VF 500 '86 overheating... any ideas?

Hi all,

My VF500 F2F '86 overheats, if I keep my speed to around 45Mph she's no problem. Idling isnt too bad the fan comes on no problem and cools her back down. I don't know the history so there's not much more i know. Oh and I took a look at the thermostat and it doesn't seem to have one... could that be my problem?

Cheers guys

 

If you have opened up the cooling system you may have air in it...you need to fill up with fresh coolant and "burp the system" you might check your water pump as well....

Good luck

 

No thermostat would certainly seem to be a problem. Start at the radiator cap, on the right. Just below it there is a big rubber hose going down to the motor, between the front and rear cylinders. At the end of that tube should be a housing with two smaller tubes coming out the bottom. The thermostat lives inside that housing.

 

How exactly is it overheating?

My VF500 used to operate in the mid to upper 1/4 of the temp gauge on warmer days.

 

no thermostat would mean no restriction on the flow of coolant... therefore the coolant would just circulate and the engine would not be able to reach proper operating temperature. I used to run my old car that way when I lived in Phoenix....

 

Overheating is usually the result of a flow restriction in the cooling system, clogged radiator tubes, thermostat sticking or not completely opening, water pump shot, water passages clogged. Radiator fins clogged up with bugs and debris is another cause. A leaky head gasket can allow combustion gases to enter the water jacket causing the coolant to overheat.

 

Are you talking about the thermostat or the thermoswitch that activates the fan?

A lack of a thermostat would mean the coolant system is constantly moving fluid, a thermostat closes off flow and opens it up as temperatures in the coolant dictate. Like Crusty said.

 

Thanks for your replies guys. I just took the rad cap off and found some brown gunk with what seemed to be glitter mixed in with it? Ok, at this point i'm well out of my league... I dont know much cooling systems.

The thermostat switch for the fan seems fine, that comes on and off when it gets a bit too warm (the upper1/3 of the gauge). it does have a manual switch for the fan too, which is broke atm...

Whilst im riding it takes atleast 7miles to warm up then if i use top gear or try and acel quickly she gets hot, i dont let it get to the red i always stop as soon as it get to the upper 1/4 and let it cool down.

cheers

 

Brown gunk with glitter in it.....sounds like a PO may have put in some stop leak. Oil in the antifreeze will emulsify into a brown gooey looking gunk, could be a little of that too.....just speculation.

 

Have you thought you might just run lean? Is she accelerating freely?

 

that sounds like a cooling system that needs an flushing......brown gunk with glittery stuff in it? stop leak or your bike has been out raving AGAIN....

 

Like the others said, flush the radiator. The stop leak does a decent job of stopping leaks, but overtime can clog your cooling system and cause problems.