ZZR250 overheated, blew head gasket

[imthatguy]

Sup guys, First post!

So yesterday I was heading up to Taupo from Palmy, my bike overheated and is now acting like an expensive piece of scrap metal.

Heres the story; It was around Taihape area when I first noticed it was down of power, but as it was nearly out of fuel I switched it over to reserve and thought nothing more of it (that may or may not be related).

About 100m out of Wairuru the bike began to smell really hot and developed what sounded like a knock so I pulled over into the Z station as I had to get some fuel anyway, just as I pulled up next to the pump, the bike stalled.

To my horror I discovered the last dregs of my coolant spewing out everywhere from the water pump area, I soon realised this was because the bolt that holds the inlet pipe into the water pump, had somehow worked itself lose and the inlet pipe had been happily pumping coolant onto the ground!

I went inside and secured some tools which I used to reattach the pipe with another bolt I temporally pillaged, then I tool the faring off over the radiator cap and proceeded to pore cold water into the radiator - probably shouldn't have done that as next thing I know theres an enormous cloud of steam and more coolant on the ground! On closer inspection I discovered this was coming from the front of the engine just under the exhaust headers.. Oh dear.

It won't start now (bit of a given really..) and while the radiator cap was off I noticed that when the engine was turning over it was bubbling the coolant which isn't a good sign.

Sooo anyone have a rough idea what Im up for a new head gasket?
Also what do you think the knocking noise would have been?

Cheers guys,
Aaron

[tri boy]

If you noticed it was down on power a while back, (even a minute or two) and kept riding, then budget on a topend rebuild. ie rebore, pistons/rings/gudgeon etc, plus probably valve/seat damage etc.
Strip an inspect.
It probably won't be cheap

[imthatguy]

If you noticed it was down on power a while back, (even a minute or two) and kept riding, then budget on a topend rebuild. ie rebore, pistons/rings/gudgeon etc, plus probably valve/seat damage etc.
Strip an inspect.
It probably won't be cheap

Well to be honest Im not sure it was that I could feel, as I said it was genuinely low on gas, and it seemed to correct itself after I switched to res..

Would something in the top end cause the knock?

As it happens I actually have another motor sitting in my garage I took out of this bike ~3 months ago for an unrelated issue, so hopefully I can pillage some parts off that. Otherwise another engine isn't really the end of the world..

[tri boy]

Spare engine might just save you a bucket load of dosh.
Strip an check anyhow.
If your knowledge in such areas is limited then seek help. A "can do" effort could cost. mho.

[imthatguy]

Spare engine might just save you a bucket load of dosh.
Strip an check anyhow.
If your knowledge in such areas is limited then seek help. A "can do" effort could cost. mho.

Unfortunately I don't know anyone else who can help, but Im confident I can work it out.

I bought this bike as a project to learn about/on, would be nice to be able to actually use it at some point though.. ;)

I have exams right now, so it will have to wait - Ill strip and inspect after and report back.

Thanks for your help!

[mossy1200]

http://www.trademe.co.nz/motors/motorbikes/parts-for-sale/complete-engines/auction-797286650.htm

[imthatguy]

http://www.trademe.co.nz/motors/motorbikes/parts-for-sale/complete-engines/auction-797286650.htm

Are you insinuating?? ;)

I decided this is much more interesting then study, so I've got most of the head off, will let you guys know what I find.

[mossy1200]

Are you insinuating?? ;)

I decided this is much more interesting then study, so I've got most of the head off, will let you guys know what I find.

Hope you have a good eyeometer:blink:

[ducatilover]

I may be in Palmy area at some stage in the near future, I'd be happy to lend a hand :yes:

If it's properly cooked, like you describe, I would be avoiding using the engine at all. Chances are it's got hot enough to fuck the oil, and in turn the bearings, rings, etc.
Why did you take your other motor out?

[imthatguy]

I may be in Palmy area at some stage in the near future, I'd be happy to lend a hand :yes:

If it's properly cooked, like you describe, I would be avoiding using the engine at all. Chances are it's got hot enough to fuck the oil, and in turn the bearings, rings, etc.
Why did you take your other motor out?

Hey thanks man! I appreciate that. Let me know when your down, Ive also got a fzr250 that needs the carbs cleaned if your interested? ;)

Understood, as I mentioned before it won't even start so no chance of that ;)
And its now in multiple pieces on my garage floor - had to get some work do so I've abandoned it for now, but Ill assess the damage tomorrow and decide on the way forward.

To be clear, I don't think it seized, exactly, I think because the head gasket went it just lost compression, thats what It FELT like anyway, time will tell I guess.

