ST1100 Pan European - long time dream (crippled) came through - head gasket?

Hi all, I'm new to this forum, to you guys and to my Honda, my only ride lasted about a foot in 1st gear inside the garage, but I couldn't resist not to do it and after finishing one foot of a distance I love the feeling. Will probably go ecstatic after going the first mile when it's all good... )


Here's the story - I bought myself a knackered (supposedly) 1994 ST1100 with 100.000 miles on the clock (would not be able to afford a proper one at this point and I should easily get the money back on it in case of a disaster as it's in really good condition) - the head gasket is leaking on it - yet I've seen traces of water around the top of rocker covers (no coolant / water standing in plug chambers), feels strong (well, never rode one and it was 1st gear, so 125 would feel strong...), will check water levels and attempt a short run (one circle round the block to check other mechanics on the bike). Yet - here's the photos of what I've seen on the bike, you can tell there's a leak but I wouldn't pin point it to a head gasket. Will do compression and / or a leak test and post results. I've seen cases with left side head problems, this is on the left side so it might be that, but have read a lot about pipes bursting on top of the valley pan and that (hope so...) could give coolant leaking from the top of the engine? Haven't seen the internals yet so only assuming - here's the pics. Any ideas / info appreciated. Will try to get the compression test as soon as I can. If need be, I'll strip the heads and skim - will need to do the belt same time, so I am hoping it can be resolved without heavy artillery, but will see.

Here is one your neighbors from Swansea, riding my ST1100 here in America. His name is Mike Cam.

aquilaalba said:

I'll strip the heads and skim...

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Not convinced about a blown head gasket, I'd check/fix/eliminate all other items first...
Remove false tank, air box and carbs to get access...

More than likely a leak in the valley... possible hose or elbow fitting.

Will try to strip the top of the bike later on today, also will do a compression test, yet it might be pointless as there (apparently) is no oil in coolant and vice versa - will double check that as well. Will need to take fairings off to see better, then clean the stains and start it to see where exactly it is coming from. Had an oil leak on a Suzuki GSX600F, all engine covered in oil, seemed like a massive leak - after cleaning it up turned out to be an alloy washer instead of a copper one under a bolt with oil channel inside it on top of the rocker cover, was already quoted around ?300-?500 to get it fixed...

aquilaalba said:

...there (apparently) is no oil in coolant and vice versa...

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More evidence against a blown head-gasket... such would also let exhaust gasses out the coolant expansion vessel (that "steam-lokomotive" like fume-steam-coolant spray emitting out the overflow at the RHS of the rear wheel is kinda noticeable... ;-) )

vinny said:

More than likely a leak in the valley... possible hose or elbow fitting.

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Elbows and hoses likely. That was my problem. Be sure and get NEW elbows even if the old ones look servicable. The castings seem to crack after a time, maybe because of thermal cycling.

2turbos said:

Elbows and hoses likely. That was my problem. Be sure and get NEW elbows even if the old ones look servicable. The castings seem to crack after a time, maybe because of thermal cycling.

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Or cracked hoses at elbows, etc. , etc.

+1 on the elbow/hoses diagnosis, even if they're not bad, they're ready to be replaced anyway if they are the originals. Not expensive, and will rule out one common coolant failure point..

also, get new carb boots, they're cheap too. There's also a hose at the front of the carbs that was really stubborn when I changed mine, had to mangle it a bit to get it off. Order one of those just in case.

Here's the photo without the skirt - few hundreds bolts later - didn't manage to get the carbs off yet to see what's up with the hoses / elbows. Leak looks odd though, anyone seen anything like it? There is something that looks like a hole that's got some sort of leakage - any ideas (second photo)?

Dare we say that this (second photo) looks unnervingly similar to the cracked block "syndrome" that has been raised on this forum before?? Sure hope not!!

First I'd carefully clean all up, fix the obvious leaks (elbows, internal passages, bypass, etc...), then check for any other issues while having it idling/warming up in the shop.

Haven't read the rest of this thread, but the second picture is of the drain hole for the spark plug recesses.

Edit: hose R&R and part numbers info: http://www.st-riders.net/index.php?topic=3523
+1 on buying the big air suction valves hose on the front of the carb body.

