VS 800 overheating

Hi guys. I started this topic to see if anybody experienced my case , maybe he could give me a few hints before I start with flushing the coolant system.
The bike runs great, coolant level is at the top but after 20 minutes of idling or use the water boils ( overflows from the emergency pipe) and just after a minute the fan kicks in. The weird fing is taht the fan works but the water boils, so it's quite confusing ( on this way i could exclude the fan, temperature switch, coolant level ). I wonder if it's the water pump or the thermostat.
Any sugestion would help. Thank you

is there a diafram in the thermostat? if so just a guess but that might need replacing could be the water pump? hopefully someone more in the no might be able to help

Start her up from cold and see if or when you can see any movement in the see through expansion tank.

The symptoms sound like Thermostat is stuck shut.

I was guessing that the thermostat was stuck. The only problem is sourcing one. The vs 800 unfortunately does not have an expansion tank...would make life easier

On cars we used to temporarily take the thermostat out, not sure here though?

Yeah, Take it out and clean and test it before buying a new one.

turbovax wrote:

I was guessing that the thermostat was stuck. The only problem is sourcing one. The vs 800 unfortunately does not have an expansion tank...would make life easier

If it is knackered these have them, check it's for your model first.
http://www.cmsnl.com/suzuki-vs800-1994-glr_model14246/thermostat-water_1767033410/#.VEy_kPmsVt0

Thank you for your time and help, will drain the system and test the thermostat in a few days as soon as I get some free time from work. Will get back to share the work I carried out, hopefully with some pictures.

I agree, thermostat, you should be able to remove it but you will be running at a lower temperature than recommended but ok until you source a replacement

It's possible there could be an airlock in the cooling system, causing the overheating.

very true Jeff

The last 2 posts begs the questions: Had you topped up or needed to add any coolant before this started to happen?

An airlock in a cooling system can occur during the refilling of the system, ie when renewing the coolant.

Yes and that's why I asked him the question that I did.

Not too sure if just topping up a small amount could cause an airlock, maybe it could.

Have you got any further on curing the overheating?

Could try checking the timing this can cause overheating to!!

good thread , I'm about go start her up after installing a new RAD fan and hoping everything works after the flush... I'm mostly worried about the wiring and if I did it rite because I had painted the bike and at the time did not think about the wires at the time "rookie mistake" but I was able to use some stuff to get some of the paint off but not enough to be sure , I know I have the fan wires connected to the correct wires but I'm not sure about the thermo switch wires... fingers crossed.... and any tips would be greatly appreciated. thanks for the help thus far!