KTM 640 Horrible engine noise!!!!

[Boon Booni]

Originally Posted by gunnerbuck

I'm wondering if those evenly spaced slot marks are put in on purpose to hold oil on the running surface? They seem too uniform to just be random machine marks...

The 640 does not have a small end bearing, instead it runs a bushing..

I was going to say it looked like a used con rod and those lines are brinelling.

Originally Posted by Kawidad

I believe its the Pro X rod he purchased.........

I meant to say "bought as 'new'".

[gunnerbuck]

Originally Posted by Boon Booni

I was going to say it looked like a used con rod and those lines are brinelling

Judging by the hone marks, it's new...

I have 2 new Pro- X rod kits, but they are already pressed onto my spare cranks so I can't check to see if they have a similar pattern on the running surface... I'm waiting for my OEM crank to start getting noisy so I can replace it but after 120,000 KM it shows no signs of this...

[moto_psycho]

There is no way in hell they are meant to be there, my best guess is that they are casting marks, towards the end of a casting run where things start to get close to their limit, then somehow snuck past quality control. Regardless I have returned for a replacement. Either that or the tool used to grind or hone the tool to size was damaged somehow, but I can't see why that would make the marks perfectly axial. Got to wait til mid next week before I can start putting her back together now :(

[gunnerbuck]

Hard to figure out where the marks came from, it looks almost like chuck marks from a lathe in your last picture...

What made the original bearing fail? Was it an interupted oil supply, debris getting into the bearing or just plain wear n tear? You said the oil pumps were fine, did you take them apart and inspect? There is a crank end seal is in the clutch case cover, be sure to replace that in case it played a part in the failure... If you inspect your con rod you will see a lube chamber inside the hollow pin, it is vitally important that the crank gets pressed together so the crank end oil feed passage is in perfect alignment with the oil feed hole in the pin... It is possible that some of the cranks were pressed together without full alignment of this oil feed resulting in a less than optimum supply of oil to the con bearings resulting in a shorter lifespan...

[moto_psycho]

The cranks will be going back together at the hand of a KTM dealer who has assured me they will press the halves back together at the same thickness etc etc...

My guess is that the oil supply was interrupted by cylinder base gasket failure causing coolant to mix with oil, thicken, and starve the big end. My reasons for this are that there was sealant compound on the base gasket, mayo in the original oil filter when i removed and mayo in the starter gear etc. The waterpump seal and shaft is fine.

[gunnerbuck]

Originally Posted by moto_psycho

The cranks will be going back together at the hand of a KTM dealer who has assured me they will press the halves back together at the same thickness etc etc...

My guess is that the oil supply was interrupted by cylinder base gasket failure causing coolant to mix with oil, thicken, and starve the big end. My reasons for this are that there was sealant compound on the base gasket, mayo in the original oil filter when i removed and mayo in the starter gear etc. The waterpump seal and shaft is fine.

The cylinder base gasket does not seal the waterjacket, it only keeps oil and engine pressure in ... The manual does call for a bead of sealant to be applied to the base gasket area around the cam tunnel area so finding some there is normal.. So if your passing coolant into the engine and it is not through the water pump then your looking at a faulty head gasket or a cracked cylinder head... It is possible for some moisture to leak in through a faulty starter O-ring but this is usually minimal staying in the starter area and should not be enough to effect the oil filter...

[bmwktmbill]

Moto, I blew a couple of head gaskets. It'seasy to see the problem upon dissassembly and if your gasket looks good I'd test the head using Gunner's technique.

If the head's good I'd at least rebuild/replace the water pump seals.

Are you redoing the valves?
bill

[moto_psycho]

The bike had clearly suffered from water when I first bought it. I had to ride it back 150 miles, then drained the oil, the screw on filter was filled with mayo. I had ridden it a fair amount since then, submerged it, thrashed it etc, no loss of water, and only mayo found was in the picture, an area of little to no oil flow. All drained oil was fine, except sparkly.

The head gasket and base gasket had sealant. Looking at the wear of things it appears to me that the engine had been stripped (sealent marks, minor pry marks) and judging by the state of the water pump it had been rebuild quite recently (barely any wear on the shaft, mildly tight bearings, and still red grease in seal). Water can still enter from a faulty base gasket, this is England after all, and the vacuum produced in the cases by a raising piston would be enough to draw in a droplet every stroke, I'm not saying this is what happened, but it's worth looking at every possibility.

