Engine knocking

[CycleRob]

I was actually toying with the idea of taking a long ride to Wayne's house for an in person diagnostic with my chrome & black hose mechanic's stethoscope (all true). Riding from Gainesville, GA to Staunton, VA I made a WAG figuring it might be a do-able 4 hours or so, -but- by MapQuest's calculations is actually 7Hr:50Min and 480 miles (772.5km) away. That's a l-i-t-t-l-e too far for a one way friendly house call and lunch with Wayne&Rosa.

About the noise. Why are things like this happening to a high quality, German engineered masterpiece?
Thinking it over, I keyed in on the vitals:
1- Happened all at once.
2- Sounds alarmingly loud.
3- Sound varies with engine speed above idle.
4- Engine spun faster on the starter like there was no compression.

All that points to a valve problem. A sticking intake valve covers all those symptoms perfectly, yet I would not bet too much money on it.

What I heard on the phone sounded really serious and you gotta know those kind of noises do not get better by themselves. Tensioner assemblies do not go really bad all-at-once unless the spring breaks or it's piston gums up and seizes. His did not. Looking inside under the valve cover, he said nothing appears out of the ordinary.

My advice to Wayne considers seriously expensive damage that can occur if the bike was ridden instead of trucked the 2 hours to the wizards at the BMW dealer. Even worse if he only makes it half way. Because there are only a few moving parts in the engine that can make the thrashing noises like I heard, there are just a few possibilities. One of the six chain guides is cracked, dislodged or broken, a failed auxiliary shaft tensioner or spring, It can even be a pressure plate failure, or a transmission or throwout bearing gone bad. This situation has me flustered. We should get the answer by this time next week. Hopefully, it IS the camchain ten$ioner and they have one in stock.

[towerworker]

The knock is all gone!

Just for giggles and grins I removed the tensioner again. I visited my local Lowes and found a small package of stainless #8 flat washers. 5 in the pack. The washers make a perfect fit in the piston on top of the spring. btw--I had previously stretched the spring approx 3/16". When removed it was back to it's original length prior to stretching. With washers installed and all put back together the bike started and ran smoothly with no knocking or other unusual noises. Took it for a short ride which stretched out to a substantial ride as my confidence grew. The engine is back to sounding like an old Singer sewing machine (as my coworkers call it). Ran quiet and smooth. Big relief!!!

I just got off the phone with Cyclerob and we both agree it probably started with some carbon flaking off the piston or cylinder head and getting stuck between a valve and valve seat. The hammering probably had a secondary effect on the tensioner so I had multiple issues instead of just one. Bottom line is everything now appears cool!!

I want to thank all those who offered suggestions and help with my bike---especially ProductUser (Tony) and Cyclerob. You guys are great and we're all fortunate to have you as a valuable resource!!

Wayne Bowyer

[Byrdguy]

I believe I'd replace the defective tensioner.

[NoRRmad]

Isn't there a newly-designed one that replaces the original?

[CycleRob]

The newer replacement one is (I believe) only for the left side (?)

Glad this problem was resolved and all for about a $2 bag of 5 SS #8 washers and time to remove the headers and tensioner.

I believe we can blame BMW for poorly designed camchain tensioners with weaknesses that only show up when the odometer reading gets bigger. Adding SeaFoam to the fuel to remove carbon deposits like both Wayne & I have done now seems to have unintended consequences IF you are unlucky enough to have a small gooey flake fall onto an open valve seat then get packed into place. That fast spin on the starter where only the left cylinder was pumping compression while the right cylinder intake or exhaust valve was closing on a carbon chunk started the problem. With the resulting huge valve clearance the running engine's valve banging opening/closing shocks were transmitted by the camlobe to the chain slack and therefore to the tensioner. Man, would I have loved a glass engine window and a bright light to watch that chain guide's wild movement whose loud noise upset Wayne enough to turn the engine off. Looks like the tensioner spring can't take the large amplitude rapid cycle abuse and it sacked to a shorter length and weaker force. Now there's all-of-a-sudden a very noisy engine and a very worried owner.

On the phone, Wayne was grateful for what he learned from most members on this board. Others that have found cures to quiet a noisy stock camchain tensioner with different springs or washers played a major role for Wayne in saving a lot of money and 4 hrs wasted driving time. The mods were inexpensive and do-able. Kudos to the ambition, determination, wrenching ability and analytical thinking of our friend Wayne (TowerWorker) to use that info for one last try. Removing both headers each time the right side tensioner is removed is no picnic and it's a good thing it did not deter Wayne from doing it one more time before the car trip to Lowe's for some SS washers.

I'm think'n every one of thousands of mild clatter startups -plus- normal chain and guidebar wear conspires to shorten the lifespan of the 2 poorly designed camchain tensioners. Who'd-a-thunk a $2 bag of washers can (permanently?) fix a scary-loud thrashing OilHead motor?

I feel much better now.

[towerworker]

Plan to order replacement springs for both tensioners this week. Rob seemed to thing the washers are a good fix but best to replace with the right stuff.