Well actually, I took it out because I thought it had also overheated haha (motorcycle noob as you can tell), though on closer inspection I failed to find much evidence to support my theory. The motor thats in there atm is much newer though, so if possible it would be nice to salvage it, if possible.

The original engine one would run fine until you hit 100kmh, then almost instantly you would lose power, it would start blowing clouds of white smoke, and it would very quickly seize and be un-turnoverable for 40-50minutes until it has sufficiently cooled down.

[The Reibz]

Chances are you have warped the cylinder head. Pouring cold water into it while its still massively hot may have also caused it to crack.
Buy the 2nd hand engine mossy posted.

[imthatguy]

Chances are you have warped the cylinder head. Pouring cold water into it while its still massively hot may have also caused it to crack.
Buy the 2nd hand engine mossy posted.

Fair enough, Im about to find out. What would be a telltale sign that the head is warped? I assure its more or less the same as a car engine?

Im not in a huge hurry to get this back on the road so will probably shop around until I find one for cheaper then that. The engine I have in there now I picked up for $300 with 30k on it and a months warranty..

[The Reibz]

Run a straight edge over it. If it's warped you will know

[bogan]

I'm in palmy, can provide second opinion as needed. Got a bunch of measury things (technical term) lying about that I can throw at it...

[mossy1200]

Fair enough, Im about to find out. What would be a telltale sign that the head is warped? I assure its more or less the same as a car engine?

Im not in a huge hurry to get this back on the road so will probably shop around until I find one for cheaper then that. The engine I have in there now I picked up for $300 with 30k on it and a months warranty..

I didnt mean any disrespect but if it was me idd chuck the second hand motor in and then rebuild yours as a project as you have spare money. Full rebuild, not just a temp repair or keep the spare bits as they will serve you in the future.
Its most likely from your op that you have a warped head so that will need skimmed and crack tested. Maybe new pistons and a oversized bore, bottom end rebuild new cam chain and sprockets if you want the best repair. The question is if you start a rebuild are you going to get your monies worth or are you going to upgrade to a larger bike in the near future. Your rebuilt motor wont fetch you a lot more if any when you sell or trade your bike. in fact idd say idd say running bike with spare motor as parts be worth the same amount in your pocket.

[ducatilover]

Hmm sounds like you have two shitheap motors bro. If your original one was heat seizing, I would pretty much put that in the scrap metal pile. Same goes for the second one really, but we can have a looksie at some point.
Bogan is bloody good at measury thingies, I highly recommend his help. He will even give you bike parts to polish for a few years

[ducatilover]

Blowing a headgasket on them is impressive, I am fairly certain they have a multilayer gasket on them and you'll find everything bends and warps before the gasket goes, I'd say you're more likely to warp the head and snap a stud before the gasket lets go. Or shift/crack a liner.

[imthatguy]

Hello again all!

Thank you very much for all your helpful replies, suggestions and offers of help!
All much appreciated.

To the people saying get a new motor, I totally agree that would be the logical thing to do at this stage, but I enjoy pulling things apart so theres nothing to be lost and experience to be gained in pull this one to bits.

I spent the afternoon in the garage, and after must frustration and swearing Ive managed to get the head off. (Pictures attached) Theres a few interesting things of note; the head gasket is fine, but there was water in both the pots (unfortunately cleaned up before I had the presence of mind to photograph). No visible cracks in the cylinder lining.
From what I could roughly determine with a metal ruler I had on had, no head warpage, but measuring with a ruler is a very inexact science and it will need to be properly measured. Anyway if its not head warpage I don't know how else to explain the leak..?

03ducatilover:
your quite right head gasket looks fine

01ducatilover /bogan:
Yeah Ide really appreciate the help, cheers! Flick me a text 0278633603, might take a break for a few days to study as I have an exam on Friday, but Ill be back to this soon..

08mossy1200:
No disrespect taken haha, I totally understood what you meant. And your right, Ive got a few contacts who wreck bikes so Im sure a new engine will turn up soon.
Would you really recommend replacing all that for a warped head? The engine is relatively new (30k) given the rest of the body is a 1990.. Seems a bit silly to spend so much on it. I was thinking maybe just a cylinder head plane and wack it back on! ;)

The Reibz:
I suspect your right.
304652304653304654304655304656304657

[mossy1200]

Idd suggest take head in and get advice that's not reliant on some photos on KB.
Me idd get skim and checked for warp. New piston and ring set one size over. Check bottom end for any issues prior to doing anything else.
Is that old im looking at or slightly wet radiator water?
Whats the oil look like also?

