Overheating after a while.

[greg3852]

So after riding for about 45min the temp suddenly rises and rises until it overheats. I shut it down before that. Happens suddenly and usually after about a half hour of riding.

I did find the fan not running. Will the fan not running be a cause of the fan switch or the. Fan? Most often.

Also would the water pump be something I should look at?

I have a newspaper thermostat and a new radiator cap. New fluid too obviously.

 

[WuzzaCBXRider]

Mine overheated just once and the fan fuse was burnt. My fan comes on if the temp gauge rises above the half way mark but then it cools right down. I have the original cap and thermostat as well. I’ve changed the coolant just once in 12 years and probably should change it again I suppose. BTW, what’s a “newspaper” thermostat?

 

[greg3852]

Hahaha autocorrect. Meant to say new.

 

[michael parris heuberger]

Hahaha autocorrect. Meant to say new.

Hi. I will be using a 2nd fan, elect water pump, gutted thermostat take the center out. I also have a high pressure rad cap. And a old Muzzy metal fan blade. I hope that will keep it cool.

 

[greg3852]

I have the high pressure radiator cap. Not sure why it’s overheating

 

[Kiwi Rider]

You need to check for power supply up to the fan, independently test the fan by hooking up 12v directly to the fan connector plug, test the thermoswitch as well, have a look to be Ste all connections are good and secure to the fan and thermoswitch.

 

[busabobh]

You changed the fluid, are you sure you burped it to get all the air out? My fan never comes on when I’m moving more than about 30 mph.

 

[busabobh]

You changed the fluid, are you sure you burped it to get all the air out? My fan never comes on when I’m moving more than about 30 mph.

 

[greg3852]

I’m 99% sure I got it all but I might have not. Are there any surefire ways that people use?

 

[greg3852]

You need to check for power supply up to the fan, independently test the fan by hooking up 12v directly to the fan connector plug, test the thermoswitch as well, have a look to be Ste all connections are good and secure to the fan and thermoswitch.

I’m guessing the thermoswitch would be tested for ohms? I’ll have to check the manual.

 

[WuzzaCBXRider]

I’m 99% sure I got it all but I might have not. Are there any surefire ways that people use?

I’ve always filled the motor thru the lowest opening first and then the rad, run it until I can see that the stat has opened (coolant level dropping and circulating) and then top off and close the system.

 

[Kiwi Rider]

I’ve always filled the motor thru the lowest opening first and then the rad, run it until I can see that the stat has opened (coolant level dropping and circulating) and then top off and close the system.

Very good way of bleeding air from cooling system ya got there Wuzza, I always wait for the fan to start and stop a few times to be sure all is good and the cooling system is functioning correctly.
When dealing with car cooling systems I have a 'dummy' rad cap with a hole in the center and a foot long clear plastic hose connected to said cap.
Top up the hose 2/3 of the height, and it acts as a 'window' into the cooling system. You can see any air bubbles coming up and when they stop coming, and you can also see how efficient the water pump is when revving the engine (thermostat open) the level will go down and up as the revs increase/decrease.
The head height of the coolant in the hose also helps to draw any trapped air out of the system, works so well it's amazing.
When dealing with a bike's cooling system I will be using one of these

because most bike radiator openings are on an angle, and this has a 45deg angle bend allowing it to sit straight up and down.

Bleeding air from systems is easy when you understand how the system works, and you have the right equipment . . 'nuff said.

 

[Kiwi Rider]

I’m guessing the thermoswitch would be tested for ohms? I’ll have to check the manual.

You can remove it from the radiator and place the tip into a pot of water on the stovetop element, heat it and have a multi meter probe on each pin. When the water reaches temp, around boiling point, the ohms reading will go from infinity to 0.00 ohms.
If it stays at infinity, the switch is fooked.

 

[greg3852]

Thanks guys. Got a couple days of rain coming so I’ll start testing. I’m also thinking of replacing everything and saying screw it. There are so few parts to the cooling system and they are 14 yrs old.

 

[greg3852]

Bypassed the fan switch and boom fan came right on. New one was already on its way so...I'm going to wire in a manual switch in line with the fan switch so I can turn it on when I want, and it'll still work as designed.

 

[WuzzaCBXRider]

Don’t know much about electrics but if you put juice to any circuit bypassing the switch wouldn’t whatever you’re ‘connecting’ turn on whether or not the switch is bad? I mean, you’re bypassing the switch so as long as nothing downwind from the switch is bad the fan would come on. Have you put the juice to the switch directly? The switch is set to operate on a certain thermostat temp before it comes on anyway right? Wrong?

 

[greg3852]

I ruled out the fan being bad by bypassing the switch. During the ride the other day, the fan did not come on at all. Now I know the fan itself is good, the only thing there that could be bad causing the fan not to come on is the thermoswitch. Or am I displaying more of my slow mental capacity?

 

[GIXERHP]

It has a air pocket,,, not allowing the fan come on, burp the system while its hot a couple of times

 

[greg3852]

Gotta try burping it some more. Tried today and it still overheated. I’m going to start from scratch. Draining everything and refilling from the bottom up and getting it working. Pain in the ass.

 

[GIXERHP]

Call me when you can