1987 EX temperature gauge high and fan not working - Ex-500.com - The home of the Kawasaki EX500 / Ninja 500R
 1Likes
  • 1 Post By yorkie
 
LinkBack Thread Tools
post #1 of 12 (permalink) Old 4-13-2019, 4:25 PM Thread Starter
Junior Member
 
Join Date: Nov 2018
Posts: 6
 
1987 EX temperature gauge high and fan not working

Hello folks,
I have a bit of a problem with my 1987 EX right now. When I purchased the bike a few months ago, it was not running, the flywheel had thrown a magnet, the carbs were gunked, and it was in need of many other things. After a winter of tinkering, I finally have it running great and all of those problems are resolved (much thanks to these forums!). My problem now is that the temperature gauge reads way too hot after some light riding. The fan does not work either (PO decided to screw up all of the wiring for it so that is a whole other issue), but I wouldn't think it would make a HUGE difference if the fan isn't running on a short ride without any stopping. The bike runs fine, no loss of coolant, it has a fresh coolant flush, and no smoke or indicators of coolant leaks anywhere. I'm pretty stumped with this one. I would like to just wire the fan to be on a switch, as the wiring harness has been tampered with more than I would like, but I'm not really sure how with the '87 model because it has a different temp sensor than the later models. Would this be an issue with the temperature sensors, lack of functioning fan, or is it truly overheating? I have been only taking it for veerry short rides to avoid issues in case it is overheating.
If there is any other information that you need, just ask!

Thanks so much for your help.
Cheers!

Johnny
johnnygreaser64 is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 4-13-2019, 7:36 PM
Senior Member
 
Join Date: Nov 2017
Location: England UK
Posts: 274
 
question is are you sure the engine is getting hot or just relying on the info from the gauge. personally I would think if the wiring been messed with you cannot be sure of anything. except one thing the wiring for the gauge has nothing to do with the wiring for the fan two different circuits.


a question though if you have spent the winter doing it up. and you knew the wiring was butchered why not just change the harness for a un-molested used one. you had it stripped after all.

Last edited by yorkie; 4-13-2019 at 7:43 PM.
yorkie is offline  
post #3 of 12 (permalink) Old 4-13-2019, 7:43 PM
fog
Senior Member
 
Join Date: Oct 2006
Location: Mt home, AR
Posts: 18,912
 
Check the coolant pump open the rad cap and blip the throttle check to see coolant surge. If non you may have a sheared impeller shaft. A cheap replaceable part

Fog

I hate PMs if you want to contact me, find my email address.Look in the for sale section.
fog is offline  
 
post #4 of 12 (permalink) Old 4-14-2019, 2:29 AM
Senior Member
 
po18guy's Avatar
 
Join Date: Aug 2009
Posts: 2,106
 
Garage
IIRC, '87-'88 had a different temp sensor and fan control from '89 and later. Believe the wiring was also different. I know of at least one guy who simply wired his fan to a toggle switch. Kinda crude, but it worked. If the wiring is hacked, it might be worth the effort to locate an unmolested '87 or '88 wiring loom and just replace the whole mess.

1987 EX500-A1<br />K&N/Dynojet kit<br />Webcam 245 cams<br />Cobra F1 slip-ons<br />3rd airbox snorkel<br />Tapered rollers<br />Prog. Springs<br />Russell braided line<br />Galfer pads<br />Avon Super Venoms
po18guy is offline  
post #5 of 12 (permalink) Old 4-14-2019, 1:41 PM Thread Starter
Junior Member
 
Join Date: Nov 2018
Posts: 6
 
Thanks for the responses here fellas.

Yorkie, that is exactly the question I am trying to answer. I did not change the harness because only the sections of it that deal with the fan and temp gauge have been messed with. From there back, it is fine.

FOG, I did check its function already doing that exact test and the coolant pump does indeed work.

Po18guy, you are correct, it does have different sensors and controls for the year of mine. I would be fine with using a toggle switch for the fan, I am just not sure how to wire it.

The temp gauge will read well above red within a few minutes of idling. Are there any surefire ways of testing if it is overheating? Thanks again for these suggestions so far, I am open to any ideas here!

Best

Johnny
johnnygreaser64 is offline  
post #6 of 12 (permalink) Old 4-14-2019, 4:02 PM
Senior Member
 
Join Date: Nov 2017
Location: England UK
Posts: 274
 
Quote:
Originally Posted by johnnygreaser64 View Post
Thanks for the responses here fellas.

Yorkie, that is exactly the question I am trying to answer. I did not change the harness because only the sections of it that deal with the fan and temp gauge have been messed with. From there back, it is fine.

so the next question would be why was that part messed with at all. probable answer because it did not work. there can be only two things wrong.
1. the bike is getting hot really quickly [which it should not after a few mins] I can ride for hrs and never hear the fan kick in, in which case. the thermostat is stuck shut. the rad is blocked. or it's not circulating around the system properly putting the fan on a switch will not cure it.

or 2. the engine temp is fine but the readings you are getting are wrong. could be a faulty gauge. or sender. or even a short in the wiring.


you need to get hold of and read the wiring diagram for you bike and duplicate that on to the bike see what changes. some things you cannot do on the cheap.
yorkie is offline  
post #7 of 12 (permalink) Old 4-14-2019, 4:21 PM Thread Starter
Junior Member
 
Join Date: Nov 2018
Posts: 6
 
The PO messed with it because the temp gauge didn't work (he only had the bike running once or twice while he owned it). The fan does work if I hook power directly up to it. When I got the bike, the thermostat was already out and I tested the bike without it (just temporarily) to see if it was stuck and blocking flow to the radiator. The coolant moved through fine. I then reinstalled the thermostat and coolant still moves through and coolant surges occur when I blip the throttle. I will need to focus more on your second point I think. I have the Haynes manual for the wiring already.