[The Reibz]

Atleast there isn't any catastrophic damage visible in the photos.
If you get the head skimed you will also need it die tested for cracks and pressure tested for good measure.
Expect to pay atleast $200

[nzspokes]

Atleast there isn't any catastrophic damage visible in the photos.
If you get the head skimed you will also need it die tested for cracks and pressure tested for good measure.
Expect to pay atleast $200

This is spot on. At a guess the cracks will be in the valve seats or under them. But I would strip and clean the head first and look for obvious cracks.

Or just buy a good motor. And do a good clean out of the radiator.

[imthatguy]

Idd suggest take head in and get advice that's not reliant on some photos on KB.
Me idd get skim and checked for warp. New piston and ring set one size over. Check bottom end for any issues prior to doing anything else.
Is that old im looking at or slightly wet radiator water?
Whats the oil look like also?

Oh the photos were more for interest sake then anything, I will ask advice from the a bike mechanic tomorrow.
Oil looks fine no water in it and its the right viscosity.
Not quite sure what your asking re water? Remember that I put water into it after it lost almost all of it due to the pipe leak..

[imthatguy]

This is spot on. At a guess the cracks will be in the valve seats or under them. But I would strip and clean the head first and look for obvious cracks.

Or just buy a good motor. And do a good clean out of the radiator.

Definitely no cracks I can see, but Im guessing they would be so small I wouldn't be able to see them? Will definitely give it a clean and check in any case.

Are you suggesting that would explain the fact its leaking OUT of the head? Or would simply be another consequence of the head being overheated.

[nzspokes]

Definitely no cracks I can see, but Im guessing they would be so small I wouldn't be able to see them? Will definitely give it a clean and check in any case.

Are you suggesting that would explain the fact its leaking OUT of the head? Or would simply be another consequence of the head being overheated.

No, thats why they use dye to mark where it is. You will need to clean the carbon off to have any chance of seeing unless its a big crack. And pull the valves as it could be in the ports or seats. I would say the head is cracked, you just need to find where. Couple of pics of the gasket may help to.

[imthatguy]

No, thats why they use dye to mark where it is. You will need to clean the carbon off to have any chance of seeing unless its a big crack. And pull the valves as it could be in the ports or seats. I would say the head is cracked, you just need to find where. Couple of pics of the gasket may help to.

Ahk gotcha, Ill get you some pics soon.

[bogan]

Theres a few interesting things of note; the head gasket is fine, but there was water in both the pots (unfortunately cleaned up before I had the presence of mind to photograph). No visible cracks in the cylinder lining.
From what I could roughly determine with a metal ruler I had on had, no head warpage, but measuring with a ruler is a very inexact science and it will need to be properly measured. Anyway if its not head warpage I don't know how else to explain the leak..?

I wasn't run-off water from dissasembly? If not, figuring out where that came from should be the focus imo, any water in the intake/exhaust sides of valves?

[imthatguy]

I wasn't run-off water from dissasembly? If not, figuring out where that came from should be the focus imo, any water in the intake/exhaust sides of valves?

Well I figured it came in because the head was warped? No the valves were all dry and relatively clean.
As I mentioned, when it broke down, the coolant was running out of the join between the head and the rest of the block just underneath the exhausts, I suspected if its warped its also running into the cylinders too, hence why they had water in them.

[imthatguy]

I wasn't run-off water from dissasembly? If not, figuring out where that came from should be the focus imo, any water in the intake/exhaust sides of valves?

Although actually come to think of it, it could well have been from disassembly as the engine is on a lean and there could have been water still in the coolant jacket as I pulled it off.

[bogan]

Although actually come to think of it, it could well have been from disassembly as the engine is on a lean and there could have been water still in the coolant jacket as I pulled it off.

Yeh, reckon that could be the case; which would take water out of the equation (but in a good way this time). So after it stopped from overheating, did you try and run it again once things had cooled? if so what were symptoms, compression etc.

[ducatilover]

Chances are the head is fucked. Usually with little Jappas like this the heads go soft after overheating and they go wobbly too. But worth having it checked if you really want to play with the motor (nothing wrong with that idea :niceone: spanner time is good)

You'll want to hone the bores and re-ring it. So you'll need a set of micrometers, feeler gauges and a decent vernier caliper. (probably cheaper to borrow), I hope it's a poor photo because that bore looks glazed and I cannot see any cross hatching at all

I'd pop the barrels off it and have a good look on the thrust side of the pistons for signs of seizing (nice tasty marking) which I imagine it has done. If it has, pistons are toast unless you want a hand grenade motor. Checking the bore size all the way down is nice and easy, just calculate it with the ring gap

You can buy forged pistons for these with a number of different compression and squish arrangements :cool:
Also if it has been seizing, there is a very, very high chance that it has damaged the mains and big ends, they're not huge fans of suddenly stopping.
The rods will have to be very carefully inspected too as they're very petite around the small ends and seizing never helps
And after going that far, I would be investing in some beer to pay a decent mechanic mate to split the cases, because you'll learn a lot if you do.


