www.zxrworld.co.uk

hi ive got a problem with my zxr400 h, after a run of only about 10 miles the heat just goes up and up, i stop it and the water expansion tanks overflow pipe starts leaking, today the fan kicked in for the first time and she was idling terribly, it also randomly cuts out at lights literally just stops. When i rev her when shes hot its not like you blimp the throttle and the revs go up and down it lingers around slowly decreasing the revs back to a very choppy idle.

all suggestions welcomed thank you

chris

Your head gasket has gone. As it's an ex-race bike this is not a surprise, if a ZXR has been tracked / raced a lot the HG is living on borrowed time.

When you change it check the head isn't warped too, which also happens when they've been abused. In which case you'll need it skimmed.

tirpitz is right, deffo HG gone.

could it not be just that the reservoir was very low? i put 500ml in it before the ride home and the needle did get up to hot but alot later on in the journey. ill post a pic of the level inside before a splash of water. has to be said when i stopped her she did make and odd noise when it was switched off and wasnt running perfectly.

here is a video of start up http://www.youtube.com/watch?v=_9mtp3aS ... e=youtu.be

here it is after the ride home today after a couple mins cool down http://www.youtube.com/watch?v=ZyTE5LEC ... e=youtu.be

Is the coolant low because the hg has gone? Or is it just overheating because the coolant hasnt been topped up?

Id be topping the radiator and expansion tank up to thier proper levels (there is a marker on the expansion bottle) and see how it goes. IF the level drops through either coming out the overflow or just through riding then yes you may well have a blown headgasket. You can of course get a compression test done and that should confirm it without doubt.

ok thanks ive got a compression tester so will do that over the bank holiday weekend, am i right in thinking it should be over 90psi? im also going to drain the the entire coolant and re fill as it dosent look all that great condition.

Why is it that people seem to be in denial when it is fairly obvious the HG is blown.
Overheating, cutting out, coolant bubbling
An easy test :- start the bike up, take the cap of the rad if you see bubbles, the cooling system is pressurising. Bad times.

Save yourself the hassle of fucking about and get it replaced.

CaNsA wrote:Why is it that people seem to be in denial when it is fairly obvious the HG is blown.
Overheating, cutting out, coolant bubbling
An easy test :- start the bike up, take the cap of the rad if you see bubbles, the cooling system is pressurising. Bad times.

Save yourself the hassle of fucking about and get it replaced.

yep understand what you are saying just want to be 100% sure before i dive feet first into taking the engine apart, can you recoment other then a head gasket of course anything that is worth buying before i start the job so i wont get slowed down by waiting for orders?

also ive looked all over the rad and cant for the life of me see a rad cap im no novice so its puzzling the bolex off me

thanks

Is the rad cap on the H not under the tank just in front of the air box

I'm sure the manual will have it covered

If that picture is the inside of your expansion tank then it's minging mate. It's either full of rusty water or there's loads of oil in there - i.e. HG has gone.

You should not be adding water to the system, it will dilute the coolant, corrode the engine and fur it up and the engine will run hotter. The system should be filled / topped up with a coolant specifically designed for motorcycle engines (be careful with car coolant, some is not suitable for alloy blocks).

Your problem will not be caused by a low reservoir. It is an expansion tank, not really a reservoir. You said coolant was leaking from it which means it was full to overflowing at some point in your journey, so no amount of extra coolant would have done any good. It is low because the pressure in the system caused by the leaking HG is blowing the coolant out of the reservoir, leaving it empty.

The rad cap on the H is in the same place as on every model (it would be helpful here if people providing info could check their facts with the manual before posting, rather than making a wild guess ). It is on the right hand top of the rad as you sit on the bike, under a fairing infill section which you will need to remove.

pizzaboy wrote:Is the rad cap on the H not under the tank just in front of the air box

I'm sure the manual will have it covered

How is it going to be under the tank when the radiator isn't under the tank? The guy wants help here not daft suggestions.

Tirpitz wrote:

pizzaboy wrote:Is the rad cap on the H not under the tank just in front of the air box

I'm sure the manual will have it covered

How is it going to be under the tank when the radiator isn't under the tank? The guy wants help here not daft suggestions.

He's gotten confused with the expansion bottle.

chrism wrote:ok thanks ive got a compression tester so will do that over the bank holiday weekend, am i right in thinking it should be over 90psi? im also going to drain the the entire coolant and re fill as it dosent look all that great condition.

Manual contains the PSI pressure (which you can find on the main site and reccomend you read) which i just happen to have to hand and service limit is 99-156 psi.

That water looks mucky but think thats corrosion in the cooling system rather than oil, oil and water dont mix. So a good flush wouldnt go amiss and i think you can get fluid specially for the job.

Ive not changed the head gasket but i think youll most definately be needing a torque wrench. Rest i think is just regular tools i.e. allen keys socket set etc... when removing the cam caps loosen each bolt bit by bit, and evenly across the head, undo one all the way while the rest are tight and it will crack the caps and thats a new head as they are specifically matched in each engine.

The bike can also run hotter due to a knackered radiator cap, so may well be worth trying a new one if the compression test draws a nil.

well i removed the coolant flushed the system through cleaned and inspected the water pump and freed up the thermostat which was sticky at first, refilled the system with some sexy clean coolant and 2 weeks in the temperature gauge stays below half and runs as smooth as a nut.