Changing coolant

Well about the only thing left to do on the ER is to dump and replace the coolant. Simple enough, eh? Just wait 'til I add some uneccessary complexity to the task!

As I see it, I can simply drain the old coolant, flush the system with fresh water, and add new coolant.

Or...

I can use a radiator flushing cleaning product to clean the system out, and then rinse with fresh water and then add the new coolant.

What do you guys do?

In terms of complexity, they don't seem very different.

You're kidding right?

Crikey! I have to open a whole new bottle the second way...

AND ride it around for half an hour....

Just for the sake of argument, Id only do the cleaning solvent if the old coolant colour is looking bad.

sounds fair. As i've only ever had second hand bikes (with past owners that cbf with using a propper pure water/glycol mix) i've always had muddy coloured water in newly purchased bikes. one of the first things i do is flush them out, including taking radiator hoses off and sticking the hose nozzle into the engine, radiator & anywhere else i can for a good blast of high pressure water.

Followed by a good (70-130km) run with an alkaline based radiator cleaner at the propper 10:1 ratio with normal water (i figure it'll be in there such a short time, and i'll be reflushing it again after anyway) and then refill with a 5-10% glycol mix (yes i use pre-mix, it saves on the arsepain of having to find distilled water). Thereafter i do see the radiator running a couple of degrees cooler immediately afterwards. That being said i've never had a totally clogged radiator (thankfully).

Yup I'm with Ment- those cleaners are more likely to do damage than good IMHO in a motorbike engine. I think the cast iron block engines in cars suffer far worse than alloy engined bikes in radiator sludge.
A couple of things to make sure of though- you MUST get all the air out of the cooling system- there may be a couple of bleeders- one on the waterpump and one on the thermostat housing? Also I would run it until all the bubbles disappear from the coolant- you need to have the radiator cap off to do that. Just make sure that the bike coolant doesn't reach 100 degrees ish (coolant boiling point is higher than water alone) coz without the radiator cap fitted the coolant may start to boil. You can run it until the thermostat is open- you will feel the warmth on the thermostat hose when the thermostat opens. Good idea to remove the overflow bottle from the bike and clean that out too. You might need a bottle brush to do it. (not the plant......)
Had cooling problems with my Spada recently- ran fine but after a highway trip up the range it would boil. Had THREE things wrong with it.....took some finding:
Radiator cap wasn't sealing, coolant was in fact plain water, and the thermoswitch for the fan wasn't working.
Bad design though- thermofan comes on at 100 degrees, funnily enough the boiling point of water when your radiator cap isn't sealing. My CB400 has the same thermoswitch in it......bad design I reckon.

So the clean is probably not necessary? Coolant in the bike at the moment actually looks ok. I can get access to water from a water tank, so I can use concentrates or pre-mixed.

What does everyone recommend? I was thinking of using the Nulon stuff.

the stuff i use for cleaning is called tectaloy & is their alkaline stuff as said before. they said it was designed for alloy engines and if a minor clean is needed, only use it for 10km or so, they said for heavier sludge, etc. to use it up until a couple of hours running. Honestly i'd only use it the once on an unknown engine to scrub it out, and then just give a good radiator & block flush thereafter.

It's the acid based ones that i imagine can cause more damage to alloy. I guess the trick is just keep the damned thing in good condition so none of this shit gets in the engine in the first place .

I've used WaterWetter before(not in Australia), and I like it.
http://www.redlineoil.com.au/product-in ... aterwetter

I'm gonna use them on the ZZR250 as soon as I get it back, my radiator is due for a flush.