How hot does your ZXR run?

[RedexRobB]

Headgasket.

If its leaking fluid out of the resevoir then the system is either being pressurised or its just getting exceptionally hot, which it is by the sounds of it. Might wanna get that checked with a compression tester to confirm.

[Gemini]

head gasket?...

[rover220]

right, best thing i can advise is this...

drain the cooling system, stick a hosepipe in the rad and any other pipes you can get at and flush it all through.

refill slowly through the rad filler to about an inch from the top. squezze pipes gently to expel as much air as possible.

this part might take a few attempts so it wont be easy, from cold, run the bike with rad cap off for as long as possible till it overflows. squeeze all pipes or tap them to help air out. turn it off when it overflows. if you still getting air bubbles then do it again. dont let it get too hot though,

where abouts are you?

[rene]

i've always just drained the system completly (including the 2 bolts on the engine behind the rad) then filled the system, start the bike and keep topping the rad up till completly full and the bubels stop coming out of the system. Never had problems with any of my bikes getting airlocks doing it this way.

[Northern ANdy]

the rad is still full when the stat is closed, it doesn't fill from the bottle.

[crushedlizard]

the rad is still full when the stat is closed, it doesn't fill from the bottle.

Haha, that's a very good point - otherwise I'd have a hell lot of trapped air!
How did I miss that? toad, I'm being quite dense recently...

[RedexRobB]

Is it just me or does this scream of blown headgasket?

[Gemini]

i put that last night but for some reason it aint been posted. i think the head gasket has failed too

soz dude

gem

[crushedlizard]

Is it just me or does this scream of blown headgasket?

Don't say that! I must admit, it did seem bit smoky the other day. It's not really bad hence I took no real notice but now you mention the head gasket.

Am I right in thinking white, slightly sweet smelling smoke is coolant ie head gasket?

[RedexRobB]

i put that last night but for some reason it aint been posted. i think the head gasket has failed too

soz dude

gem

Ditto! I looked at the thread and you were last to have posted but your post wasnt there, and neither was mine!

Get a compression test done mate, only way to confirm it. It could be the stat/thermistor or whatever is it being stuck, so check those also. Basically it wouldnt piss out water unless it was pressurised or the coolant is getting exceptionally hot, which i think is the latter as yours is running hotter than normal, so that could be down to the head gasket or maybe the the stat/thermistor getting stuck closed. How many miles has the bike done? If its roughly 20k you could be looking at the gasket unfortunately.

[crushedlizard]

If its roughly 20k you could be looking at the gasket unfortunately.

It's done 18000km and is 15yrs old so I wouldn't be surprised if things are starting to perish.
I just picked it up from having a new rear tyre and there is no smoke, so perhaps that was just a combination of cold morning/choke etc. I'll get a compression tester on it later this afternoon. Any idea what PSI/bar it should read?

Strange thing is, it didn't overheat on my way home just now but when I stopped there was a bubbling sound coming from near the reservoir so is this trapped air? I took the cap off and there was no hiss and coolant level was actually bang in the middle of the low/high marks.

Anyway, I'm gonna head home (I'm at uni at the mo) and so the 40mile thrash should f*** her up again!
I've got all my tools down there so weather permitting, I'll have her apart. I'll let you know how I get on.

Sorry for clogging up the 'Free for All'. What started out as a simple question turned into a full on Q&A!

Thanks again for all the help.

[RedexRobB]

It states exactly in the manual but from memory i think its somewhere around 100psi. The bubbling could be trapped air, i think Gem's ZXR did that but didnt have a blown head gasket and ran fine....

Get a compression test and go from there mate.

[Gemini]

yeah my expansion bottle used to bubble but HG was fine, ran ok and didnt overheat after i put antifreeze in it

gem

[Jamz]

Omm!!!

You've gone and said it now!!!

I was trying to avoid mentioning the 'H' word...

When mine went there was no noticable loss in power, no oil in the coolant or coolant in the oil, and nothing at all showing wrong with it other than it would overheat and piss coolant out of the overflow.

[Northern ANdy]

the expansion bottle wont hiss, its got a breather.