Honda ATV Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Been playing outside in the snow lots lately and now after about a hour of use, it will just die. Fires back up no probem. It as soon as it’s clicked in to gear it dies. The fan doesn’t always run but sometimes it does while this happens. I can be ripping around , stop and put it in neutral , talk for maybe a minute or 2, shift in to gear and it dies. I think it’s a over heating issue? My oil pump? Read maybe it’s a carb not working properly ? Planning to park till spring then work on it in my shed. I’m in Canada and right now it’s pretty cold (-8 c ) so the over heating just confuses me a bit more if it’s that. Would appreciate input. Thanks to those who read and respond !!
 

·
Premium Member
Joined
·
2,608 Posts
Tap the CDI module while this problem is occurring. If it starts up, you have either a cold solder joint or a broken trace on the CDI (Capacitive Discharge Ignition) printed circuit board. This part is number 3 at the link below:

https://www.cheapcycleparts.com/oemparts/a/hon/506babd8f870023420a21358/wire-harness

Yes, it is a little expensive but at least the part is still available as an OEM Honda part. Very few people here would recommend a less expensive aftermarket part because we have all seen them fail quickly. Your CDI is probably repairable but it was never intended to be repaired as Honda made getting to the printed circuit board extremely difficult - sealed up tightly. Yet, others have done it with careful Dremel tool cutting and then handy use of a soldering iron.

Rick
 

·
Registered
Joined
·
677 Posts
It could be a CDI, but chances are slim. Take the carb off, and clean it. Carb cleaner and compressed air will work. May as well change the spark plug at the same time.
 

·
Registered
Joined
·
677 Posts
You are disengaging the choke after the engine warms up, Rite???
 

·
Registered
Joined
·
5 Posts
Discussion Starter #6
Yes, I turn choke off immediately once it’s warm. If it’s not warm while warming up and it goes in gear it will act very much the same as when it stalls while I’m riding . It just dies. I will try tapping my cod module while this is happening. If I let it sit for 10 minutes it will usually go for long enough for me to get home( from the neighbors) but it can die/ stall out during that too.
I’m looking at diagrams , the cdi is located under my head light, sort of? Under my front plastic?

Very thankful for all the input in under 12 hours of posting initial thread. Thanks everyone.
 

·
Premium Member
Joined
·
4,702 Posts
Check link in my sig block for service manual as TRX350 Foreman (86-89)
CDI for 86 is not interchangeable with other models; should be accessible from under an inner fender
 

·
Registered
Joined
·
677 Posts
B52 & Goober, Are you guys finding with the cold solder joint issue that even after a dozen or so fails the CDI is still coming back to life??
 

·
Premium Member
Joined
·
2,608 Posts
Yes, this is a common problem where the gaps in the cracks in the printed circuit boards or the solder joints change in continuity with temperature or vibration. And it was years of temperature change and vibration that likely caused the problem in the first place. Tapping sometimes can temporarily bring it back to life. An actual failure of a component part (transistor, capacitor, resistor, etc) on the board is apparently rare.

Lots of stuff on the Internet about this. The absolute toughest part is getting through the epoxy potting compound inside the CDI case to get down to the board for the re-heat and reflow of the solder. And then there is no guarantee it won't happen again.

Rick
 
  • Like
Reactions: retro

·
Registered
Joined
·
5 Posts
Discussion Starter #10
Last post before I take action, trying to determine if it could be my carb .I have zero idle issues, never sputters out and when it does die, it’s like I hit the kill switch, there’s no trying to keep the revs going. I’ve been watching YouTube videos of people with similar problem but they bike idles poorly, mine does not and hasn’t ever sounded weird or off beat
 

·
Premium Member
Joined
·
4,702 Posts
If your spark plug is clean, then you may consider that the carb may not be the cause.

I replaced a CDI on mine–it ran good one day and the next it was dead and never restarted. That CDI has a crack in the sealant.

Your problem might also be the fuel pump–look at the shop manual ignition diagnostics. the fuel pump is controlled by a couple of components–which could also fail. Run the diagnostic flowchart and Try isolating the fuel pump. The guys at the shop have a little fuel can with a hose they gravity feed to the carb to diagnose fuel pump concerns.

I replaced the fuel pump on mine because it was leaking.

If you are able to start it by tapping on the CDI replace the CDI. It’s the one component that you can’t troubleshoot
 

·
Registered
Joined
·
160 Posts
Couple of hints.

I have a Briggs and Stratton spark tester # 19368 (about $15 from flea bay) that can readily be connected in series (engine will run while it's connected in series if it has spark) with a spark plug wire to watch for intermittent ignition spark or you can clip one end to ground and check spark while you crank the engine. (it has a clear viewing window) You can see the intensity of the spark and if it's weak it's readily apparent, but to view a really hot white spark the little window may have to be shaded. I use this Briggs type instead of the spark type that has the light bulb because the lamp type will still flash with weak spark.

The other option for you to check for spark (to get an idea if it's CDI ignition failure or ignition spark failure) is too keep a spark plug readily available and connect it too the spark plug wire and get a good ground on the spark plug body.

You indicate that you can let it cool off and get a re-start and when it quits it immediately quits like you used the kill switch. If you find you are losing ignition spark investigate the kill switch also.

Next you indicate that the cooling fan runs sometimes when the engine quits and in cold weather in the snow and the engine might be overheating.
Here is a link to a IR thermometer ($18) with free shipping. You can use one of these to actually get a instant temp reading of you block.
https://www.solidsignal.com/pview.asp?p=irtherm716


I think the oil temp sensor that activates the fan is listed in the service manual. (the temperature at which the oil block sensor activates the fan and the red temp light)
I'm not sure but I seem to think the block temp or oil might be around 180-190F but not sure. (anyway the NON-contact IR sensor will tell you immediately the block temp) I use a IR thermometer for several things when working on engines and heat air. Goober and or Shadetree may know the temp of the oil sensor. See that the oil coolers fins are not clogged with mud/gunk.

