Radiator fan

[Dragonslayer]

The bike starts getting warm and overheating when in traffic or sitting still idleing. When I'm moving the temp quickly goes back to normal temp but will start getting hot again while sitting at a light. I don't think the Radiator fan is coming on what should I check for?

Edited September 19, 2008 by Dragonslayer
correction

[Venturous Randy]

Are you going into the red zone? Many of these bikes do not turn on the fan until it is right at it, especially the earlier ones. You may need to check the connection on the switch. Take off the right side grill near the horns and you should be able to see the switch where the hose connects. These wire connections may need to be squeezed a little to fit tighter.

How far is your gauge needle going up?

RandyA

[Dragonslayer]

Are you going into the red zone? Many of these bikes do not turn on the fan until it is right at it, especially the earlier ones. You may need to check the connection on the switch. Take off the right side grill near the horns and you should be able to see the switch where the hose connects. These wire connections may need to be squeezed a little to fit tighter.

How far is your gauge needle going up?

RandyA

Not quite to the red but on a couple of occassions steam started discharging on the ground from the coolant bottle over flow tube.

[bongobobny]

Hmmmm, that doesn't sound good. Maybe time to flush your system? How's your coolant level? You may be low. You probably wouldn't notice a temp difference while moving, but at a stop you would.

 

There is a kit I have seen on ebay a few times that replaces your temp sensor with a lower temp unit and kicks the fan on. Also, if you find your fan is defective, I have a spare or two...

[CrazyHorse]

Is your drain switch on the wrong setting?

 

I put in one of those temp switches that make your fan come on earlier. My temp never reads more than 1/2 now mostly 1/3.

[eagleeye]

This is what happened to my 86VR. The fan mount had moved / bent forward slightly and caused the fan to bind and not turn.

I put one washer under the mounting tabs on each side and that took care of it. I checked it in my driveway by letting it get hot and watching the fan turn on.

Good luck,

Steve

[talonsx2]

Hmmmm, that doesn't sound good. Maybe time to flush your system? How's your coolant level? You may be low. You probably wouldn't notice a temp difference while moving, but at a stop you would.

 

There is a kit I have seen on ebay a few times that replaces your temp sensor with a lower temp unit and kicks the fan on. Also, if you find your fan is defective, I have a spare or two...

 

 

So what is the name of this kit for the fan? my 84 runs hot when sitting at lights as well and I even took the thermostat out...

 

Stay safe and keep the rubber on the road.

 

Michael:banana:

[Condor]

This is what happened to my 86VR. The fan mount had moved / bent forward slightly and caused the fan to bind and not turn.

I put one washer under the mounting tabs on each side and that took care of it. I checked it in my driveway by letting it get hot and watching the fan turn on.

Good luck,

Steve

 

Like Steve says, put it on the center stand and let it idle. The fan should kick on just before the temp needle gets into the red zone. If it doesn't start trouble shooting. You might also think about replacing your radiator cap. It may not be holding pressure and allowing the coolant to boil. Hence the over flow problem.

[bongobobny]

So what is the name of this kit for the fan? my 84 runs hot when sitting at lights as well and I even took the thermostat out...

 

Stay safe and keep the rubber on the road.

 

Michael:banana:

 

Next time I see it on ebay I will PM you the link. Also, keep in mind that the Mk1's temp gauge reads high to begin with. Mine is normally 1/2 to 2/3 depending on how hot a day..

[Venturous Randy]

my 84 runs hot when sitting at lights as well and I even took the thermostat out...

 

 

Michael:banana:

 

If you are running without your thermostat, you may increase cooling problems. Under load, the water can move thru the radiator so fast that it does not cool the water. Turning the by-pass valve does the same thing.

Your 84 probably will not kick the fan on until it is at the edge of the red zone, if you gauge reads typically.

RandyA

[Neil86]

The idling test is good, but verify the fan can run first. Give a fan blade a flick to ensure they can freely rotate, aren't seized or jammed against housing.

On an 87, the thermoswitch is under the right side grille of the radiator...look for a switch facing down with 2 brown wires on the connector. Unplug connector, key on jumper between the 2 brown wires, fan should start...if it does, reconnect and proceed to idling test.

If it didn't start jumpered, test for 12 V on each brown, one should be "hot" with the key on. If neither is, check the FAN fuse...its in the auxiliary fuse panel forward and to the right of the main fuse box...says FUSE on the housing. Its a 10 amp spade, replace and retest at the thermoswitch. If one wire is hot and fan doesn't start jumpered test the motor itself and the ground from the motor. Once operational, proceed to idling test.

Edited September 19, 2008 by Neil86

[Dragonslayer]

The idling test is good, but verify the fan can run first. Give a fan blade a flick to ensure they can freely rotate, aren't seized or jammed against housing.

On an 87, the thermoswitch is under the right side grille of the radiator...look for a switch facing down with 2 brown wires on the connector. Unplug connector, key on jumper between the 2 brown wires, fan should start...if it does, reconnect and proceed to idling test.

If it didn't start jumpered, test for 12 V on each brown, one should be "hot" with the key on. If neither is, check the FAN fuse...its in the auxiliary fuse panel forward and to the right of the main fuse box...says FUSE on the housing. Its a 10 amp spade, replace and retest at the thermoswitch. If one wire is hot and fan doesn't start jumpered test the motor itself and the ground from the motor. Once operational, proceed to idling test.

Good test, good info I will do and post findings

[Gearhead]

One more thing: when you're riding you can tell if the fan is on by feeling for the hot air. When it is running, there is a strong flow of hot air from the little chrom-ish grilles on the radiator side covers. Reach down there with one hand.

 

Jeremy

[venturescott]

Bob, my '86 was doing the same thing a couple of months ago. The problem was a bad connection on the radiator at the switch. My mechanic just cleaned the connection and put back together. No problem since.

The guy with the '84 heating up. Flush your cooling system and put new coolant in PRE-mixed at 50-50. Too much water or too much coolant will cause it to over heat. Make sure its mixed before refilling. Hope this helps.

[bobcat]

I have heard that some will run a seperate switch to the fan so they can turn it on when they feel its necessary...Although I haven't done it myself it seems like a good idea for those that live in hot climates or ride in city traffic a lot....

[Dragonslayer]

Thanks ya'll for your help. I found the problem a blown 10A fan fuse and I KNOW WHY IT BLEW.

Whenever your working on your bike and you drop a screw or a bolt or a washer. Then you look and look and can not find it. When you finally give up convinced the screw fell into a black hole and disappered forever. Well one of those black holes is located in the fan shroud. Evidently I had dropped a bolt that got caught up in the fan shroud and happened to get wedged in a possition where it locked the fan blade.When the fan wanted to run like it was supposed to, and couldn't it popped a fuse just like it was suppossed to to keep from burning the fan motor out.

Go Figure

[Gearhead]

Ahhh...congrats!

 

I have heard that some will run a seperate switch to the fan so they can turn it on when they feel its necessary...

 

Thinking about this myself. I'd rather have one of those temp switches with a lower set point, but don't really want to spend 50 bucks on it.

 

Jeremy

[Dragonslayer]

Ahhh...congrats!

 

 

 

Thinking about this myself. I'd rather have one of those temp switches with a lower set point, but don't really want to spend 50 bucks on it.

 

Jeremy

Hmmmmmmmmmmmmmm Good idea I hadn't thought of that. it would be easy to do.