no compression at all either cylinder!

[edheiser]

two more nagging problems

Before I start on a course of action, there are 2 things I would like your opinions on.
1. The left lower cam chain blade came out when I took off the head and removed the front bolt/pin holding it. After looking at the schematics, it appears the other end should have been secured also with an Eclip/circlip on a shaft. I saw a video of it also with the piston and rod removed from a rusty engine. BMW says reinstalling it requires splitting the cases, the video said it was possible to put it on with only the piston removed.
Not knowing any better then, I reinstalled it as it came out, so it's just against the locating pin, perhaps on top of it. Funny, the front hole in the blade is oval and wide enough to locate it either way. Edit: actually it appears in the schematic that the other end has the oval hole in the blade, sorry.
This is a nagging worry, what do you think. Is it important enough to disassemble the whole motorcycle? It was obviously assembled wrong and had been running that way.
2. The lost cam chain tensioner piston. The original 17mm head tensioner piston slid off upon disassembly and fell into the case along with the spring. I was able to retrieve the spring, but the piston it MIA. I drained the oil in the faint hope it would come out, and peered and poked inside the case with a pick-up devise, no luck..so same thing, forget it or disassembly bike. So..........what do you think.

 

[23217]

If you broke the cam chain slide, it must be replaced before you can get the engine running. My guess is that is why it will not start. You may have also bent the valves on the left side too. I would pull the left head off to check. There is a way to replace the blade without spitting the case. Not easy, but it can be done. You will have to remove the transmission & clutch to get access to the pin. I would try to remove the transmission along with the drive train as a unit. It saves time. If you Google it, there is information on how to do this. Getting the metal cam tension piston out is also important.

Removing the engine and splitting the case is a lot of work! I would try to avoid doing it.

If it had the original cam chain tensioner, that may be why cam chain slide broke. Need to upgrade it. About $80

Each of these steps is a big project. Ask questions. If you don't have the BMW factory manual (in pdf format), I would look around to find a place to download it from. Or, you can get it from any BMW dealer.

 

[edheiser]

Long story again

If you broke the cam chain slide, it must be replaced before you can get the engine running. My guess is that is why it will not start. There is a way to replace the blade without spitting the case. Not easy, but it can be done. You will have to remove the transmission & clutch to get access to the pin. I would try to remove the transmission along with the drive train as a unit. It saves time. If you Google it, there is information on how to do this. Getting the metal cam tension piston out is also important.

Removing the engine and splitting the case is a lot of work!

If it had the original cam chain tensioner, that may be why cam chain slide broke. Need to upgrade it. About $80

Again, I know this is a long read, but I mentioned already that I have the new 15mm tensioner installed. I did pull of and reinstall the left head, no damage. Also, to clarify, the cam chain blade is not broken, Just installed without splitting the cases to put it on the second locating pin and install the circlip and possibly a shim also (still not sure about the shim for the engine) as I found it (supposedly in running condition).
None of this answers as to why in ran one day, and not the next and was found to have no compression in either cylinder due to skipped timing. Since it passes a leakdown test with flying colors, a valve is not closed somewhere on the compression stroke, but is closed at close to TDC to hold air in the leakdown test. I say close to TDC because the OT mark cannot be maintained in the center of the window because it springs past if you apply more pressure to make it advance.

 

[141987]

...PO said he rode to work and home, next day it wouldn't start...

So, if I understand the sequence of events correctly:

...You never actually rode the bike yourself, nor saw it running. The PO says he drove it home, it was running normally, he turned it off with the key, and the next day it wouldn't start...

One has to wonder what could happen to a turned-off, normally running bike, that, all of a sudden, would cause it to lose all compression in both cylinders overnight??

Is it possible that an animal climbed up into the engine overnight, chewed through the air filter, and left a fragment of a nutshell under a partially open valve or something like that??

It might be worthwhile having another conversation with the PO? Did he observe any unusual symptoms or noises on that last trip?

The Haynes manual for my bike (a 2011 R1200GS) lists the following troubleshooting ideas for low compression:

• Spark plugs loose
• Cylinder head not sufficiently tightened down
• Improper valve clearance
• Cylinder and/or piston worn
• Piston rings worn, weak, broken or sticking
• Piston ring to groove clearance excessive
• Cylinder head gasket damaged
• Cylinder head warped
• Valve spring broken or weak
• Valve not seating properly

The Haynes book expands on each of the above items.

It would probably be worth your while to buy the maintenance CD from BMW.

Good luck..

 

[dieselyoda]

At this point, you could do this:

Take one cylinder and loosen off the valves a good 0.125". Turn over engine, if it still snaps, then re-tighten the valves on that head and repeat on the other head.

If it still continues to snap over TDC, you definitely are going into the front cover. If it quits snapping on one side or the other, the side that quits snapping tells you the cam timing on that side is out.

My guess to mirror Anton's thoughts are the valves are hitting the pistons. This is occurring at overlap.

Something to skew all the theories here and mine as well if the cylinder heads have been surfaced below the acceptable minimum. At that point, you would have confirmed all your timing marks are accurate and you would need to pull the heads and measure their thickness.

One common "quick fix" to over cut cylinder heads is to either advance or retard cam timing so the lift on the valves is at it's lowest on overlap.

 

[edheiser]

Talked to previous owner just now

The previous owner is a very nice guy and told me some history. He bought it from a coworker and he bought it from a guy who was a "project" guy who did some or a lot of work on it after he purchased it from an auction.
He rode it to work, and after work, when he tried to start it, he heard a clink from the left side, and then it would just turn over but not fire. He had it towed home on a flatbed, and did nothing more than take off the left valve cover and look for obvious damage. Realizing he had no idea or much in the way of tools, he sold it. So at some point, the left lower cam slide was removed, replaced or somehow not assembled on it's inner shaft, and was attached at only the outer end. But it was ridden most every day for 1 1/2 years this way. If this had anything to do with it jumping time or not, I don't know.
Since I had the left head off, and let the cam sprocket turn on a big screwdriver shaft secured to the head studs with zip ties, while I tried to get OT to stop in the window hole (wouldn't) even after backing the right rocker adjusters completely off, I am going into the front timing cover next as Dieselyoda suggested.

 

[Gruesome]

Sorry about the problems you are having with this engine. I think the most important thing you have to do is to stop jumping to the next step and taking things apart before finishing diagnostics.

Anton and others described how to do a basic check of valve and cam position when one of the pistons is at top dead center between compression and ignition stroke. You don't need to see a timing chain or flywheel or anything else inside the engine for this procedure, which is why you do it first. Near TDC at ignition the valves/rocker arms on that cylinder are on the circular ('flat') part of the cam and do not move even when you are quite a bit off in camshaft angle in either direction. So, minimal disassembly and no precision required, which is why you start with this. It won't fix the parts you already broke or lost, but at least you'll know where you are.

 

[edheiser]

Progress

This morning I removed the 4 rockers and was finally able to freely turn the engine to OT in the window. Now I can finally see that the cam sprockets are not pointing where they should be, both are off 3+teeth.

so I'm taking off the timing chain cover next to see what's up.
Thanks again for all your comments, I think it's finally sinking in how this works.

 

[rxcrider]

Good deal and headed in the right direction from the sound of it. Be sure to lock the flywheel and check leakdown to verify all the valves are seating / sealing.

 

[roger 04 rt]

The sprockets being off by three teeth makes me wonder if someone installed Lennie's Rocket Sprockets incorrectly.

 

[pglaves]

This bike is a mess. Pardon my honesty. There are three cam drive chains. One goes from crank to countershaft, two more out to heads. Jumped teeth are rare, but possible - but then the question is why?

The repair steps include getting the chain from crank to counter shaft sprocket right and then the chains to the cams just right. And then there is that pesky guide that some yoyo installed wrong.
In the end it may work out fine, but in the meantime ...
The one time I battled a broken chain guide I pulled the engine and split the cases. I hope this case can be solved more conveniently.

