Carnage in cylinders (pic intensive)

[IhmeJanneFIN]

A little intro for the pictures I took of my friends bike during dismantling. Pictures are pretty big, but you can see better.

My friend has a -93 Suzuki GSX 750 F, (Katana in USA). Well it had only ~38500km, which is about 24 000 miles when it broke down. He accelerated in the city and started to slow down to stop at traffic lights when it shut off and made some clanking noise along the way. Started very hard and it sounded like it was firing at only three, but no other side sounds (have had some sort of high pitch metal sound many times earlier, but sounded like it was coming from gearbox, or so we thought atleast)
He got the bike to my garage and I started to work on it. First I checked the plugs, rebuild the carbutetors and was still firing at only three cylinders. At this point we feared the worst and that there was something wrong inside the cylinderhead, (valve adjustment screw or something else had come loose).
I opened valve cover, everything seemed fine, checked and adjusted clearances (they were pretty OK), and then we realized there had to be something wrong inside the cylinder. I took all the plugs out and tried to look inside but didn't see anything. Then I tested if there was any compression on the cylinders by putting only one sparkplug on at the time and rotated the engine. I could hear some sizziling from 3/4 cylinders so it came clear there wasn't any compression on cylinder #3.
Well, at this point we decided to take the head off. We spent about an hour just to get the exhaust out, the bolts were very well rusted to the head, but we managed to get them out without stripping any threaps or bases.
Head bolts were also very tight, had to use lots of muscle power to get them also loose, but we managed to get the head off after much of cursing and sweating. Then it was clear, we were going to need new pistons and cylinder block because piston #3 had lost few pieces. But, this wasn't the only cylinder, 3/4 had marks on the head that piston ring pieces had hit them (and there was also those pieces stuck on the head).
We found "new" set of pistons and cylinder block, and as I was pulling the old block of and the pistons this destruction was discovered.

All the parts on the table.


Cylinder #3


More of cylinder #3, huge grooves


Head


Head at cylinder #3, you can clearly see the piston ring chips lodged in


Pistons out, left to right, 1,2,3,4


Piston #1, piston ring pieces on top of each other


Huge hollow on piston #1


Piston #2 hollows


Piston #2 top


Piston #3


Another angle of piston#3 (right side)


Piston #3 (front)


Piston #4 hollow #1


Piston #4 hollow #2


Piston #4 from top


Cylinder #3 grooves


Head #3 and pieces I took out


There is also some problems with the intake valves at #3. We are trying to find a machine shop that is not on summerholiday to check if the head can be repaired.


But does anybody have any idea what could have caused this kind on carnage on the engine? Running too lean, oil problem or what? Bike have had some sort of running issues now and then, but it have always seemed like carburetor issues as it has cleared when I have rebuild carbs. Btw, bearings at crankshaft are ok, there's no play on them.

Other pics of the bike engine http://s1071.photobucket.com/user/Ih...?sort=2&page=1

Janne K

[Kreylyn]

Well, just one thought...

In theory... liquids in the cylinders when starting/running the engine can/will cause things to break. loose parts then become carnage that do all sorts of things in there if the engine continues to be run.

Carbs on a Kat can cause fuel to leak into the cylinders. This doesn't always cause a full hydrolock issue where the engine stops... but it could cause breakage.

Not saying that was it, but you asked for ideas. That could be one.

Krey

[steves]

Something caused the metal piece to fail/break free. Lack of oil?

[GSXFJim]

That's a lot of damage. Other than the obvious top ring failures, the deformation of the piston suggests overheating and possibly a pre-ignition/lean condition at one point. I've also seen pistons that have come from engines that have been started with start fluid repeatedly, ether is bad for cylinders. See if the cylinders are out of spec (diameter).

[scottynoface]

Holy shit...looks like poor oiling, that's impressive something obviously rattled around the cylinder. Check the oil and see what kind of chunks came out. Only 24k miles? That's not much at all unless the bike was beat to death.

[shpielers]

Wow. I've had a top end grenade on me before when a rocker arm broke - took out the timing chain gear, timing chain, several other rocker arms, and marred one camshaft - but the pistons and cylinders were still ok.
That is some impressive damage.

[suzuki99]

I would have to say, lean condition but low oil levels come to mind aswell. How was your oil level? Do you check it every time you ride?

[BIG-KO]

I looked at your other pics on photo bucket. On like the last page you have a pic that shows the engine case still in the frame of the bike and the back side of the oil cooler looks like brown with road dirt. I cant help but wonder if the backside of the cooler is that dirty then just how dirty is the front of the cooler. Perhaps the oil cooler is so packed with dirt and it's now so ineffective at cooling the engine. These engines rely heavily on cooling the oil that if using a poor quality oil and too much heat could cause an oil breakdown. Also too much heat will cause pre-detonation on an overly hot engine and stresses parts to look like a meltdown. In a car it's much easier to hear pre-detonation or "pinging". On a bike at speed with a helmet on nearly impossible to hear. The pistons on top fuel dragsters look like this when running too lean or with too much nitrous, the tops of the pistons just melt, then all hell breaks loose like in your case.

[KATANA-BRASIL]

I'm not expert in engines like katlegend users but in my opnion this is low oild level dure the pistons situations I suppose that if had gasoline you could have problems with rods.
Anyway now its don't make so much difference since you have to repair your engine

[Wild-Bill]

Big-KO's idea makes sense although the oil cooler looks OK to me in the photos. Lots of bent fins but nothing too awful. Might want to try blowing out the cooler and straightening the fins before putting everything back together and if you find any restriction in the cooler then you've found your culprit.

[GSXFJim]

I don't think low oil levels would cause an isolated failure like this. If lack of oil pressure/volume was an issue the damage would be wide spread through out the engine, the main and conn rod bearings would most likely go first as well as scuffing of the cam bearing surfaces and valve guide damage.
Pre-ignition/detonation overheating is tough on pistons.. I think that's your culprit.

I also looked at the rest of the photos and the valve train doesn't show any signs of oil starvation, overall it's pretty clean. I'd be curious to see what the conn rod bearings look like.

[IhmeJanneFIN]

My friend have regularly checked the oil level, because all the time he have had the bike (this is 3rd summer), it have lost some oil during summer. I don't know have the engine burned it or has is it been blown to air box and drained to ground, because it is always very oily, or has it been doing both?

I checked cooler today and it is little muddy, but not that much, it's just a little layer on top to give it the brown color, but we will clean it anyway.

All rods are OK, so at least below the pistons has been good lubrication, no blue color or play anywhere and the rods were oily when I took block off. And also there was good oily layer on head also, and when we turned the engine it always started to drip oil from the oilpipes that go to the valve cover.


We don't know anything about the previous history of this bike and how it has been treated and maintained (no service book) or on what kind of mixtures it has been running earlier, but there has always been some trouble with this bike time to time, so I think that the top rings have been broken already when he bought it.
Oh, and the bike is imported from Germany, so no idea how much throttle turning action she has acquired there, (but so is my own bike too and she's running good at 20500 miles.)