John

Not quite sure what to say with that last photo - looks like someone chamfered a hole. What's underneath that yellow stuff below that hole?

Edit: Unless I read John's post above mine which says it's a plug hole drain. If it was weeping out of there owing to a leak and a PO plugged it up, that could be why there's corrosion at the top of the valve covers around the plug - the chamber might have filled with coolant?

I can confirm that the hole is not plugged, also it doesn't seem to lead to plug well, as when I was shining light at it there was no light coming through in plug well, also it was the leaking point (later on this) and there was no fluid inside the plug well.
I was at it again, but didn't want to take carbs air filter / carbs off yet as last time I've had it running it died and did not want to start, so I wanted to confirm that it is still in running order, filled it with few litres of fresh fuel and tried starting. It did start after a while, was rough but after a while it did start to run properly. I have found an oil leak from the right side rocker cover gasket, but won't do it until rest is sorted anyway. Back to the issue. It was running correctly and smooth after few mins, revved nicely and all. There was no leak present at the time. I let it run watching closely for leaks, also expansion bottle top was off to see if there are any bubbles - none, flow present as it blows bit of coolant back when throttle is open - flow speeds up and settles after closing throttle. Seems ok. After it got to about 1/4th of the temp scale (just over cold part, on normal range) it started to leak a bit from the hole on the side of the cylinder. It seems that it is leaking only from there, not from the block / head gasket / etc. It was a very slow leak to start with, but as it warmed up it was increasingly seeping through. Did check the right hand side and there is same kind of hole on the side of the block, no leaks coming from that one though. Please see photos. I'll be back on it today and will strip the carbs to confirm what is the situation regarding leaks in the valley pan / on other pipes. That hole was there for a reason though and it seems there is something behind it that is prone to leak, hence that duct was made? Also, as it started to leak it started to run a bit rougher than previous, or it might be me. Any ideas?

Right, tank came off, can't seem to find the bolt to undo on carb #1, managed to undo the other three, but can't seem to find this one, hence can't take carbs off yet. Photo of the valley pan shows a bit of a problem there, I guess.



PS: Just managed to see the invisible bolt, it's now loose but here comes the fun part I guess... They wouldn't move, so will read more on carb removal and throttle cables need to come off as well. Next stop - exposed valley pan. Hopefully...

Seems more like a blog now - took the carbs off, leaking from both pipes - one question that I've got - do you only change the hoses or do the cast elbows actually can go wrong themselves? I was planning on taking them off, cleaning, inspecting and reusing them with new o-rings and new hoses - if not, if I need to have them replaced - do I replace the lot with bolts as well?

Definitely replace the elbows. They are a weak point and may appear good, but there have been reports of them cracking after a repair of the hoses was completed. Bolts should be OK after cleaning up the threads.

One of the elbows fell apart during removal, hoses were leaking and one elbow was definitely cracked - one with a pipe holder attached to it - on the right side. Elbows ordered, will see if hoses can be made to shape or order genuine ones and will finally put it back together. Fingers crossed. Sod's law - my MOT runs out in a couple of days...

Hi all, bit of an update, I've fitted new elbows, decided to keep old hoses, etc. just to check that everything else works fine before I start spending more. As for the leak from the hole at the back of the cylinder - on close inspection of the other side it turned out to be not drain for spark plugs but core plug location, which explains the coolant leaking from it - correct me if I'm wrong, but there was nothing in the sparky well and coolant leaking out of the hole. Anyway, for now - plugged with some chemical metal, can be drilled back to way it was but no leaks now. I've got another problem, as it is misfiring (one of the rubber boots on the carbs is loose on the inlet side, but will get back to that on cleaning and synching carbs after all the rest is good) but main problem is that it started to warm up more than I'd want. Didn't overheat, but went around 3/4 of the gauge - temp drops when engine is revved or moving. Will need to change oil and plugs, as not sure when it was done last. Apart from that it was hard to change gears until oil warmed up, still bit of an issue when cold, oil change should sort it out. As said, been standing for about six months with me and probably before I've had it. No more coolant leaks now, bit of an oil leak from right rocker cover but nothing major. Might be the thermostat as it was standing and might be stuck, might also sort itself out - will take it out tomorrow, was supposed to be MOTd but not sure if this will happen in this case.