Wayne

[Boxer]

I just went and scanned the MAX BMW parts fiche for this tensioner spring. Very interesting! They don't even show the NEW tensioner setup for the left side. They list the spring as the same part for left and right but the piston, gasket ring and tensioner are different for each side. There are two tensioners actually listed for the left but one says NA.

The spring costs $1.50.

[ProductUser]

Wayne --

I'm glad everyting worked out for the best!

Tony

[DSKYZD]

Awesome! Good job all-around from advisers to advisee.

Makes me want to change out my camchain tensioners.

[sweatmark]

Excellent information, glad you're back up & running, TowerWorker.

Looks like the camchain tensioner maintenance/upgrade is mandatory for our long-term R1150R ownership... BOTH sides' tensioners.

Thanks to all for sharing the info.

[towerworker]

I just have to say my bike is running so smooth and soooo quiet!

Just the little light tic, tic, tic from the valves at idle. Reminds me of Mom's old Singer when I was a kid.

I wonder if I could buy a case of the #8 stainless washers from Lowes, package and label them as a Tensioner Upgrade Kit and sell them to BMW? You reckon?

Productuser gave me the idea and Rob said it too. Maybe we could all become wealthy over a 99 cent bag of washers!

Wayne

[geothepencil]

Perhaps as wealthy as the folk who package a whole bunch of big o-rings to install on your grips for insulation/size increase/whatever. Not a bad idea but at a pretty good mark up based on what I have seen in the industrial catalogs. And yup, they work pretty well !

Of course they don't work on all BMWs, Just the ones with the skinny hard grips.

geo

[ProductUser]

Just to add some clarification:

The upgrade to the left tensioner is actually the cam chain tensioner on the R1200 series (hexhead); there is no upgrade for the right hand tensioner.

Chicago BMW has the left tensioner upgrade in kits.

Although adding washers to the right side tensioner has worked, there is very little long term data to support this as a perm fix (I sound like a drug pusher). However, the person that initially performed this fix has ridden several thousand miles with the washers in the ride side tensioner.

ProductUser

[towerworker]

I hope all realize I'm not serious. Just tickled that I'm not faced with a seriously sick motor.

My intentions are to replace the modified spring with a new one. My dealer is closed today---will contact tomorrow. If I felt really good about the longevity of the washers I probably would leave them alone but since there is apparently no real long term history I think it safer to plan on a more proper fix.

Wayne

[CycleRob]

Was going to make a new post, but it's more relevant here.

I decided to remove both tensioners, add spacers and see what sound improvement would occur. My bike had those RPM sensitive CamChain rattling noises. They seem to have gradually gotten worse and I got used to them. After reading and writing about this OilHead character flaw and having accomplished only making a 4 cup bowl of Jello and spraying weeds today, I decided it needed a "take-apart" NOW.

Glanced at my watch and it's 3:31PM. I looked at all the bike's relevant parts and made a mental list of what I'll need. Flash memory saved. All mechanics do this. Get the tools 3 steps away. 12mm, 15mm & 17mm 3/8ths drive sockets, breaker bar, stubby fine click ratchet, 2.5" wobble and 1" wobble 3/8ths drive extensions, magnet (on the end of a SEARS screwstarter tool), 20" boxfan, 6" steel ruler, small oil squirt bottle, 2 small rags and can of Gumout carbclean spray. Plug the blowgun into the air compressor's airline and turn on the 1/4 turn valve.

Plug in and aim the fan at me . . . . . it's 97F (36.1C) in the large shaded open area just outside of my garage. Look at my watch. Remove the 4 header nuts with 12mm socket and loosen the 2 catbox header clamps with 15mm socket. Left the crossover clamp tight so it holds alignment. One hand pushing on the front of the motor so I don't pull it off the CenterStand(!!), with the other I grab crossover pipe and give it a sharp YANK straight forward, expecting stiff resistance. Wrong, I almost smacked the front wheel with it and fell over backwards. It SHOT off like nothing! Cool. One yank and it's in my hand. Look at my watch. Start to finish for exhaust header removal: less than 2 minutes !!! FYI: It was off once over 2 years ago so that made it easier (?).

Rush to remove the harder one first, the left side. Re-aim the running fan. Ahhhh. Nice. Put the 17mm socket on the tensioner bolthead. Insert the longer wobble extension into the shorter one and plug that assembly into the socket on the motor. Plug in the breaker bar and give it a loosening yank. Remove the tools then turn the bolt head with my fingers. All 3 parts come out easy, one-at-a-time, the last one with the magnet. Measure the spring free length@69mm. Last nite I filtered thru the CD shop manual looking for a spring free length in the specifications sections but found absolutely nothing.

Scrounge thru my toolbox's junk drawer for suitable spacers. Find a very short 6mm allen head bolt whose few threads fit inside the spring and the 6mm tall head fits inside the piston. There's no oil hole in the left side tensioner's piston head so the bolt head is OK down in the hole. Adding 6mm (less than 10%) to the very long springs compression length will definitely compensate for severe service spring sack, plus normal CamChain and ChainGuide wear, which a new spring would only fix for a while. OK. Spray clean the parts, blow them off, lightly oil sliding surfaces and re-install the tensioner. The bottom oil bleed hole prevents filling it with oil. Go inside the house to wash my oily hands and take a wiz. After that, I re-aim the fan & go to the other (right) side.

This one's gonna be easy. Breaker bar and 17mm socket loosen it pronto. It turns so easy I unscrew it by hand with rags below to catch the small amount of oil. Remove and measure spring free length@68mm. Scrounge thru junk drawer again looking for a hollow bushing type spacer the right sizes. Find a tiny but rugged, aluminum bushing slightly larger than the spring diameter that is long enough when a small fat washer is added to it, against the spring. Total length 6.5mm. Longer than the 6mm spacer on the other side because this spring sacked 0.5mm more. Again, spray clean the parts, blow them off, lightly oil sliding surfaces and re-install the tensioner. Go wash my oily hands again inside the very cool house.

Now comes the part that briefly raised my blood pressure about 5 points. Re-installing the headers. I had to lay on the cement to see all the 4 install points simultaneously. Starting the pipes into the CatBox first, then onto the top bolt flanges. Wiggle-push-wiggle-push and it's on. Install the 4 nuts and repeat pattern tighten them while smacking rearward the crossover pipe with my palm to make sure it's home. DeadBlow loose shot plastic mallets work but they sometimes use too much sharp force without tactile feedback. I did not want to maybe damage the exhaust port stud's threads with too much force. After hitting it with my right palm several times, I wish I'd got up and walked the 3 steps to get the F'n Mallot. Once the header nuts are tight I tighten the 2 CatBox clamps. Done!

Pick up the tools and put them away. Go wash my hands again inside the house and get the bike's key. Look at my watch and it's 3:57PM. Yeah. Twenty-Six minutes. Top BMW techs would rate that below par, but HEY! I'm retired.

Start the bike fully expecting empty tensioner reservoirs clattering like hell until they fill. It starts without any clatter and runs so quiet . . . . just like when it was new. ZERO rpm sensitive CamChain rattle noise !!!!!

It's 7:15PM now. It took me well over 5X as long to type, read, preview, edit, (many times) and post this write-up than it took to actually do the work. I love this bike!

[towerworker]

That is so cool!!

wayne

[Byrdguy]

CycleRob, how many miles are on your bike? Mine (an 02) has about 14K and the left tensioner had been bad for what seemed like forever before I replaced it (discovered thanks to this forum), but I still have intermittent rattling similar to what you describe above. I guess your described fix above is definitely worth a try.
Not this weekend, BTW, I'll be in your neck of the woods in Suches. Can't wait, a well needed couple of days in riding Heaven.

[Sunbeemer]

Nice job and a great write-up! Thank you for the effort.

Something I worry a little about is the long term effect of having a shored-up spring working in the cam chain tensioner. When I "upgraded" my left side tensioner, I recognized it applies an increased amount of pressure against the guide, which is what keeps the chain from rattling - a good thing - but will also keep more tension on the chain when it deflects from its "normal" running position, just like those shored-up springs will. Since the elasticity of the spring has been increased overall, it's putting more pressure on the guide which is, in-turn, putting more stress on the chain... so my $78.82 concern is... will this accelerate wear on the guide(s), chain(s) and sprockets over the long haul?

Still, it does sound a lot better now! But, will we be paying for it (by having to R&R the cam-chain guides, etc) down the road?

[CycleRob]

When the engine is running the chain hydroplanes on a film of oil and the parts never touch. It is the same for the bike's pistons and the cylinder walls. They do not make contact when the engine is running. Without the oil film, the fast moving, hard pressing, steel CamChain would burn thru the hard plastic ChainGuide in a few minutes. The tensioner's spring pressure is only part of the total force the tensioner applies. The oil pressure inside the piston pushes even harder. The R1200R left tensioner replacement likely has a larger diameter piston and smarter oil pressure utilization to better tame the wildly cycling CamChain.

The installed spring pressure is so lightweight that a lot of ordinary things can serve well in the ShadeTree Mechanic's preload recovery upgrade. Adding a little less than 10% of free length in additional preload seemed safe enough to not damage any parts -and- it is large enough to both recover preload pressure lost by normal wear and affect a real performance change. Prior to reinstalling the tensioner I hand compressed the piston all the way to flush with the end of it's surrounding Aluminum housing, then removed the spring and remeasured the free length again. It was unchanged. Great. My 6mm additional preload does NOT do any damage even in the most extreme operation scenario.

Worried about the extra ChainGuide pressure? You should really be worried about the hundreds of hours the noisy, thrashing/rattling CamChain rapidly beats everything around it, and itself, to death.

[Arbee]

I heard a similar terrible story from a guy who bought this cheap bike
because of the engine knock and it turned out to be the cam chain setup.

BUMP... Waiting... Waiting...