The oil pump as far as I can tell is working fine, I cracked the oil lines off sequentially to ensure there was pressure before the rebuild.

And yes, I will be changing the valve seals possibly 2moro night, just need to get to my parent's house to steal a sunday roast and a spring compressor :).

[gunnerbuck]

Originally Posted by moto_psycho

The bike had clearly suffered from water when I first bought it. I had to ride it back 150 miles, then drained the oil, the screw on filter was filled with mayo. I had ridden it a fair amount since then, submerged it, thrashed it etc, no loss of water, and only mayo found was in the picture, an area of little to no oil flow. All drained oil was fine, except sparkly.

The head gasket and base gasket had sealant. Looking at the wear of things it appears to me that the engine had been stripped (sealent marks, minor pry marks) and judging by the state of the water pump it had been rebuild quite recently (barely any wear on the shaft, mildly tight bearings, and still red grease in seal). Water can still enter from a faulty base gasket, this is England after all, and the vacuum produced in the cases by a raising piston would be enough to draw in a droplet every stroke, I'm not saying this is what happened, but it's worth looking at every possibility.

The oil pump as far as I can tell is working fine, I cracked the oil lines off sequentially to ensure there was pressure before the rebuild.

And yes, I will be changing the valve seals possibly 2moro night, just need to get to my parent's house to steal a sunday roast and a spring compressor :).

I'll leave this thread to you, some where in here you did say you were a certified mechanic after all...

[moto_psycho]

I see where I went wrong earlier saying "coolant to mix with oil" my bad. But as mentioned prior, in my time owning the bike, I haven't lost any coolant, leading me to believe the previous owner may have fixed the problem (I am still looking for the cause!) I will remove the oil pumps tomorrow, if they are busted at 10,000 miles I will be severely shocked. I have the new water pump seal beside me, just waiting for rubber friendly grease to turn up. (why the hell doesn't the seal come with the athena gasket set!?)

It's pretty hard to find the source of a problem that doesn't seem to exist any more ha. But rest assured, every seal I touch I am replacing. I just can't be bothered to document / photograph everything as it has all been done before, and I am also not posting every single observation I note on here, thus I can understand my 'assumptions' may seem brash.

Gunner, can you tell me what "gunner's technique" is for the head test?

Also, I apologize that I appear to have upset you.

[gunnerbuck]

Originally Posted by moto_psycho

I see where I went wrong earlier saying "coolant to mix with oil" my bad. But as mentioned prior, in my time owning the bike, I haven't lost any coolant, leading me to believe the previous owner may have fixed the problem (I am still looking for the cause!) I will remove the oil pumps tomorrow, if they are busted at 10,000 miles I will be severely shocked. I have the new water pump seal beside me, just waiting for rubber friendly grease to turn up. (why the hell doesn't the seal come with the athena gasket set!?)

It's pretty hard to find the source of a problem that doesn't seem to exist any more ha. But rest assured, every seal I touch I am replacing. I just can't be bothered to document / photograph everything as it has all been done before, and I am also not posting every single observation I note on here, thus I can understand my 'assumptions' may seem brash.

Gunner, can you tell me what "gunner's technique" is for the head test?

Also, I apologize that I appear to have upset you.

I'm not upset, just out of ideas that seem to be of any help...

:http://www.advrider.com/forums/showt...=405073&page=2

[Boon Booni]

Originally Posted by gunnerbuck

I'm not upset, just out of ideas that seem to be of any help...

:http://www.advrider.com/forums/showt...=405073&page=2

Wow, you are a man with great patience. To have just redone the head only to find it faulty is truly a lesson temperament.

[bmwktmbill]

Errr...




bill

[moto_psycho]

Pretty cool, never realized that this was such a common problem...

... though I will take your idea and raise you a lazy point!

At work the metallurgists / quality control guys use dye penetrant inspection (when ultrasonic is not viable), basically you spray on an ultra low viscosity dye, leave it for a minute, clean it off, then spray on a curing agent. If there are any cracks the dye will begin to weep from the crack.

I know it is not as thorough as a high pressure test, but I have not lost any coolant since owning the bike, and I've had the fan cut in on tight trails many times, so I don't really suspect a head failure.

Is there a typical mileage this problem occurs at? Really starting to get a distaste for KTM now, never known a bike ot have so many "common faults".

[moto_psycho]

Oil pumps are fine, they turn smoothly, no visible damage.