Next: If you find out that it's fuel delivery issue, their is a fuel pump control relay up under the right rear fender under a cover that controls the fuel pump. If this relay gets erratic the fuel pump will get erratic, but usually a choke would be required or a longer crank time to re-start the machine. (get gas to a dry carb)

Your description of the beast kinda indicates ignition shutdown. (instant failure)

When the cooling fan runs does the oil temp light come on? (if the RED temp light comes on I would quit running the machine until I checked the block temp due to engine being damaged)

If you don't have a 86 Fourtrax service manual you can download one from this site.

Keep in mind that a bad battery cable connection will shut down a 86 fourtrax ignition because the 12v is feeding the CDI module. (must have 12v bat to run the ignition)

and IMHO you need to be concerned about the cooling fan running in cold weather. (not a good thing)
Section 20 of the service manual has some real good troubleshooting tips for the Fan control.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #13
After it shuts down ( only ever while in gear)
It will always start back up with zero issue.
I can idle it in neutral, rev it up and the oil temp light doesn’t turn on. The fan is hardly on. And even the odd time it is I can idle fine or possibly be riding. The main problem is it runs fine while it’s in neutral then when I put it in gear forward or reverse it dies. I don’t think it would be the kill switch, and unless the gear dictates the fuel pump functions I have doubts there too. Not trying to be defiant, or indisisive . Weather is really ugly now so I don’t have immediate plans to be working on it. It sure if the little bit of rectifying helps further isolate my issue
 

·
Premium Member
Joined
·
5,956 Posts
I just found this thread (and haven't read through it) so this might be irrelevant but... does the bike try to lurch forward or backward when you put it in gear? Or does it just quit running, as if you suddenly turned the key switch off?

If the former, then its likely a clutch adjustment issue. If the latter, then its likely that a primary (ignition) wire is grounding out somewhere OR, either the key switch is going bad or the kill switch is...

The 86 Fourtrax TRX350 has an AC-CDI ignition system. So grounding of the primary voltage is how the motor is normally shut down. You can begin to isolate the issue by unplugging the kill switch and see if it still stalls... then try unplugging the two ignition switch wires, if the kill switch seems ok. Check the harness connectors at the CDI for pushed in pins... and check the stator harness where it comes out through the rubber grommet on the upper-left side cover area for rubbed-through bare wires.

EDIT:
Also check the regulator/rectifier harness for rubbed bare wires where it bends around next to the upper-right rear shock absorber mount and enters the little black tin box under the right-rear fender. The rubber grommet may be out of place or missing where the harness enters that fuel pump relay/connector box.... if so those harness wires will be cut.
 

·
Premium Member
Joined
·
5,956 Posts
I didn't mention the wire colors you'll need to unplug from the kill switch and ignition switch for testing purposes... Unplug only the black/white wire and the green wire from each switch. Test them individually because you'll need one of those switches connected in order to shut the motor off.

Edit:
Well, I screwed that suggestion up... unplug only the black/white wire from those two switches during each test. Tape the plugs up while unplugged so they don't touch anything.
 

·
Registered
Joined
·
160 Posts
After it shuts down ( only ever while in gear)
It will always start back up with zero issue.
I can idle it in neutral, rev it up and the oil temp light doesn’t turn on. The fan is hardly on. And even the odd time it is I can idle fine or possibly be riding. The main problem is it runs fine while it’s in neutral then when I put it in gear forward or reverse it dies. I don’t think it would be the kill switch, and unless the gear dictates the fuel pump functions I have doubts there too. Not trying to be defiant, or indisisive . Weather is really ugly now so I don’t have immediate plans to be working on it. It sure if the little bit of rectifying helps further isolate my issue
Does it ever die or while the ATV is moving down the road at a moderate speed or do you ever hear the engine cut out at a moderate speed? (like it's related to vibration movement)

When you pull up on the shifter from neutral to first gear (for example) does the bike remain calm (not lurch) if you hold the shifter up on the shifter with your toe? The ATV should not move until you start slowly releasing the shifter. Reason I ask this is if the ATV idle is too slow the immediate load will kill the engine or the clutch is out of adjustment placing a load on a engine that is idling real slow?????
 

·
Registered
Joined
·
5 Posts
Discussion Starter #17
It slightly jumps, if I’ve revved the engine slightly, but dies as tho the key was turned or moving the kill switch to one side or the other. In the winter I’m not Realy driving fast or far but just slow trail riding and plow if my 25’ driveway ( not much snow this year), it has once or twice maybe, cruising down a driveway it was died, will always fire back up in neutral and continue to die once engaged back in gear. I can be riding, put it in neutral, talk for a second, go back in to gear and it will die again. ( this is repeated but new reply mentions he hadn’t read entire forum.) Is it normal for it to stall out when put in gear prior to the engine being to running temp? It acts the same if so, and if not then maybe that would help determine further .
 

·
Premium Member
Joined
·
4,702 Posts
I would start by checking the wires on the neutral and reverse switches. Check the schematic to see if the neutral switch or another input is grounded and inhibiting the ignition circuit.
 

·
Premium Member
Joined
·
4,702 Posts
Hey @Tarswell21 how’s it goin probably still too cold for you to take a closer look.
Check page 20-2 on the ignition troubleshooting flowchart. It sounds like something simple but you gotta look at everything that might inhibit ignition. Might as well start with the oil sensor and R N switches
 
1 - 20 of 21 Posts
Top