1986 VF500F Radiator fan/temp gauge . 3 questions.

Hi there,

I have a 1986 vf500f, which I picked up for a $100 from someone who was sick of trying to get it to run. After a carb rebuild and syncing it’s running like a champ. Such a cool bike, so cool in fact that my girlfriend has laid claim to it. So I would like to sort out all the little things that are still wrong for her.

Questions! I’ve read a lot of the forums, so I have a good idea as to what’s wrong, just hoping to get more details on what my issues might be and how to go about sorting them out.

1. How long after warmup does the radiator fan generally kick in? I can’t honestly say that I’ve heard it go on by itself, but I haven’t really paid to much attention until I noticed the heat radiating from the bike upwards. Now I can’t tell exactly how hot as my temperature gauge does not function! more on that later. I’ve bypassed the radiator switch so I know the fan gets power and works, I just don’t know if the fax switch works.

2. Temperature gauge doesn’t work. I’ve checked the connection to the thermostat housing and it’s connected. Though I’ve grounded the wire momentarily to check if the temp gauge functions at all while the ignition is on, and nothing. It does not move. So this can be caused due to two things. Temp gauge is fried, or temp gauge is not receiving power to complete the circuit when it’s grounded by me or the thermostat sensor. This leads me to question 3!

3. Speedo, tach, and temp gauge lights do not work. I pulled off the fairing and checked power to the bulbs and I get nothing. I can’t seem to find a wiring diagram for the 1986 specifically so I’m wondering if power to the bulbs also powers the temp gauge? If so does anyone have a wiring diagram for a 1986 vf500f they could share? I have a digital copy of the FSM but the wiring diagram is missing from it.

Sorry for all the questions! Any advice or insight would be cool!

Here's a pic of my girlfriend stealing my bike.

 

Figured it out. Checked for power at every connector and found the problem. All is well and working. Gauge lights work, temp gauge works and fan kicks in once the bike gets to about 60% on the temp gauge.


Sent from my iPhone using Tapatalk

 

Riding the bike, not idling is the best way to test fan switch/fan action. Stop-and-go traffic in warm weather stresses the cooling system to it's max, so any defects show up there. Fresh coolant, new rad cap, and being sure the coolant is topped to the filler neck take care of most problems if the fan's OK. Have you drained and flushed coolant ?

But no need for the fan in Canada, right ?

 

Seems to work fine now, bike doesn't get very hot at all, but you're right, it's starting to get cold up here and the riding season is almost up