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Discussion Starter #1
HI.
I have a 1989 300 2wd which I just bought with no spark (silly me).
The previous owner informed me that he had tried everything but couldn't get a spark. Now me having a tiny little bit of experience with engines and an unexplainable confidence, I bought the bike and set to work.
Someone had stripped most of the cables and rewired them, I have a wiring diagram so checked everything was wired correctly and at first sight it looked ok.

The connectors for the CDI had been replaced, and the colors are different but has been wired as close as they had guessed.
I already put a new CDI in it but I'm thinking I have probably blown it with the wiring being incorrect.
It is almost impossible to make sense of the drawing when the 4 wires are shown as a line when in reality the connecter is a square block.

Would anyone who has this model and year, mind taking a picture of the CDI where the connectors are so I might work out the pinouts from the unit?


Any help will be much appreciated.

Dave.
 

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How about the bad news first: the 89 TRX300 did not share the wiring harness or CDI with any other year or model

Good news: the colors of the wire pin outs is the same 88-97 except for one wire - 88 was a light green/red wire - 89-97 was a gray wire both 2wd & 4wd

So if you get a pic of a connector for any TRX300 88-97, you should be able to get the right wire on the right pin

More bad news: I do not have any 88 to 97 300's sitting around to take a pic of

Suggestion: get a used wiring harness for a 88-93 TRX300 or TRA300FW, The wire colors might be different, but they are functionally the same - there's one for a 93 on EBAY for $24 and free shipping here - Honda Fourtrax TRX300 TRX 300 ATV OEM WIRING HARNESS | eBay - if nothing else, you can cut the connectors off the used harness and splice them onto your harness

Can anyone else on here help Dayveboy?
 

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Discussion Starter #3
Thanks

I have ordered that harness, thanks!
The one on the bike has been stripped.
Do you know if the wiring diagram lay out indicates which pin the cables are connected to?

If I could work it out, I could just wire the ignition system separately to check its all working.

The CDI I bought (aftermarket) was listed for 88-93, any idea where I could get the right one?


sorry for all the questions.

thanks again.
 

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Wiring diagrams do not indicate which pin goes to which wire and I don't have any pics or wiring notes to indicate that - when you get the wiring harness, you might take some pics and publish that info here for others to refer to

The CDI unit is Honda part 30410-HC4-770 and is about $151 from Honda your local Honda dealer or I can get you one for about $120 and give you free shipping (just takes about a week for me to get one from Honda) - other than that you get used or Chinese aftermarket copies, but usually the Chinese parts work fine - electrically, they are pretty simple units - I have used the Chinese units and they work well
 

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Discussion Starter #5
The part number matches the one I have so I'll see how that works.

Just to make sure I am understanding correctly, this harness will work in place of the stripped one I have? Or just use it for parts / reference?

And one more question if you don't mind, is putting the 18 lug stator in place of the original going to cause me any problems?
 

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The wiring harness should be a direct replacement, but there might be slight differences in certain connectors or wire lengths - evaluate it before shredding what you have

I don't understand the question about the stator - the number of poles may not be important, but the pole that sends the AC voltage to the CDI needs to be in a specific location and the stator needs to fit inside the flywheel. Where did you get an 18 pole stator and how many poles does the installed stator have? Are the number of wires the same and are the connectors correct? You might have an incorrect stator already installed since some aliens have already worked on the machine

Try to post some pictures of the stators and their respective connectors
 

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Discussion Starter #7
I will post pics and a full walkthrough of what happened to get it running (eternal optimist)
The loom that is on there has already been shredded!

Once I know the pinouts I will post a key for this model at least.

thanks
 

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Discussion Starter #8
progress.

Ok so new main Loom arrived and fitted nicely, I also got lights for the dash to show reverse, neutral and oil lights as they were missing.
The solenoid was replaced, it didn't work and I was cranking the engine via my own switch.
Fitted the loom and all the power checks out correctly, no neutral or reverse lights, so I wired the neutral switch to earth (-) and got a light which powered the solenoid and the engine cranked.
I have ordered new switches, haven't ordered the oil switch as I'm not sure if it is a year specific part or not.
I get no response from the oil light, I have read that it should light and go off.

