Knock, knock, knocking...

[chasestudio]

Looking forward to a life-affirming blast 'round the Hampshire countryside on one of the first spring-like days of the year I rolled my '03 1150R out of the garage and started it up.

I was greeted by a distinct 'knocking', apparently from the left hand cylinder (near-side in the UK). Not 'rattling', not 'ticking', but real 'knocking'.

It wasn't doing that when I switched it off last time, which was only last week!

So, I cast around the forum and found plenty of information about 'pinking' and camchain tensioners which was all very interesting, but does not seem to match my symptoms.

For a start, this ocurred 'out of the blue', with a cold engine. I haven't had the nerve to let the engine run too long. I adjusted the valve clearances about 500 miles ago, I re-checked them and they are OK.

So, I have a 19000 mile '03 1150R, with clean oil and super-unleaded gas that 'knocks' alarmingly. Has anybody heard of anything similar? Do boxer small-ends fail?

My perverse nature is (slightly) looking forward to tearing down the engine - please help save it!

Thanks, in anticipation.

[towerworker]

Chasestudio--

I had a similar occurence on an 03 that I had until this past November. At about 40K miles I started mine after it had been sitting a short while and it started with the most horrible knocking sound I have ever heard. From what you described it sounds just like mine did. Not a rattling but a real loud terrible engine knock. Scared the heck out of me.

Mine was on the right side cylinder and was extremely pronounced and loud.
I went thru the cam chain tensioner issue and made those adjustments but that did not help it. It finally stopped after running a few minutes and what I really think it was and CycleRob of this board also confirmed as well was that I had a small piece of carbon that probably built up on the piston and it broke off and made a racket until it was broken off and pushed out the exhaust port. Also right when mine started it seemed to crank extremely quickly as if there was little compression. That further suggested that the carbon had held a valve stuck open thereby not allowing compression to build up. Hence the fast spinning while starting.
I can't say for certain that you are experiencing the same but everyone I know include my service manager says that these engines are very nearly bullit-proof and it's extremely unlikely that there is a major engine problem.

Hope this helps

Wayne
04r

[CycleRob]

When it "occurred 'out of the blue', with a cold engine." and the knock is alarmingly loud . . . . It exactly describes a stuck open valve. The knock you hear will be loud enough that you'll be disturbed enough to reach for the ignition key to shut it off quickly. The sound you're hearing is the piston hitting the stuck open valve, overcoming the friction of the oil starved and scored -or- gummed up and jammed valve guide-to-valve stem sliding surfaces. Almost every time the piston impacts will end up bending the valve head enough that it will not seal properly, the idle will slow dramatically and likely stall. Cranking on the starter you will notice one dead cylinder's bent valve caused low compression in the characteristically uneven sound the starter makes. The valve, guide & seal will need to be replaced. Since you said " I adjusted the valve clearances about 500 miles ago, I re-checked them and they are OK" there is evidence they weren't damaged. I recommend you make the easy shots first and try to turn the engine crankshaft with a wrench to ensure there is solid, equal resistance of a compression stroke ONCE EVERY TURN of the crankshaft. If there is then it can be (very VERY rare) a spun or burned connecting rod bearing.

If the knock is not that loud it could be "the carbon chunk thing" holding a valve slightly off is seat, creating a large valve clearance tapping away until the carbon is blown out. The engine would run on one+1/2 cylinder until it does. It causes no permanent damage.

Here's hoping it was the second option.

.

[boxermania]

There is one thing that doesn't fit in the scheme of things;

I adjusted the valve clearances about 500 miles ago, I re-checked them and they are OK

If the check was done after the knocking and we assume the carbon bit lodged between the valve and the seat, the valve clearance would have been off, as in greater than spec. , likewise for the bent valve theory, as if the valve were to be bent, it would never seat correctly and that would have been notice, as mentioned above, on the valve clearance check.