 

[AntonLargiader]

When things are correct, I think you cannot lose the upper left tensioner piston into the engine. Are you sure the upper left rail isn't broken? I suppose if something was wrong with the lower rail maybe there would be enough chain slop that the upper rail could go too low, but I've never experienced this as a problem. Normally to install I just drop the new piston into the hole.

 

[edheiser]

Mess?

I prefer a challenge to the word mess, but yes, it's a mess. But I knew at the price I paid that it was a pig in a poke. But just to clarify, the left chain upper chain rail is not broken , I made a mistake when I disassembled it by taking off the cam sprocket before I took off the tensioner. I assumed it would come out as one piece, held together by a circlip like a rear master cylinder or something. Even the new 15 mm one needed heavy grease to keep it together to not fall apart. German engineering?
The lower rail was indeed assembled wrong, when is anyone's guess. But it ran like that for over a year everyday, perhaps since new. Actually, when it's assembled, one retainer bolt seems like all that is needed, there's nowhere for it to go, and it's held in place under tension of the chain. My CB750 cam chain guide just had one end retained, the inside end just fit under a ledge. So perhaps it's no big deal. I may find that's the least of my problems anyway. The errant tensioner piston is a worry for sure. If I were to split the cases, that would have to wait for winter.
And since I began this quest, two of my other bikes my brother has been riding have developed problems that need attending to, one of the weed eaters fell apart at the end, and yesterday, the mower deck on one the riding mowers broke a big bracket off at the weld. Did I mention we have 10 acres of now dried grass to keep down, and 100 almond trees to trim. A huge branch from a 200 year old tree fell on the tractor shed and it needs repair, and the list goes on.
I'm going to get one of my boats and the Seadoo ready for a warm weekend coming up and go play on the water, maybe I'll just stay on a beach all summer and eat crawdads.

 

[141987]

...I may find that's the least of my problems anyway. The errant tensioner piston is a worry for sure. If I were to split the cases, that would have to wait for winter.
And since I began this quest, two of my other bikes my brother has been riding have developed problems that need attending to, one of the weed eaters fell apart at the end, and yesterday, the mower deck on one the riding mowers broke a big bracket off at the weld. Did I mention we have 10 acres of now dried grass to keep down, and 100 almond trees to trim. A huge branch from a 200 year old tree fell on the tractor shed and it needs repair, and the list goes on....

I think you've inadvertently just written a great set of new lyrics to the Ray Charles' hit, Busted. https://www.youtube.com/watch?v=F3A6Z462SBs



Speaking of crawdads and almond trees, may I ask what part of the country you live in?

 

[edheiser]

Sunny California

I live in Oakley, Ca, right by the Antioch bridge in a house with sidewalks and street lights. Our other property is 6 miles out of Brentwood. It's been in my wife's family since the 1850's. We've been working on it for 9 years (when we both retired), and it's still far from what I would like.
I just got back from Fred's Welding, and the mower deck is fixed, more progress.

 

[edheiser]

Ach du lieber!

This bike is a puzzle of interlocking pieces. With the CHP crash bar frame in the way, it looks like the whole front end has to come apart to even look in the timing cover. Tell me I'm wrong!

 

[AntonLargiader]

You're probably right. The police bars on those R11xx models are a huge PITA when it comes time to remove a transmission or anything like that.

 

[dieselyoda]

"Ach du lieber!" is not the correct technological term for the crash bar issue. Farfrumgruving is the correct term

 

[rxcrider]

"Ach du lieber!" is not the correct technological term for the crash bar issue. Farfrumgruving is the correct term

and here I thought that was the term for self machining VW gearboxes

 

[edheiser]

Far what?

"Ach du lieber!" is not the correct technological term for the crash bar issue. Farfrumgruving is the correct term

It's far from groovy?..........ok that's a new one on me, translation?
This BMW it so fun to take apart, instead, I went out to the ranch and put a riding mower deck back on, installed a window AC, and demolished an old chicken coop. Easy stuff in comparison. I'll try again in the morning.