My questions now are:

is there a way to test the alarm unit?
There is no oil in the engine right now, could this be stopping a response from the switch?
Can I test the oil switch?
Is the oil switch specific to the year?

any suggestions?

Thanks in advance for any help.
 

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The test for the alarm unit is simple and FYI, the alarm unit has nothing to do with having or not having spark

At the alarm unit, unplug the connectors - with the main switch on you should have battery voltage between the black and green wires, between the brown/red and green wires and pink to green wire - if you don't have voltage on the black wire, you have a bad connection between the switch and the alarm unit (this is a presumption because you said you have a neutral light and the solenoid closes indicating the switch is making the connection between the red (fused) battery wire and the black wire feeding the black wire in the wiring harness) - if you don't have voltage on the pink wire, it's a blown fuse, bad connection or a bad main switch.

If you have voltage on the brown/red wire, that indicates the oil temp light is good - connecting the brown/red to ground should turn the light on - if the light does not light or just glows, check for a bad bulb or bad connection between the bulb and socket or wires and socket

If the light lights when you ground the brown/red wire, plug the connectors into the alarm unit - remove the blue/red wire from the temp sensor and connect it to ground - if the light comes on, the alarm unit is probably good and the sensor may be bad - if the light does not come on, it's either a bad connection or a faulty alarm unit

The sensor can be tested - remove it from the engine, suspend it in a container of oil, heat the oil - the resistance of the sensor should drop as it heats - it is at it's lowest resistance at about 375 degrees

The sensor is used in various models (250 through 500cc models) from 1987 to 2017

Unfortunately, still nothing to do with spark
 

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Discussion Starter #10
Thanks!
That will make checking it easier!

I'm slightly confused, if the oil sensor (which I now understand is a temp sensor) isn't there to cut the power to the spark circuit, what's the point of it even being there?

I have been staring at this drawing too long, I understood there was a link wire between the alarm unit and the CDI which I assumed was a kill. Looking at the drawing again I can't see it.

I will start testing again, I have replaced every part of the electrical system apart from the rectifier/limiter.

Can't thank you enough for your help in understanding the wiring on this, hopefully the solution will be helpful to the forum.
 

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The sensor's only purpose is to provide a resistance which is read by the alarm unit. When the alarm unit senses that the resistance of the sensor is too low, it turns on the temp light in the dash to signal the operator the oil is too hot and needs to stop the motor to prevent damage.

The alarm unit turns on the light in the dash for a few seconds when the key is turned on so you know the light is not burned out.

No connection between the alarm and the ignition.

The only time I have seen the light come on is from extended idling, extended low speed operation and lugging the motor. If the engine is being lugged and the light comes on, simply downshifting to reduce the lugging is usually sufficient to get the light to go off without stopping. Use of correctly rated oil helps also. Use a 10W30 or 10W40 JASO rated oil is good for year round operation in most climes.
 

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Discussion Starter #12
Thanks.

Got a spark!

Looks like the new cdi box was damaged due to the cut and spliced wiring that was in place with the old loom.

I have all the connector colors and will post pictures tonight/ tomorrow.
 

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Useful photos there- thanks Daveyboy. I too am having to double check things and chasing any possible wire swaps by previous owners on my '88 trx.

I have been scanning back and forwards between the Honda '88, '89 and then the later '89 through to '93 wiring diagrams and it seems to me that while some wires change colour and the actual component names even change in detail slightly, all the wires end up going to the same places between the years.

My eyes end up hurting after a while. At one point I drifted off to sleep.... (wood burner blazing away in room). I'm learning heaps though and hopefully when the new bits turn up I can get the damn thing going!

I must say a big thanks from me to 'here 2 help' for your amazing amount of info, help and suggestions you keep typing out to so many people.

Alex
 

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Discussion Starter #15
Progress

yoeddynz glad the pictures helped a little and yes here to help was more help than he needed to be, knows the ins and outs and helped me get my junker running, eternally grateful!
 
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