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So is the valve failing a result of water in the fluid? or vise versa?

Good question


I'd ve surprised if the first thing to fail after all the coolant was lost was a valve.

so IF something happened to cuase the coolant to go AWOL then likely the broken valve happened after somethng else failed

However looking at those pictures and the coolant that has got out through the carbs into the airbox I'd say something happened to the valve. U-Horn noticed a drop in power.............that was the valve letting go as he rode on the coolant seems to have got out via damage done by the valve and riding on has mixed it nicely with the oil hence the milky appearance. Thats my best guess from here without seeing it for myself


I'd be curious to know if any work has been done recently like valve clearances or new cam chain............in case that has been the cause ?

having said that ZXR400s are getting very old now and high reving is bound to take it's toll eventually so a valve going for a stroll in the head is no surprise.

I always like to see a nicely destroyed engine something satisfiying about it


Also nice to have a spare one to just throw in

Ok well I have got the engine out and its on the worktop. If I'm going to strip it down do I need to worry about putting it to TDC as it is all going to be coming apart anyway?

Tried to get the spark plugs out 3 of them were fine little oily, the 2nd one snapped when I was trying to get it out! There will be more pictures up today and the weekend to show you the damage that I've done. Never thought that I would be able to blow an engine lol. Always a first for everything.

Yeah, just been collecting things over time for racing and got a couple of engines on the cheap, hopefully it works but not really looking to hopeful about it as it has been sitting idle for a very long time.

I'd not worry too much about TDC................you'll have to pull it right down to get it cleaned out..................

In all honesty I wouldnt spend too much money fixing it might be better to just keep the good bits as spares.


Your spare wont have suffered from sitting unless it's been for years and years....................it should be fine assuming it was all ok when you bought it.


Get it in throw some fresh oil into it. get it started and robert will be your mothers brother

It has been sitting for a like 2-3 years it was another post on here. All that was gone was the head gasket ans changed that for a new one so fingers crossed. Just got to wait for some new exhaust gaskets so its all complete.

I'll end up having to change this one as well lol

Well I was just going to strip it down for a bit of knowledge and just to see what has happened to it, was just thinking about keeping it as spare parts or selling them if they are still alright.

Your not going to believe your eye with these pics!!!!

Spark Plug snapped and in block



Sure there is meant to be a bit of a valve stem here!


One mashed cylinder






Thats what it looks like lol. Would anyone know what might have actually caused this to happen? There is a bit of a crack in the cylinder casing (I think you can see in the picture)

fooking hell that IS impressive
I will wait until I get home to see it on a big screen and pronounce my judgement.
That needs hung up on the wall

cargo wrote:That needs hung up on the wall

Wow, ive never seen anything like that before. Surely that hole has been burnt through and then hammered by the valves? That crack will explain why the coolant is on the oil i suppose.

think you have killed your engine!!!

masterofinsanity wrote:think you have killed your engine!!!

A bit of T-Cut should fix that nicely

It's kind of difficult to be certain exactyl what has caused this clearly something went baddly wrong but what atarted this chain of events is not clear........

I'm not entirely convinced that the piston has melted or even got overheated.................it might even be that the crack in the liner was the first thing to happen unlikely but possible

My best guess is that something has happened to a valve either it broke or dropped this two little bits of valve collet would suggest this............after that bit of valve bouncing around in the cylinder did the rest.............the spark plug probably broke because it was so badly damaged that it could not screw out and so broke at the weakest point..................

It is a wonderful example of a engine failure and I'd have all of it hanging on the wall as a warning/reminder of what can happen when it all goes pete tong

news on the replacment engine would be most welcome

Seeing a few examples like these just make me want to have a good spare engine..i might just get a spare 1 or old 1 as spare

would just like to add here, failures like that are quite rare on the ZXR.

Yeah I know, its quite interesting my other bike has done 49,000 hard miles which does not include all my track days and racing and nothing wrong with that one!

Rob makes a very valid point when I first got my ZXR lots of people warned me about valve problems and how they broke or bent and wrecked engines.
One guy even insisted that I bought a set of stainless REC one piece valves.................

In over ten years of ZXRing.............I've bent one valve and I know how and why and I realised something was not quite right and was able to remove it with no other damage.
The only other engine failure I've had was caused by a serious lack of oil most of it was on my back tyre.............

I have a theroy that the valve problems are a result of poorly built engines.......they are a fiddly bugger to rebuild especially for big fat sasuage fingered knobs like me.

Generally ZXRs are very reliable almost indestructable................but not quite