Of course, no air going in the top would stop the flow of coolant.

Anyway, after work tomorrow (weather dependant) I will take off the cap and remove the nut. I'm guessing this is how the system is drained?

Should I then flush it through a few times before adding new clean coolant?

Thanks for this,

Lee.

Ye, could be worth taking a couple of pipes off and checking everything is running ok.

Sweet,

I'll do that and post back my results.... Unfortunately it wont be until sat morning as I'm a busy until then.

Thanks.

Hi all,

Just a quick update.

Today I took off the rad cap and loosened the nut on the water pump and there was a hiss of air so Variablevalves you were right. Thank you.
I also took the 2 pipes that connect to the water pump and what came out wasn't good, rusty orange coolant with rust sediment.

So I flushed the system, added new coolant with rad flush additive. I took the bike out for around 90 mins and it never missed a beat. I reflushed it again and added new coolant and it's running well with no backfire or loss of power.

However, I did lose power and stall when I had the fuel set to ON, it may have been due to needing to top up the tank, or possibly needing to clean the lines in the tank.

Thanks for the input and I hope my posts will help someone else too.

Next up,
Carbs stripped, cleaned and balanced.
Fork seals,
Full fairing respray. ( prob Audi blue/silver, cos it's free  )

Lee.

so good to hear another problem solved...