Just got back from riding the bike after sorting the brakes, and when I was out I noticed that if I was stuck at a set of lights idling for a while the engine temp shot right up.

I constantly have the rad fan on (manual switch) and I flushed the rads and changed the coolant before I put the bike on the road after passing my test.

Is this normal, or should I be looking for a slight problem?

When you say shot right up how high did it get and how quickly? I think it could be either an air lock somewhere in the system, or the lower radiator is so clogged up with dirt and crap that the fan is having no effect at all. Its such an annoying problem i avoid riding in town like the plauge when im out on the NC30 but hopefully all will change when i fit my new lower rad.

I had a similar problem, turned out it was the temp sensor on the thermostat

Since you just changed the coolant, I would try to burp the system first. It sounds like you have some air in there.

Why are you running with the fan always on? What ills is that bodge hiding?

The temp goes from about 80 to over 90 pretty quickly, like a minute or so and its up there and the idlings rough.

When I filled the system with new coolant I squeezed all the hoses and revved the engine slightly etc etc, I'm guessing this is what you mean by burping.

The lower rad is pretty crudded to be honest, and the fan switch has been there since I bought the bike. So I'm guessing a previous owner fitted it due to the fan sensor going and it being expensive to replace?

I'll got for a knackered rad cap then - not enough pressure in the system.

Clean the rads too..ballache, but worth it

Yeah the rad cap did seem past it, do you know where I could get a new/replacement one?

And would a compressor clean the rads well enough, I've just discovered we've got my grandads old one in the shed!

I'd get one from geoff - I have a spare I think though, looks rough, but always worked!

Compressor would fuck the rad...the fins are brittle and the would probably snap off...

Soaked in water for a day or so...then under a tap and with an old needle to dislodge the heavy shit. Then mine take a dishwasher trip...and another run under the tap...repeat until complete

I already have a new set from geoff, was buying new parts and stuff to put on all at once after my restriction ends. I'd just want to get some samco's first.

Starting to think about getting the mechanics sorted without waiting anyway, to make the bike working perfect, then look at the aesthetics.
Saying that I bought a new v-panel the other week, mainly for the grill, but its original honda and in silver, matching my type 2 scheme instead of my current black v-piece.

I've already fully serviced the engine (minus new plugs and air filter as they were fine), overhauled the front brakes, sorted the electric leak, replaced throttle cables and battery.

Plus a couple of extras, so as you can imagine funds aren't there for a bit to be able to get the samco's.