machine the left handle bar kill switch can give problems. A lot of times they are froze in place from not being used. By the left foot peg is the neutral reverse and oil temp sensor wiring. I've seen them get damaged and ground out before which would cause the light to stay on constantly.

neutral, reverse, oil temp switches are on RIGHT side bro :-).

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Just now, toodeep said:

Your correct, I have no clue why I said left.

all good, even I make mistakes !..lol.

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Shadetree, you have nailed it. Everything I’m checking by the book is telling me the oil sensor is shot. Hope to have one by Wednesday and I’ll send a pic of me riding this thing before tear down!!! Thanks 

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He should still have fire even with that sensor bad. These machines didn't have a high temp shut down system. I'm guessing 2 problems that are unrelated.

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2 minutes ago, toodeep said:

He should still have fire even with that sensor bad. These machines didn't have a high temp shut down system. I'm guessing 2 problems that are unrelated.

very well could be ?. I know the old school trx350's were this way, I am not sure ( bad memory ) if the alarm unit stops fire to spark plug on the trx300's or not ?. i've slept sense then..lol.

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Either way, if the temp sensor wire is unplugged the light should go away if the sensor is grounding all the time. If it doesn't it's getting a ground signal somewhere else in the system. I haven't had to work on a lot of these older machines in a long time (just my own) so I'm a little rusty on them also.

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5 minutes ago, toodeep said:

Either way, if the temp sensor wire is unplugged the light should go away if the sensor is grounding all the time. If it doesn't it's getting a ground signal somewhere else in the system. I haven't had to work on a lot of these older machines in a long time (just my own) so I'm a little rusty on them also.

we'll know in a couple days huh ?..lol.

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@toodeepis right, that bike don't have an ignition shutdown in the alarm unit. Even if it did, when you unplugged a grounded oil temp sensor you'd get spark again.

First thing ya wanna do is measure the resistance across the oil temp sensor. The spec is 9.5k ohms to 10.5 k ohms at room temperature (~68 degrees F). If your sensor measures out of range by 10% or more, its junk.

Next thing is to test the alarm unit assuming the wiring harnesses and connectors are in good condition.

 

But the ignition system operates independently from the oil temp alarm circuit. Diagnose the ignition separately using the service manual to guide ya step by step.

Just in case someone swapped parts on ya.... china ignition parts don't work (they supply AC CDIs, LOL) on that bike.

 

EDIT:

FYI: A China ignition coil will fry your OEM CDI as well, due to low primary windings resistance in all china coils, which overheats the OEM CDI, blows a smoky hole in the bottom of them and the motor stalls. Only foolish & wealthy folks can afford to buy china. 🙂

 

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Fellas, I can’t quit troubleshooting this thing. Even though the oil sensor reads bad and I’m waiting on a replacement I thought about the above comments and started troubleshooting back at the beginnng. Following the manual step 4 has you check voltage and continuity at the CDI. They all check normal and that leads me to faulty CDI. Darn it, back to where I started but I’ve bought the new CDI from Rocky Mountain (OEM). Coil ohms out right on the money (all three tests). Pulse generator reads 333 which is within spec. I don’t quite get the AC sensor test. 

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Edited by fatcat

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So... Forget the CDi for a moment, keep it simple...

 

Have you grounded Neutral sensor and oil temp sensor? Read retros post again 🙂

 

Also, from memory I'm pretty sure the neutral sensor and oil sensor are the same ( I could be wrong), try switching them around.

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Also.... Have you tried putting your CDI or FCU in the oven for 20 mins or so at approx 200 degrees?

 

Sometimes they get damp and need some real heat to dry them out.

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Got the AC sensor test dialed in. All checked good. I removed the oil sensor and still had the solid light. Unhooked the alarm and the light goes out. The neutral switch is separate from the oil sensor. I’ll run a jumper to ground from the sensor lead. When I go in tonight I’ll put the alarm in the oven. Thanks gentlemen!! Pat 

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If the oil sensor wire is unplugged and you still have a light the sensor isn't that problem. Something else is giving a ground signal. I will have to look at a wiring diagram to see if there are any connections between the cdi and alarm unit but there shouldn't be any beside power. Did the numbers on the cdi match the numbers on the old cdi or did you check the part number to make sure the correct one was sent?

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On 11/25/2019 at 1:20 PM, fatcat said:

Hi there, I left off the other day and had a couple asking how many wires I had coming from my ignition switch. Here’s a pic. Hoping it’s an 88. This pic came from eBay but it’s the same style I have on mine.

 

Do you have an OEM Honda ignition switch installed? Or is it a cheap china knockoff? If not OEM unplug it immediately and don''t ever plug it in again. Let us know what ya got on this bike.

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It sounds like you have power & grounds going to the wrong places, thats why I am asking about any china parts that might be installed on your bike?

 

Heres the lowdown to help you understand the consequences of possible china parts on your bike... Fact: Your bike has a DC-CDI ignition system in it.

 

  • China ignition switches installed on early Honda ATVs are ALL made for AC-CDI ignition systems but are sold as being compatible for DC-CDI. They are not.. AC-CDI ignition systems SHORT the ignition primary voltage at the CDI output to the Ign coil, which fries OEM DC-CDIs.

 

  • China CDIs sold for early Hondas are AC-CDI too, but are sold as being DC-CDI units. Again, if you plug one of those into a stock Honda electrical system stuff gets fried.

 

  • China coil resistance is so low (on all china coils sold for all years/models) that the primary windings behave as being dead shorts to OEM CDIs and fries them quickly.

 

  • Fact: There is not a single china part sold anywhere that is plug-in-compatible with any of the early Honda ATV models.

 

We need to be certain that there is not a single non-OEM part on your bike. Diagnosis and repair is easy once those suspicions have been put to rest. Hope this helps ya understand the urgency...

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The oil alarm is the only China part on the machine. The CDI and coil are both OEM. I will check the part number on the CDI. I have a used alarm coming today. 

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