And that's just the beginning :2thumbsup

[imthatguy]

Chances are the head is fucked. Usually with little Jappas like this the heads go soft after overheating and they go wobbly too. But worth having it checked if you really want to play with the motor (nothing wrong with that idea :niceone: spanner time is good)

You'll want to hone the bores and re-ring it. So you'll need a set of micrometers, feeler gauges and a decent vernier caliper. (probably cheaper to borrow), I hope it's a poor photo because that bore looks glazed and I cannot see any cross hatching at all

I'd pop the barrels off it and have a good look on the thrust side of the pistons for signs of seizing (nice tasty marking) which I imagine it has done. If it has, pistons are toast unless you want a hand grenade motor. Checking the bore size all the way down is nice and easy, just calculate it with the ring gap

You can buy forged pistons for these with a number of different compression and squish arrangements :cool:
Also if it has been seizing, there is a very, very high chance that it has damaged the mains and big ends, they're not huge fans of suddenly stopping.
The rods will have to be very carefully inspected too as they're very petite around the small ends and seizing never helps
And after going that far, I would be investing in some beer to pay a decent mechanic mate to split the cases, because you'll learn a lot if you do.


And that's just the beginning :2thumbsup

Thats the spirit haha ;)

All great advice.

Just to clarify, Ive been though heat seizing before, as I mentioned this happened in my previous motor, it was characterised by an immediate sharp decline in power, up until it stopped completely, then it would be unturnoverable for 40-50 minutes afterwards while it cooled down.
This isn't what happened to this engine, apart from the fuel thing, I didn't really notice any loss in power until I pulled up next to the pump, then it stopped but it didn't feel like it seized, it just.. Died, like it would from running out of petrol (but not, because there was still petrol in it). When I went to try start it ~10 minutes later it turned over freely, just didn't want to actually catch and fire, like it was running low compression ( and the bubbled in the coolant as it was turning over would indicate that same). I would have thought that it it really overheated it would have exhibited the same symptoms as the original engine and not turned over at all, or atlas felt like it was rubbing..

Photos were taken on my phone in a dark shed, Ill do my best to get you some more tomorrow. It actually looks more or less ok from what I can remember..

Maybe Im just being unjustifiably optimistic, but, even if its completely toast as you suggest its still been an interesting exercise :)

Thank you for all your help!

[imthatguy]

Yeh, reckon that could be the case; which would take water out of the equation (but in a good way this time). So after it stopped from overheating, did you try and run it again once things had cooled? if so what were symptoms, compression etc.

Check page 3 haha :2thumbsup

[ducatilover]

It is pretty hard to fix motors on the internet sadly :( but I reckon it'll be a bit of a giggle for you. I'll let ya know if/when I come over that way :cool:

[imthatguy]

It is pretty hard to fix motors on the internet sadly :( but I reckon it'll be a bit of a giggle for you. I'll let ya know if/when I come over that way :cool:

Its the journey not the destination right? ;)

Sweet man, I appreciate it!

[imthatguy]

Its the journey not the destination right? ;)

Sweet man, I appreciate it!

Im about to head into an exam so this'll only be a short update, but Ive spent the last few days pulling and inspecting the top end and putting it all back together again.

I had the head planed as it was significantly warped. Somewhere (ill upload photos later) I have a photo from the machinist of the damage.

Pistons seemed alright and there was plenty of gauzing left on the bore, so I decided to put it back together and see what happened. Low and behold, after my throughly flat battery had been given some juice, it roared back into life!

All up the total cost of the rebuild has been about $80 not including tools ($250) and im going to change the oil/filter/coolant ($60).

Its anyones guess how long its going to last, ill saver my victory while it lasts ;)

Thanks for all your help guys!

[Bender]

Well done that man.

[BlackSheepLogic]

Just to clarify, Ive been though heat seizing before, as I mentioned this happened in my previous motor

There's a maintenance issue you should fix.

[imthatguy]

There's a maintenance issue you should fix.

This was, you understand, on the previous motor? Not on the one thats in there now. I will pull the head off the old one at some point and take a look, but this discussion was based around the new motor.

[ducatilover]

Well done that man.

+1 :headbang: