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Hi guys and gals, I was hoping i could get a little help with my machine, Last year I found one of deals to good to pass up , I have a 350 4x4 with hardy any use original tires on it . Problem is it has little fits, It will start perfect but when I shift it in gear it shuts off like you trun off the key, Local shop couln't figure it out. I'm thinking electrical but not sure where to start, any idea's?
 

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Welcome to the forums..
I think the first thing I would do is check all the connectors and grounds. invest in soome dieelectric grease for all te connections. I'm thinking your neutral switch may be on the fritz if Helmut has a wiring diagram of this quad i probably can tell you how to bypass it to check it of you don't know how? there's also a section in the Honda service manuals on OHMing out each component too.
 

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I don't have a repair manual for the '86 Fourtrax 350, but I found a wiring diagram in the owner's manual. I posted this twice. I posted it smaller below, it might be easier to follow that way.



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Here it is again a little smaller.



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if this bike is like my '89 trx 350d foreman, and it has been sitting for some time, first thing i would do is over haul the carb, second thing you need to do is check the fuel pump and the fuel pump relay/cutoff,,these things will and do go out,..unhook the fuel line from the pump to carb..crank the engine over...and with the line in a jar or can < this is to keep gas from setting fire >..lol..just hit the start button in short burst..and watch the fuel from the pump..if it is not pumping..then either your pump..or pump relay/cutoff is bad..if this checks out ok..then i would rebuild your carb..after you do this..you may want to check an adjust your valves..this will cause the motor to not run right, < if valves are out, it wont burn the fuel mixture right >..check your intake carb to head boot for any signs of cracks ..holes..you may be getting an air leak ??..if that checks out ok..then move on to the carb rebuild..my best advice to you is...get a repair manual for this bike..it saved me alotttttt of money < i do all my own work on mine and other early model bikes by the way >..if you have any questions..feal free to ask me..and i'll try to point you in the right direction :).
 

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Yeah, I believe I would try cleaning the carb first, too.
 

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i have a 1986 honda fourtrax 250 and it will not spark i unpluged regulator rectifier and it had some black liquid stuff in it can that make not spark
plz help thanks
 

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I would follow Shadtree's advice; he has guided many of us many times. As far as it dying when you put it in gear...Anyone else thinking Oil temp switch or Neutral safety switch?
 

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i have a 1986 honda fourtrax 250 and it will not spark i unpluged regulator rectifier and it had some black liquid stuff in it can that make not spark
plz help thanks
try tapping on the c.d.i as your cranking it over ?..if you get it to spark while doing this ?..then your c.d.i is bad ?..bad coil ?..fouled spark plug ?..bad pulse generator ( pick up coil ), bad stator ?...the reg/rec won't keep it from sparking....it's only purphase..is to convery ac cuttnet to dc current..and recharge the battery..and regulate the voltage to the elec system..for lights and such...it does not effect the spark at the spark plug. main thing's that control your spark....stator...c.d.i. ...pick up coil, and spark plug coil..if any of these parts are bad ?..you won't get a spark.
 

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I would follow Shadtree's advice; he has guided many of us many times. As far as it dying when you put it in gear...Anyone else thinking Oil temp switch or Neutral safety switch?
i highly doubt the neutral switch will stop it from firing...it will keep you from starting it in gear !..but that's all. the oil temp sensor could stop it from firing..as them old bikes ( trx350's ) have a alarm control box that is wired into the fan control and c.d.i..if the fan control unit see's a problem..such as...the oil temp sensor getting a oil reading thats too hot ?..it will sense this..and turn the fan on...if the fan does not cool it down in time ?..it will send a shut down pulse to the c.d.i..then the c.d.i will kill all power to the motor...too keep it from siezing up. this is how the oil temp sensor play's it's part in the old trx350's.
 

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Same problem

I have the identical year and model FourTrax. It starts fine, but intermittantly it will die as soon at the green neutral light goes out, when shifting into gear. Sometimes it runs fine and then dies after riding several minutes, even on cool days.
If it were fuel related, like a problem with the fuel pump, I would expect it to die in a few seconds. When it dies upon shifting into gear, it dies instantly when the neutral light goes out.
I'll be diving into the problem as soon as I get caught up on a couple other things and let you know what I find. Please let me know if you find out anything before I do.
 

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I have a newly aquired one which was doing the same thing. Clutch adjustment fixed it.
 

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id also adjust the clutch. sounds like its too tight and is engaging upon shifting into gear causing the engine to stall. it should engage when you start to accellerate and be free while at idle.
 

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I know this thread is 6 months old. Not sure if you've solved the problem since, or just given up on it :) I posted this on a similar thread. I figured I would repeat it here in case you are still having issues.

It is the CDI unit. Takes about 15 minutes to replace it. Remove the passenger-side fender liner, unplug the unit and wiggle it up. there will just barely enough room to clear the front fairing. Replace, re-connecting the wires, and re-attach the fender liner.

A few notes:
First, On the 1986 (and probably up), there are only three things that the neutral wire is hooked up to.
1) The neutral light
2) The starter
3) The CDI unit.

Second, if you remove the rear seat and look at the wiring harness, you can plug the neutral light line (light-green/red) into the ground line (green) for the oil temperature sensor. This lets you ground the neutral switch even if you break down on the trail and don't have any tools with you.

Third, the neutral switch grounding override hurts your performance. The CDI unit advances the timing when not in neutral to better handle load, similar to the vacuum advance on a distributor.

Fourth, you can test for the problem by disconnecting the neutral switch at idle (either under the seat or underneath the black panel below the clutch adjustment screw). If it stalls out when you disconnect, it's definitely the CDI and not the clutch bearings or anything else.
 
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