arite could any1 help ive got an overheating problem on my nc 30 when im just pottering round at 30mph it gets really really hot, ive flushed the rad and got a 50/50 mix of water and coolant ive had the fan wired up permently and put it on a switch so i can turn it on when it starts getting hot, im 100% shore theres no air blocks in it. is it possible that the thermostat has gone and if so how do you check its gone, if someone could help it would be much appreciated thanx

Does it overflow into the coolant bottle?

If not, then your rad cap is fucked and the system is not pressurised as it should be.

Check that out asap...

yeah over flows into the bottle then goes back in when it cools down

So, this is only overheating at 30 mph /town riding?

Seems like you will have to get your lower rad off and clean it until you can see though every section of it.

Thermostat stays closed when cold and opens at temp - you could remove it and test it out..but warm the bike first.

I think NC's in general do not like slow speed. Mine has a recored lower rad (no fan) and hates slow speed..but once rolling it is bob on

i left the bottom rad in warm water for 2 days then washed it down with a hose i was carefull not to damage the fins to ill try the thermostat wat do you have to do to test that it works and wat should it do

Have you got a Haynes manual?
It has an great thermostat test in it.

Can you see through the fins on your lower rad?

how fast does the bike heat up? If the thermostat was seized shut it would kill the bike, I am sure.

Seems like a fundemental efficency problem and the fact that you are riding in warmer weather at slow speed....so, normal enough!!

Take the thermostat out, fill a cup with boiling water and lover the stat in, look for the stat opening, simples.

Or you can place it in a pan with water and increase the heat.

its not bad the bottom rad ill try putting it in water c wat it does thanx every1

tried the thermostat to day and its not that ive been told it mite be the waterpump and its developed another missfire when it gets warm now

Mine did this, turned out to be buggered rad cap. Now sorted