Water Leak

[old son]

I have a very small water leak on my Gen1. The leak shows on the seam of the engine casing below the carburettors on the left hand side.  It is not obvious where it is leaking from. Has anybody else had this issue?

[old son]

The picture might be easier to understand the right way round. I can see a pink line where water has travelled but it seems to stop halfway up and no obvious place it is coming from. Thanks

[old son]

It is still showing wrong, turn clockwise by 90 degrees.

[FazThou]

There is a water pipe from the back of the head, you could check that first
It is just above the fins in your pic


You can see where the water has been running down in the third fin from the right

[b1k3rdude]

Is that location in the above image the only place there is coolant? I assume there is none around the cam cover or the spark plug galleries..?

 I would also check the lines running from the radiator to the carbs (these prevent the carbs freezing in winter afaik.

[old son]

I’ll check out the hose you mentioned, first thing in the morning.


There is no leak showing anywhere else around the engine that I can see. I will spend some more time with a torch tomorrow and report back


Thank you for your replies

[Gnasher]

I’ll check out the hose you mentioned, first thing in the morning.


There is no leak showing anywhere else around the engine that I can see. I will spend some more time with a torch tomorrow and report back


Thank you for your replies

Carb water heater hose/s and unions are the usual culprits in that area   

[old son]

I think the leak was coming from the outlet on the cylinder wall. I removed the pipe and expected fluid to run from the spigot. Instead it ran out of the pipe I had removed. Surely the water jacket around the pistons should be higher than the spigot level?

[Gnasher]

I think the leak was coming from the outlet on the cylinder wall. I removed the pipe and expected fluid to run from the spigot. Instead it ran out of the pipe I had removed. Surely the water jacket around the pistons should be higher than the spigot level?

Not sure what you're saying here?  Pictures would help

I've never known any serious problem with the cooling system on any Jap bike that's not been abused.  Leaks are 99.9% of the time hoses, unions/nipples and or the clips that retain them.  The surfaces of unions/nipples corrode over time and leak, or the hoses crack/split either due to age or owners/stealers pulling them off with too much force.     

[old son]

The pipe I removed was from a spigot half way up the cylinder wall. I expected there would be fluid in the water jacket to a higher level than the spigot.
The bike has done 114k miles and has started to run very slightly hot, often creeping up to 73 degrees whilst running at 50mph on a dual carriageway whereas it would always be closer to 68/69 degrees. I put this down to the higher mileage but am wondering that maybe there could be an airlock?


No sign of a leak anywhere else.

[Gnasher]

It's leaking that's why you've got coolant in the pictures you've posted, why the bike is running hot and why there's a lack when removing the hose.  You should also have an empty expansion tank?  You just need to find the leak

[old son]

I know it’s a leak!  The leak was extremely small so I know I’ve not lost a lot of fluid from it. There are no leaks anywhere else. I have now repaired the leak I have described.
I assume my assumption that the water jacket should have a water level higher than the spigot?
I have checked the expansion bottle and the level is on low.

[FazThou]

Top up the expansion bottle and also check the actual level in the radiator as well (when cold of course)
Clean up the old leak

Then run it for a while and see if you can see a leak anywhere

[old son]

Topped up expansion bottle, everything else seems to sealed and full. I've run the bike fir about 30 minutes with no leaks.

Thanks for your responses.

[kebab19]

I think the leak was coming from the outlet on the cylinder wall. I removed the pipe and expected fluid to run from the spigot. Instead it ran out of the pipe I had removed. Surely the water jacket around the pistons should be higher than the spigot level?

Do you mean the drain port hole half way up cylinder number one? I recall reading on the FZ1OA site about a few people who've had coolant dribbling out of there.
I'd been lurking on their site a decade ago as my first 1000 had major coolant problems due to a blown waterpump (was that way when I bought her, never spotted it till first long ride out).
When you say you ran her for 30 mins without an issue, did you mean running her gently or giving the bike some stick?  My old 1000 behaved fine until about 4000rpm then blew the coolant out past the thermostat cap once under pressure.

Hopefully problem will not reappear but keep an eye on her...

[Gnasher]

Only issues I've ever encountered/worked on with FZS1000's coolant system, other than union or hose failures is:-

Fan thermo switch failure, causing overheating in heavy traffic/hot weather.  This was mostly down to corroded connectors.

Fan failure due to over zealous jet washing.

Thermostat failure, very rare.

Blocked carb heating circuit, restricted rads and failed water pumps.  Are all in my experience a direct result of owners/stealers not using the correct coolant or when the system starts leaking due to union/hose failure they top up with just tap water or using no coolant just tap water.  The other is when the engine is worked on and the system not only is filled to tap water mix, it's filled incorrectly causing air locks. 

Tap water will and does rapidly cause corrosion even if the coolant is at the correct ratio, this rapidly turns into slit which buggers water pump bearings, blocks the cab water heater system and rad cores.   I've also seen cheap pattern parts fitted due the above mentioned fail in short order.

Basically there should be NO rust staining or coloured coolant, if there is the cooling system has had tap water added and the steel elements (water pump, elbows, unions and ridgited pipes) are corroding.

A well maintained engine/cooling system should use almost no coolant, if it is something is wrong.  Only ever top up (expansion tank) with either pre mix or concentrate coolant NEVER use tap water only demineralised or deionised water.  Only change the coolant if it fails a hydro test, the coolant on my FZS600 is the same that it was supplied with, I kid you not. 

As stated earlier and in my experience I've never known a jap bike water cooling system to fail (over heat) due to a design flaw, they if anything over cool. Requiring replacement thermostats to be fitted during recall or standard servicing, others GPz900R spring to mind had water temp senders replaced as they were rated to low and the temp gauge would go into the red at the hint of any traffic.  They went from black to pink or the other way around can't remember now.

     

[old son]

I've used the bike today and it was showing 65 degrees on the dual carriageway. I've never seen it that low!! Not showing a leak now. I wonder if it had a leak for a long time but was not obvious when the bike was switched off until last week? I've had the bike for 16 years and not had issues with water leaks and or overheating in the past.