It is possible that the carbon bit would have dislodged from the valve/seat and just bounce around in the combustion chamber.....quite honestly I have never seen "chunks" of carbon bouncing around....most of what I have seen have been fairly small irregular pieces 1/32" to 1/16" in diameter and about 1/64" to 1/32" in thickness. This pieces, will be blown out of the engine fairly quickly or will be smashed into pieces equally fast.

I would have to rule out a rod bearing, for two reasons, if it were due to lack of lubrication, both cylinders would have been affected and second the boxer engine is one sturdy piece of machinery, not particularly known for bearing failures.

So what is making the noise? I'm drawing a blank, but will stick my neck out.......could it be a loose valve seat? we have had some sporadic cracking on the heads in the area between the valves. A crack in that location could have loosened the seat......although that would have also shown up on the valve clearance check.

Personally, I would turn the engine by hand as CycleRob suggested looking for particular places where the engine might tighten.

Next I would remove the plug and do a leakdown test, that should get you closer to the problem, if there is one. Lastly, if there is a leak in the intake or exhaust track, by removing the TB at the head, or in the case of the exhaust track, the exhaust pipe, you should be able to see the back of the valve and the seat......

Good luck and please let us know what you find.......

[CycleRob]

Yes, such an engine knocking (failure) like this is very rare. I mentioned that the valve clearance recheck being OK would verify the valves were not bent, -but- the valves are so rugged that they could survive a few seconds of piston pounding with only a cold engine fast idle . Look thru the sparkplug hole for impacted carbon deposits at BDC with a bright light.

There are only a few things that can cause such a knock and they're all bad. Also, we are trying to do a remote diagnostic of a descriptive sound - - - not the best way to solve things. Is the engine otherwise running at the normal speed on BOTH cylinders??

There can be a rod bearing failure brought on by internal corrosion. A lot of cold weather riding and/or short trips can accumulate corrosive acids and turn a nice, shiny, slippery bearings into cloudy-fuzzy trouble spots.

Turning the engine by hand will tell an experienced mechanic a lot, especially minute rotational freeplay midway between TDC & BDC (rod bearing failure). A leakdown test is always better than a compression test because the location of it's telltale hissing tells you which component(s) are damaged. I have both testers, but most people and even some service departments do not.

.

[Arbreacames]

Chase,
Sounds to me like your one of your cam tensioners is stuck in the compacted position. The left one is easy to remove, so I would start with that one. The right one requires removal of the exhaust header, so it is more work. There's an other one in the front of the engine, but I suppose that one can wait until you have checked the other two first. Besides, your racket is coming from the left, so I would think that you are in luck.

[chasestudio]

Folks,

Thanks for taking the time to comment and advise.

I plucked up courage to run the motor a little more - as the engine warmed-up the knocking diminished and finally disappeared.

I suspect a drained camchain tensioner was to blame - not something I have experienced these last two years. A very disturbing symptom - I think I may be looking at the R1200 upgrade.

Regards, Ian.

[Beemer1150]

Sorry, late in adding to this post.

I had the same a while back on an '03 R1150R, with about 16,000 miles showing then. LH pot too.

Used the bike regularly for commuting for about two years. Moved abroad last summer and left it laid up for about two months. Collected it in September and did fairly quick (80mph-cruise) 500-mile delivery trip without problems (except blown clutch slave - see separate posts!)

Ran for about 200 miles over two weeks in late September at fairly high speeds (80mph average with 100mph-plus spurts and very high ambient temperatures (30 degrees C plus) and then laid up again for about 4 weeks.

Started up in late-October and rode off for 20 yards (metres here!) to have exactly the same knocking - frighteningly loud, heavy, low frequency knock. Really bad! Switched off expecting terminal damage and pushed home. Decided to re-start to isolate problem - no knocking and running as sweet as a nut!

Well over 1,000 miles down the line there has been no repeat, and I'm guessing one of the temporary problems outlined by our more knowledgeable members was to blame.

Perhaps best not to worry too much...