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Discussion Starter · #1 ·
Hi I'm Craig just picked up a 87 350D and it has issues. Has anyone had the issue of the fan and oil light constantly as soon as the key is turned on it is a cold engine? No wiring has been modified except the kill switch delete. The quad will normally not start, if it does then you can make it 250 feet or so and it dies. Then no power to fuel pump and no spark. I took a cold reading about 80° off the temp sensor and it is a little low I think 7.7 ohms. I ordered a new sensor, and thinking the CDI and or fancontroller my be the issue. Connections are tight with no corrosion. Any thoughts or suggestions? Thanks
 

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Welcome Craig and to your new D model; i love these quads but getting to the point where parts are no longer available from Honda.

Sounds like you have a service manual? If not, download the service manual from the link in my signature block below—folder TRX350 Foreman.

There is a overheat diagnostics tree that tests the fan control unit and a schematic of the FCU—very basic tho not a wire diagram.

at 77F the sensor should read 9.5 to 10 KOhms; try heating a pan of engine oil as described in the manual. At 212F the Sensor should read between 1.05 and 0.95 KOhm.

it’s possible you may need a carb rebuild and a CDI. Clean connectors with cleaner snd lightly lube with permatex dielectric grease. Heat the CDI in an oven (no more than 200F) for about 3 hours. Let cool completely before you reinstall. Sometimes drying the CDI can revive it. Remember this is a 1-year only model CDI—no other CDI will work. Use the OEM parts finder at Rocky Mountain atv and Partzilla to find this part number

fuel system service. start by making sure the fuel tank is clean and the petcock suctioning lines are clear—use about a foot if weed Wacker line to gently push thru. Look for cracking in fuel lines and change the fuel filter.
 

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Discussion Starter · #3 ·
Goober, thanks I already do have a service manual. Carb has been rebuilt, tank clean. I ordered a sensor just to see if it helps. I read somewhere about the fan switch interrupts power to the CDI and/or fuel pump. Is this true with my 87 model? I did put the CDI in a oven at 200° for about 3 1/2 hours that's when I got it to fire and run about 250' before it shutdown.
 

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On page 22-3 of the manual the FCU (After 87) is indicated to cut power If motor seizes. Don’t know how it does that.

try the oil cooling system diagnostics on page 20-2. Only way i know how to isolate a bad FCU

does your battery pass a load test? I use a Chicago Electric 100A battery tester. Check resistance of your pulse generator. I am inclined to think your CDI is failing.
 

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Discussion Starter · #7 ·
Goober, replaced the fan controller. That fixed the fan from constantly running and oil light staying on. Put a new Honda CDI in, it runs now. Thank you,
 
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