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1987 Honda TRX350 Fan Control Unit Question

2K views 1 reply 1 participant last post by  trx350problems 
#1 ·
Hi All,

I picked up a second-hand 1987 TRX350 (says it was built 10/86 on the frame) and while I've been able to get it to start and idle reliably, it's been having this strange symptom, where sometimes I go to shift it into gear from neutral and it dies as if the kill switch was just engaged. THIS IS NOT HAPPENING AS A RESULT OF A MISADJUSTED CLUTCH. Sorry for the bold statement, but I need to get that out of the way as I know people will recommend this solve first. It dies not from engine load, but clearly as a result of an electrical change to the system.

I've seen some other threads where people talk about how this year has the emergency kill switch included in the fan control unit, so I thought I would start there with my testing. I measured the resistance on the oil temp sensor and found it to be OL, so I'm going to replace that, but I figured that if I were to short out the loop that uses the resistance from the sensor to determine the oil temp, then the fan control sensor should turn the engine off as it would think that the oil is too hot for operation. Sure enough, the oil light came on, and the fan kicked on as well, but the engine kept on running regardless of being in gear or in neutral.

Does this mean that my fan control unit is bad? I've read that other people have suggested the kill switch inside the fan control unit can sometimes cause the symptoms of "dying when switched into gear" as I am experiencing.

If someone thinks it's the clutch or the one-way bearing, then I would like to hear an explanation of why the symptom follows no perceivable pattern, and if it just sits for a few hours it suddenly starts working fine again.

Thank you for any help or advice!
 
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#2 ·
A quick addendum to my above post: Based on additional readings, it sounds like the neutral switch and a temperamental CDI are likely at fault here, but I would still be curious if anyone knows whether or not my test above indicates that the fan control relay is bad.

Thanks!
 
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