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Ok folks.

Still having issues here.

I initially had concerns because after a hard blast, the ZXR would seem to have boiling coolant, without too much heat.
When I stopped after a long run, I'd hear boiling noises coming from the expansion tank. After some consultation it was suggested that it was probably exhaust fumes being blown into the cooling jackets.

HG has been replaced - original looked to have been blowing, but replacing it hasn't solved the overheating issues.

After 15 miles, I'm still getting the boiling noise from the coolant.

This evening I took out and tested the thermostat, which opened a minute or two before the water in the pan reached boiling, so that seems to be OK to me.

I'm thinking the only other things that could cause this issue are water pump not functioning - which would mean either a severe leak or a sheared spline - I can't see a coolant leak, and the oil is still being pumped, otherwise I'm sure I'd have had a lot more drastic issues by now.

Anyone, any ideas?

Or a blocked coolant system somewhere perhaps?

Check all the breather pipes to make sure they are not blocked or caught between fairings and that as thats what kinda happened to mine, boiled up no water left in the expansion tank and I managed to trap one of the hoses in the fairing

Ciaran

Wifes ER5 had a pinhole in the radiator................................soon enough it over heated..............but the actual leak was not visisble unless you looked really closely.

Perhaps if she'd cleaned it a bit more often I'd have seen it

have you compression tested the new gasket? It could well be you did it wrong or its faulty.

Get the water pump out and see. as for the stat, you need to measure the temperature to be sure its working ok. Is the engine running lean?

I haven't got a compression tester.... Or a thermometer.



I neeeeeeed to get some more speciality tools.

Ok, just bought a nice Sealey compression tester.

What values should I be getting if compression is fine?

All I can get so far is the following;

1 - 180 PSi !
2 - 151 PSi
3 - 156 PSi
4 - 161 PSi

Gonna re-test them.

Thinking about it, should the High-compression pistons mean the compression I'm looking for ought to be higher?


Retest -

1 - 180 PSi
2 - 179 PSi
3 - 185 PSi
4 - 185 PSi

Reasonably consistent then, but that's really quite high, is that right?

according to the bible....

99-156psi @ 330 rpm across all four cylinders.

so apart from cylinder 1 thats pretty much spot on. Dont know wtf is going on with 180 psi tho

are the valve clearances correct?

compression seems spot on, 180 is a little high but a retest proved it to be an anomaly.

You have a base gasket aswell dont you?

Yes, I didn't dick about with the base gasket in the end.

I'm not so surprised at the higher compression - after all, the bike does have high compression pistons, so I should've expected something.

Ok, slight update here.

Discovered today, my fresh, brand new oil, is the colour of horseradish sauce, and far, far too runny - which is only good in that it gives me an explanation as to where the coolant is going.

I can see two possibilities, please feel free to suggest anything else.

1) When Ian and I did the HG, we did it incorrectly. I'm dubious of this as we did it by the book, carefully, and checked everything no less than three times (well, with the exception of the Cam Cap Dowel, which we apparently each thought the other had put back.

2) Cracked liner?

Not a very happy discovery, I'm getting really fed up of this.

You could have a leaky head-gasket.

Even doing things by the book you can have problems, which is why it's imprretive to check coolant levels a lot for the first few rides after changing the HG.

could have a bit of crap in there thats causing a leak. or a craked block somewhere.

Were you having these problems before you changed the HG?

And christ my comp is 103psi on all cylinders.. thats a lot of compression

perhaps the head is deformed slightly, or perhaps there are crack in the bore which are hard to see when the engine is cold and the metal has shrunk

rabidnz wrote:perhaps the head is deformed slightly, or perhaps there are crack in the bore which are hard to see when the engine is cold and the metal has shrunk

then it would be easier to see!