Johnny
johnnygreaser64 is offline  
post #8 of 12 (permalink) Old 4-14-2019, 6:37 PM
Senior Member
 
Join Date: Nov 2017
Location: England UK
Posts: 274
 
I don't think the engine is getting hot, more likely it's a electrical issue. the two temp parts are separate and do not depend on one another to work. start with the fan. can you see any wires in the harness where they have been butchered.

there should be 4 or 5 missing wires. a plain yellow one. a plain blue one. two blue and white ones. and a black and yellow one. if they are not present you may have to cut the outer harness cover a little to find them.


the plain blue one goes to the fan switch top left side of the radiator. the switch has two terminals the blue one goes on one side the other side is where one of the blue/white one goes. that's the switch wired up. then go to the fan. the other blue/white wire from the switch goes to one side of the fan the other side is where the black/yellow one goes. that's it wired up it should work then if the engine gets hot. you can test it by shorting the two wires on the switch the fan should run.

the plain yellow one is the wire from the temp gauge to the sender. you may have to rewire these connections with 2.5mm wire and 16amp female spades. if you have not got them on the bike.
johnnygreaser64 likes this.

Last edited by yorkie; 4-14-2019 at 6:42 PM.
yorkie is offline  
post #9 of 12 (permalink) Old 4-18-2019, 12:11 PM Thread Starter
Junior Member
 
Join Date: Nov 2018
Posts: 6
 
Yorkie, thanks for the helpful reply.
So a bit of an update.. The fan is now working on a switch until I can find one of the single wire 1987 temp sensors like mine has. My wiring is a bit different than you described because I have a first year bike. They have only one wire coming out of each of the temp sensors, instead of the two like later models. The colors of the wires are also different, but using what you said and the manual's diagram, I was at least able to trace most of it back. Comparing the resistance of the temp sensors and the ground, I was able to determine the fan sensor is definitely dead. The other one (for the temp gauge circuit) does vary resistance as the engine gets warmer, but from a range of several hundred megaohms to just a few hundred ohms after a minute or so of idling. I am not sure if I can really compare these values to anything, but it seems incorrect. I would like to just replace the whole darn sensor, but the single-wire ones for the 87's are almost non-existent. Do you know if I could wire up one of the later ones to work? I think that would be my best bet.

Thanks

Johnny
johnnygreaser64 is offline  
post #10 of 12 (permalink) Old 4-18-2019, 3:11 PM
Senior Member
 
Join Date: Nov 2017
Location: England UK
Posts: 274
 
of course you can. it just a matter of reworking the wiring to suit. like the fan it has to have two terminal on it one for power one for earth return.
if not a later fan can be fitted. this is half the circuit. the other half the fans switch as far as I know all radiators are the same so the later switch should just screw in. then you have two terminals to work with. power one from a ignition feed. to the switch [there is a spare one on fuse box 2nd one in from the right, I believe [it's actually not got anything plug in there] goes to one side of the switch the other one on the switch just goes to the fan power in the other to a earth point somewhere. that's it completed stand alone circuit that works independently.


the sensor for the gauge has only one wire [yellow one later models] there all the same thread so a later one will screw in connect this up with one end of the wire and trace back to the clockset to find the right sensor wire splice into that and the gauge should work normally.
yorkie is offline  
post #11 of 12 (permalink) Old 4-18-2019, 8:19 PM
Senior Member
 
Saabnut's Avatar
 
Join Date: Feb 2012
Location: Santa Rosa, CA
Posts: 2,254
 
Jumping in here a bit late, though I did read all the posts to get myself up to date.

As mentioned, the 1987 and 1988 models (what I sometimes refer as the silver frames due to the unique silver painted frames) use a different fan switch (again, as noted, a single wire compared to the later 2 wire) and thus different wiring harness and radiator. @yorkie, the early style has the fan switch on the lower right of the radiator compared to the standard upper left. The fan itself is the same between the two versions, as are the temp sensors on the thermostat housing.

As for the differences in the wiring harness, it sounds like the OP has that generally figured out, though I'd like to point out that the early harness has a ground wire connected to the top center of the radiator which the standard harness does not have. It may or may not have to do with the cooling system, check to make sure that is present and connected.

@johnnygreaser64, I've got one spare early style single wire fan switch as well as the matching radiator and wiring harness, all of which I recall working when I tore the bike down, though that was 6 years ago. Tell me what you want and I'll see about digging it up. Can't guarantee how soon I can get it in the mail, my life has been hectic, but I can try my best.

1990 EX500 - 139,000 miles as of April 29th, 2019
1993 Ducati 900SS - The real canyon carver
2002 EX500 - Undergoing a full restoration
Saabnut is offline  
post #12 of 12 (permalink) Old 4-19-2019, 5:01 AM
Senior Member
 
Join Date: Nov 2017
Location: England UK
Posts: 274
 
@Saabnut, thanks for that info I see the difference but you have to remember I have never seen a US spec bike here in Europe the models are different I just assumed they were the same. you referred to the early ones as silver frames. all are gen 1's have silver frames
yorkie is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ex-500.com - The home of the Kawasaki EX500 / Ninja 500R forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome