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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Mark.r on March 24, 2024, 03:59:12 PM
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Hi,
I recently picked up a 94 k75s that was sitting for about 12 years in a garage. I have been going through rebuilding the brakes, injectors and fuel pump. I got to the point of giving it a start after flushing the coolant and oil change. When I tried to start the bike would not turn over. I had turned it over before when checking spark and ensuring it wasn't seized. When I removed the plugs there was coolant in the rear cylinder. My questions are:
1: has this come up before?
2: is it worth tearing in to the engine, and if so where so start?
3: Am I crazy being baffled that there is not coolant in the oil?
At least I learned to never pickup a bike without doing a compression test and just believe the prior owner.
Thanks in advance for the advice
Compression test
Cyl1: 150-155psi
Cyl2: 175-180 psi
Cyl3: 200 psi (the one with coolant)
Mark
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I was leaning towards pulling he head. Time to look at the manual.
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Are you sure that's coolant and not fuel with some oil mixed in? In that case it might be due to a leaking fuel pressure regulator.
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When I tried to start the bike would not turn over. I had turned it over before when checking spark and ensuring it wasn't seized.
Are you indicating the engine is seized now?
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It's coolant, the bike turns over now that I pulled the plugs and a bunch of antifreeze came shooting out when I cranked it over
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Hydrolock could be caused by fuel or coolant, but I'm not sure if you eliminated fuel as a possibility by some other means.
The compression is good, so that's not a bad sign for the head gasket.
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So I cranked it over this morning and after sitting for a week coolant came shooting out of the spark plug hole. It looks like it is either a cracked head or gasket. Should I try to get it running, or just go for it and remove the head?
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So I cranked it over this morning and after sitting for a week coolant came shooting out of the spark plug hole. It looks like it is either a cracked head or gasket. Should I try to get it running, or just go for it and remove the head?
Mark,
I would get it running if possible. If in fact you have a leak between the cylinder and water jacket it will buble into the coolant reservoir or blow out coolant if bad enough. At the very least I would pressure test the cooling system.
IMO taking things apart without doing a full diagnostic ends up expensive, frustrating, and often with unsuccessful results.
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+1 verify there's actually a problem internally before pulling the head. For one thing, with 200psi on the "wet" cylinder it may very well not have a head/gasket problem and the liquid is from some freak event & for another, if the head is cracked/gasket blown and it was run for any time like that there may have been glycol run through the engine and it may knock like a steam hammer when it fires up.
Either way would be wasted time, effort and money for you (one way you strip/reassemble and replace parts that were good anyway, the other way you spend all that time refreshing the top end and the bottom turns out junk. Get it spun over with no plugs until the cylinders are empty/no hydrolock, throw plugs in & go for a start. If it runs with no major pressing issues (geysers of coolant or rods attempting to escape) then check out of the gearbox/clutch works too and go from there.
Pressure testing the cooling system is a good shout too, might show up a leak in a silly place.
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There's a leak, that's true enough, but how do we know it's a coolant leak?
I think Caveman's advice is good, it's better to verify a coolant leak than to just rip into it.
On my brick for example the coolant is green, so if I saw a leak like that on mine, I'd go hmm, doesn't look green, what's it smell like. I'd look for leaking signs around the vacuum hose. If none I'd look for signs of dampness in it while cranking, or after cranking. Or bubbles in the coolant while cranking, stuff like that. This would only take seconds, and could save a bunch of time. The vacuum hose is on cylinder three, the leak is on cylinder three, coincidence, maybe.
I've fixed leaking head gaskets a bunch of times, where coolant was leaking into the cylinders, without removing the head. On all of those occasions it has always been on an outside cylinder, coincidence, maybe.
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I panicked when I found a puddle of green under my bike. Turns out it was a can of Mountain Dew that sprang a leak in my saddlebag. Compression was fine nonetheless.
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If I was looking at a brick that has sat for 12 years and I had no first hand knowledge of it....
I would not jump on the first symptom I find.
If it came with a death certificate and you want to preform a autopsy then please post pictures.
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Yes we can, but here's a thing. Was it yesterday that schrocketeer said his no start problem wasn't related to his starter spinning direction. You didn't trust that, I didn't, we were right. But I trusted everything else he said. Sometimes a man's gotta do what a man's gotta do, does that mean put your balls on the line and admit to something you don't want to? Schrocketeer did, bonus. Maybe there is another reason. What's wrong with spending ten seconds to verify that the fuel pressure regulator isn't leaking, instead of guessing it isn't and pulling the head?
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Is the clutch good? Driveshaft? Final drive? Is it charging? Instruments all work? Does it ride like a pogo stick?
Is there vibration in the engine? Does it make a knocking sound?
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Доверяй, но проверяй
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No not saying he doesn't know twice, but the question was ignored twice, this could be for a number of different reasons.
Colour? Bubbles? Smell? Moisture in the vacuum hose? Stuff like that. No special equipment required.
Four posters hunting for coolant leak to be verified.
An answer would be good (it's 2 30 am, getting up at 5, waiting for the weekend)
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3: Am I crazy being baffled that there is not coolant in the oil?
You aren't crazy being baffled. If it hadn't run in 12 years coolant likely wouldn't be flowing much without pump pressure. If it had been on the side stand most of the time during idleness, any coolant after its last run probably would remain above the piston because the angle of the engine when the Brick is on the side stand would have moved it toward the valves.
As far as the cost of testing equipment—leak-down or other—testing goes, any of that would likely be loaned by NAPA, Autozone, or some other big outfit, with only a refundable credit card deposit. I've taken advantage of that a few times with NAPA.
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I should have the head off this weekend. When I get it apart I will post some pics. Any tips on identifying a cracked head vs a bad gasket?
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Pay attention to the numbers on the cam bearing caps:
(https://i.imgur.com/aIyLa3j.jpeg)
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Easiest test would be to take a match to what is coming out of the cylinder. What does it say if the stuff doesn't ignite?
It would suggest that (if it is in fact gasoline) that it was bad from being 12 years old, or that (if it is indeed antifreeze) that it's not a very high concentration since Glycol is also flammable...
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OMFG! I'm done posting or even reading this thread.
How about listening to it as a podcast? Would that be ok?
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OMFG! I'm done posting or even reading this thread.
4265249878
But in all seriousness my original thought (and one I stand by) is that at least getting it to run/ride one could confirm viability of the project/potential cost of getting it up to snuff prior to dumping time effort and money into replacing the HG (or even the head too). I think that's where Caveman & daveson were also getting at.
I know it's highly likely to in fact be HG or head cracked (hell, even split liner worst case?), but if you're going to the effort of doing the head you might as well know whether your bottom end is any cop beforehand, or the gearbox/final/clutch/suspension etc etc etc. Just a small amount of glycol causes an engines plain bearings to fail in pretty short order as I'm sure you know given you have double my years around engines & given the lack of known history what's to say the oil wasn't changed/leaked coolant bled out the drain just after it started hammering? It was parked 12 years ago for something, more likely than they just stopped riding but held onto the bike...
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bitsa,
That is exactly what I was thinking. Thank you for putting it into words for me!
I am also very lazy and hate doing things twice or more. Half the engines that I have worked on have had other problems caused by being hydro locked. Mainly damaged bearings and/or bent connecting rods.
If the OP asked me to check the head and replace the gasket I would turn the job down. I pride myself as a mechanic and not a parts changer. I would however offer to sell him my 88LT that is in good running order but all fairing parts are damaged as well as right side peg plate broken and muffler skinned up for less $ than the head repair.
note: My son got his first 8-10K miles on a full size bike using that LT.
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Time for someone to say time out guys, we're all on the same side here, we're just trying to help Mark out, that's all, no big deal.
Come on Gryph try to understand what I'm on about, I never asked for a chemical analysis. What I was looking for was a comment like, it's green like my coolant, or it smells like coolant, or something like that.
Before I posted the recent schrocketeer question I thought I hope this doesn't come across like a suck eggs comment, and you helped me with that, but even so he felt he had to swallow some pride. Maybe my English was too sloppy this time.
Mark please believe me this was a genuine question with no intent to offend. You did say thanks for comments, well that was mine, given for free, with the slim hope that I might be able to save you some time.
Gryph, please don't stop posting, I don't think it's fair on Mark, let Mark sort the wheat from the shaff, I think he already has.
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I have been around engines for about 65 years now, and in my experience it is pretty hard to mistake gasoline for glycol antifreeze.
Therein lies the problem. You couldn't but many could. Most of us riders aren't mechanics. Many of us don't have much mechanical skill and aren't good at this, including myself. I think you know more than 99 percent of people here, and I'll never know one percent of what you do about mechanics.
Here's where I was coming from. Over here at least, petrol (gas) is usually red, but sometimes it's colourless and looks like water. Some riders would look at a leak like that and say water, I must have a coolant leak.
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Time for someone to say time out guys, we're all on the same side here, we're just trying to help Mark out, that's all, no big deal.
Come on Gryph try to understand what I'm on about, I never asked for a chemical analysis. What I was looking for was a comment like, it's green like my coolant, or it smells like coolant, or something like that.
Before I posted the recent schrocketeer question I thought I hope this doesn't come across like a suck eggs comment, and you helped me with that, but even so he felt he had to swallow some pride. Maybe my English was too sloppy this time.
Mark please believe me this was a genuine question with no intent to offend. You did say thanks for comments, well that was mine, given for free, with the slim hope that I might be able to save you some time.
Gryph, please don't stop posting, I don't think it's fair on Mark, let Mark sort the wheat from the shaff, I think he already has.
Here here, don't go just because (I presume) you had a bad day. I know I did reply with what could be construed as attitude via my flammability comparison, but you must admit that your attitude wasn't the greatest also? And that was what triggered my retort. I'm not trying to bash on you man, you're a respected member here and way more brick experience than I'll ever have just, we're all trying to collectively help to avoid wasted time/funds when the engine could be junk even with a new head.
Seriously hope you've not taken too much offence at what was said on my part, was intended more as banter/"shop talk" than outright questioning your experience!
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TMG,
Sorry if it was something I seid. I know you are dealing with other sh!t, please don't let it get you down.
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TMG,
Sorry if it was something I seid. I know you are dealing with other sh!t, please don't let it get you down.
I wasn't aware, not being a regular, that TMG had (more than normal) "behind the scenes" things going on & put it down to a bad day. Apologies again if I've upset you, kinda feel bad now.
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Hi Everyone,
It looks like I missed a few things while on travel for work. I want to thanks everybody for their input so far. I decided to pull the head. Partially because I had pulled so much off prior to getting everyone's replys and partially because it's gonna have to happen anyway. This is where I am now, for better or worse.
When I dropped the exhaust it was full of antifreeze, so it must have been a pretty serious leak, and kind of explained where it all went.
I got the head off, without too much headache, but something seems off to me.
when I loosened the last head bolt is just fell off the block. Not my normal experience removing a head. The gasket cam of easily as well which was also something I am not used to. Maybe it's because it's a bike, a bmw or I don't know, but in my experience with small engines and automobiles they don't come apart this easy.
Anyway, all the head bolts were tight and required a good amount of effort to loosen. So most likely they were torqued properly???
Also does the wear pattern look like the pistons have been honed recently or is that how these bike wear?
Attached are photos of the head and block. I am sure some good points will be brought up in the next few days. Thanks for your input in advance.
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Pics
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Ware pattern
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Good to hear the head bolts all came out okay. I wasn't that lucky with mine.
The hone marks in the cylinders were done, I believe, before the Nikosil coating was applied. The coating is so hard that they are still visible in engines that have a lot more than 100,000 miles on them. They hold the oil and reduce ring wear.
My eyes aren't good enough to comment on any of the photos. Have you looked at the head gasket and the head for signs of where the leak might be? It may be necessary to look in the exhaust port as well.
Do you see any signs of cracks or pores in the head casting? How are the surfaces of the block and head? Look carefully at the wall between the #3 cylinder and the coolant passage in the block. Are there any unusually clean spots on the block and head mating surfaces?
Worse comes to worse you might need to have a machine shop check it just to be sure there are no stress cracks that open when the head is torqued.
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Have you been able to check the surface of the head for flatness? Is it possible the head is warped?
What was the coolant level when you first got the bike? Are there any signs it was run with low coolant? That could allow the engine to overheat enough to warp the head.
As far as the condition of the cylinders, pistons, and head, they look like my K100 did when it had about 90,000 miles on it and ran great. The only problem it had was that it was using a little more oil than I liked. Turned out that synthetic 10W30 likes to sneak past the rings a little more than the 20W50 BMW recommends.
