I've had enough of this - the HEAD GASKET thread

[deviant]

It seems to be received wisdom on here that ZXR400 head gaskets will suddenly go pop as soon as the odometer clicks over to 20,000 miles and any bike with more than 20k on that hasn't had it done is a ticking time bomb (or something like that).

So I thought I'd try a bit of research. Only vote in the poll if you have had a head gasket blow on a ZXR (I haven't, so I'm not voting). If you've had it happen more than once on the same bike, or on different bikes, then vote for the minimum and post a reply with the others in.

[RedexRobB]

Just over 25K mine went on my first ZXR. I dont think anyone has ever said that the head gasket will go bang on 20K, its usually 'around' that mileage i would say they go.

[Caz]

*rolls eyes*

good poll deviant! Im not voting as my ZXR has done about 40,000 miles and the headgasket is still a-ok!

can I add, if your head gasket has gone.... what performance modifications have been done to your bike?

[masterofinsanity]

mine went pop at 16k if memory serves me right.

[Jamz]

mine went pop at 16k if memory serves me right.

Kin ell 16k???

I wouldn't have thought the head gasket would get weaker with age? So if you've got a bike that's been stood for 20 years with 3 miles on the clock, that wouldn't affect anything to any measureable degree?

One problem here could well be that some of these bikes were raced on track - so the speedo was almost certainly disconnected, meaning when it's back on the road and sold on it's reading a fair bit less...

Mine went around 30 - 32k I think. It was well looked after, had only a full Micron system that I'm aware of, but was used very hard every day - including cruising at around 110-120mph on motorways for a few months up to 9hrs a day!

In fact, come to think of it, it may have been nearer to 40k when it went?

[RedexRobB]

There were absolutely no mods to mine except for an end can that didnt require rejetting, which wasnt even on the bike when the gasket had gone. It had also been serviced not long before it had gone either, in fact it had covered just over 5000 miles before it had gone in for the service and none of the shims needed changing, it was all still within tolerance. The exact words from Mark at Bowen Moto were 'its obviously a good engine'. And i knew it was becuase it had a service history from the previous owner and had been fully serviced the day before i bought it too, then not touched again till Bowen Moto serviced it.

[zimm]

ive had 2 go, and seen 4 others go.. all between 20 and 25 thousand miles.

[rene]

not really bothered if it is a service item or not fact is they genraly go bettween 20-25,000 miles so you might as well change it

[RedexRobB]

not really bothered if it is a service item or not fact is they genraly go bettween 20-25,000 miles so you might as well change it

My thoughts exactly. Like i said it wont go at an exact mileage, but you can at least expect it to go within some mileage window of the bikes life if it hasnt already been changed.

[deviant]

fact is they genraly go bettween 20-25,000 miles

hearsay is they generally go between 20 and 25k. the point of this thread is to establish how close to "fact" that is. Story so far is only 6 people have actually admitted to seeing a head gasket go, so we've got a bit of waiting to do....

so you might as well change it

well I'm not going to deny you your right to faff around taking the head off a perfectly good motor. but you could change it when it would have gone on another 20k and the new one might pop in 15k...your call.

[mongo]

I would do it if the engine was dropped out of the bike already.... but then i know how to do them and have done them several times before. If you have the willingness to learn how to do it, its an ideal situation as well.

I would compression test it first though to check the condition of the engine first. One thing is though, as they do show signs going at a specific mileage (i notice age isnt included and not usually speculated?) but the gaskets will deteriorate with age, its a compact engine, it generates alot of heat. If the coolant is not kept in top top condition (right mix/changed over at right intervals) it can lead to the gasket going earlier.... but from teh three zxr engines i have had, all of them have had the gasket done on them, and they have always been 20k+ (one was 24k the other was 22k the other was 27k).

[Xphyral]

my 400 has 38K miles, is a 93 and head gasket is just fine, i've done over 16.000 miles on it in the 2 years i've had it, not many the last 6 months cuz it's just my little off day toy now. previous owner hadnt changed head gasket and it had only had one owner prior to that.

It may have had gasket done earlier in its life, i dont know. i've never really cared about it, if it blows it blows.

[zxr400@prodigy]

20,500 mine went i remember exactly because i had a rough weekend righting it haha.

[muffinman]

i had the lump out of the bike to get frame etc powdercoated, so i changed the headgasket then, at 25500 miles

it didnt go, but i thought i may as well do it, with changing the cam chain too

[tobomoto]

unfortunately mine was popped when i bought it. i done all the checks but i guess the dealer knew a couple more tricks. the fact that they motd it the day i picked it up with a 'not for road use' race can on it should have told me somthing. it had 20k on it.