I will flush the radiator out next weekend
Agree that this is the first step. Flush not just drain. Connect up garden hose.
Make sure you refill with a 50:50 mix of "
Distilled" water and an "
Ethylene Glycol" based Antifreeze (important) suitable for use in Aluminium radiators.
Please don't use tap water. All tap water contains imputiries which is why it is so important that you use "distilled" water. It isn't that expensive, a couple of bucks for a 5 litre bottle, or buy a good brand of premixed coolant from a reputable auto parts outlet.
Have a look at the brown muck inside your electric kettle to see what I mean. That cr@p gets circulated around and eventually deposits itself onto your entire cooling system. Thermostats don't open properly, thermatic switches don't turn on your fan when they should, engine temperature sensors don't send the corrct signal to the CDI or ECU, and the vertical tubes of your radiator become blocked.
I had my stator changed about 2 months ago I don't think it is this though
It actually could be this or another electrical problem. A flat battery/bad voltage would account for the fluctuating display and engine stopping. Take a pocket digital multimeter with you on your next hot day and if the engine dies measure your battery at the terminal posts.