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What does a machine shop look for? I can bring it in to work and run a dial indicator across it in the mail if that will tell me what I need to know.
Edit:
When I got the bike the coolant level was below the head. It had been sitting for 12 years or so.
I will try to do a closer Inspection tonight.
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Machine shops have ways to test for microscopic cracks you can't see with the naked eye. A good magnifier will do at home. A good steel straight edge across the surfaces can tell you if the head is warped.
What does the head gasket look like? Are there signs of coked up oil around the valve springs and cams? That would be a sign of overheating.
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No cooked up oil. The gasket looks ok??? It was wet for sure. I am still amazed how easy the head came off.
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I was surprised the number three exhaust valve looks like the other two, thought it would be washed clean and more white. I'm looking at a small phone screen.
My spare K100 engine also has the same hone marks.
Here's another bit of unlikely wishful thinking. I wonder if the previous owner removed the head, and said this is beyond me, I'll put it all back and sell it. Because I'm selling it, I'm not buying a new head gasket. If you reinstall an old, compressed head gasket to normal spec, it might just leak, probably not that much though.
I would phone the previous owner and say thanks I'm very happy with the bike, could you help me with a bit of history about it, any work you did, any work you got done.
Inlet valve three is cleaner, piston three looks like it has more carbon, just saying.
One of the things I've done in the past to stop a leaking old head gasket, is to torque the bolts to just three foot pounds more than spec. But not once removed though. You wouldn't think three foot pounds could make that much difference, but it can.
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Mark,
Thanks for the pictures. Unfortunately I have little to offer.
Did the heads on the head bolts look like they may had bin removed previously?
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Caveman is there much merit in what I'm seeing, do you think? If it overheated then a coolant leak in cylinder 3, shouldn't that cylinder be looking much more clean than the other two? All three cylinders look wet. Let's say it wasn't leaking then the gasket was removed then replaced, then all three could be wet, and cylinder three more so. Bit of a long shot, yes.
We don't know if the head is warped yet, that could change the story a lot.
I'm also interested in Gryph's and bitsa's thoughts about this, and Mark's.
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Agreed it doesn't look like it's run for any real time with the leak, and given the rate of the leak I'm wondering if it is indeed something that occurred since last time it ran.
Mark, do you recall when you first looked if there was antifreeze/coolant or plain water? Another possibility being it froze and cracked something.
I do like the used gasket theory, but then why would they bother torquing everything down if they threw it together?
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Machine shops have ways to test for microscopic cracks you can't see with the naked eye.
One of the ways is explained at this link to the ASE website (https://www.freeasestudyguides.com/cylinder-head-inspection.html). ASE—not to be confused with SAE—is the abbreviation for The National Institute for Automotive Service Excellence. The jury seems undecided whether to have Excellence is our last name as a slogan. :laughing4-giggles:
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I do like the used gasket theory, but then why would they bother torquing everything down if they threw it together?
Wishful thinking, I suffer from it too.
He might say if it doesn't work, I'll sell it as a parts bike.
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Depending on how this goes parts bike is not off the table ...
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Previous owner may have pulled the head, didn't see any obvious damage and after doing a quick look at the head gasket decided to retorque the head with the old gasket.
I would still recommend checking the head for flatness using a steel straight edge. A good cleaning and a check for cracks is also a good idea.
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That will be my next step. I'm going to clean it tonight, and check it at work tomorrow with a granite slab and inspection camera.
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Great! I was going to suggest finding a surface plate to check it.
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Caveman is there much merit in what I'm seeing, do you think? If it overheated then a coolant leak in cylinder 3, shouldn't that cylinder be looking much more clean than the other two? All three cylinders look wet. Let's say it wasn't leaking then the gasket was removed then replaced, then all three could be wet, and cylinder three more so. Bit of a long shot, yes.
We don't know if the head is warped yet, that could change the story a lot.
I'm also interested in Gryph's and bitsa's thoughts about this, and Mark's.
Every blown head gasket or cracked head I have dealt with was easy to see when disassembled. Now water cooled intakes or porous wet liners not so much, but I have never pulled down an engine that has not ran for several years without intending to do a full rebuild.