Hello ,

I can hear a metalic rattle while coasting ( no rattle in neutral coasting, only when in gear I can hear the rattle - any gear , any speed , engine braking ) . Seems to come from gearbox. Oil was changed recently , no metalic debris on the magnet drain plug. The rattle is irregular and if I accelerate slightly it goes off. No clutch slip or jumping from gears, changes ok without effort.

Any thoughts on this?

'99 1200LT , 90k km.

Thank you .

You might want to check to see if your rear brake rotor is loose due to wear at the floating pins. Common problem that usually only results in a clang (cow bell) over bumps but can get bad enough that you hear it pretty often. If not that, check the heat shield on the muffler to see if one of the mounting points is loose causing a rattle.

Already ruled out both the heatshield and the brake disk ... The rattle sounds like tapping with fingers a very large frying pan . Can't find a better description ...

run it in gear on the centre stand try and replicate it, use 2 person to observe hope you find it and its not serious,

Just the off chance did you get a new helmet? Are you hearing something that was always there but not noticeable?

The only difference between in-gear and neutral with the bike moving and the engine running is the loading on the input shaft which does have a spring cushion.

Actually I do have a new helmet but is quieter than the previous one. I will try to find the source of the rattle with the bike in gear on the center stand. Tks.

If you still have the old helmet go for a ride and see if you still hear it. I always hear new things when I get a new helmet. It is even worse if you ride it a shot distance (dive way) with out a helmet at all. Scary sounds.

Well, with or without helmet , old or new , the rattle is there. And I found that when the bike sits on the center stand, especially when the engine is cold the rattle appears also. Only in light open throttle and neutral. But not as loud as it sounds in coasting. Still can't pinpoint the source.

there will be a rattle at idle that is normal usually goes away about 1200rpm. there are straight cut gears in play, (alternator) should be worse if you load it up. but you definitely shouldn't hear it once you are rolling, find someone close to you with an LT and have them take a look see

maybe check your exhaust support bracket for tightness. (The one you have to remove when doing transmission fluid chg)

Bob

I'm no tech guru liek John Z is but my LT had that cowbell rattle and did get rid of the noise when I changed out the roter and new pads with EBC's.

Have someone hold onto your rear brake disk while sitting at idle (in neutral obviously) and see if that makes a difference.

Ruled out the rear brake disk and exhaust bracket . Brake pads are new ( 600 km on them ) . Cowbell brake disk sound is very different from the rattle I hear. Unfortunately there is no other LT in the area in order to compare the sounds those bikes make....

Can you record and post it or isn't it that pronounced.

I will try to record the rattle ( engine cold & centerstand ) . The louder rattle is when coasting but that is almost impossible to record due to engine / road / wind noise. Tomorrow I give it a try & post the result.

John Z is so good at forum diagnosis that he once told a guy that one of his #2 cylinder exhaust valve seals needed replacing just from the sound of the motor, man JZ is good.

The obvious question which I don't think has been asked or answered, is:
When did the sound begin as related to post-maintenance? Or maybe after a particular ride? Was it just out of the blue one day when you fired it up?

In trying to rule out the simple things before speculating on deeper mechanical maladies, have you taken a flashlight & done a good look in the luggage for a stray item like for instance, a small tool that's loose in the bottom of a side case or trapped somewhere? Stranger things have happened.

Failing any of that, I like the idea of a friend helping while you do the braille method - tracking it down by feel.
Good luck.
Bob

Here http://youtu.be/gPDcsqqUiXY
is the audio file and you can hear the rattle. It starts at sec 20 , louder at sec. 37, then at sec 42 a move to the right side of the bike. It is recorded with my phone - not the best audio quality....

The bike is fully serviced. Audio file was recorded with the bike on center stand, cold engine , neutral, max . 2000 rpm.

I noticed the rattle after moving this spring to another town. The roads I used till last year were not very good with patched tarmac so there was alot of noise from the road condition.

There is an intermittent clanking sound, would not call it a rattle, have you tried long screwdriver ear pressed to handle end tip applied to parts of motor and transmission to see where loudest.
Also can use a piece of hose to ear other end to different locations to try and narrow location of sound
Very interesting

I keep thinking that the sound is something is loose in the exhaust but I would think you would have found that by now. If it is on the center stand and not in gear, I don't see how it could come from the transmission.

It's internal not external. All bolts I found were tightened, nothing's loose .... The fairings were dismantled and I checked all that's external and attached. I'm out of ideas , waiting for a major failure....
Did not heard yet of K engine parts coming loose.
BMW V8 and V12 ( 90-98 ) engines had oil pump bolts coming loose , rattle and pump losing oil pressure , oil spray bar banjo bolts also coming loose and ruin camshafts due to lack of lubrication. So I am not unfamiliar with horror storyes caused by poor design . Still, I did not found symptoms like I described. I will search for a mechanic's stethoscope and isolate the area ...

Something is loose inside engine HOWEVER it does NOT sound like recurring with RPM cycles like a connecting-rod or main bearing would do. It is intermittent like a bolt running loose inside the dry clutch housing creating a hollow sound (clutch housing is like a big semi-empty metal can).

Could you do the same test (center stand in neutral) and for a while (maybe 1 minute) hold the clutch-lever pulled (even if you are in neutral). Try to see if funny sound goes away or change while clutch lever is pulled.

At idle, the K1200 engine will always sound better when clutch lever is pulled because of design of main+secondary shafts inside. In your case, this new sound might be related to either clutch or one of these secondary gear/shafts (many parts related to these shafts/gears including alternator rubber damper).

My Harley has a similar sound that I couldn't track down... Until one day by accident I caught a rag on the heat shield, it popped and I heard the same sound. One of the spot welds had come loose but the strange thing is that no amount of touching, looking, tapping, wearing of tinfoil hats, saying voodoo chants, etc. had uncovered the sound. Took all the heat shields fully off and the rattle was gone.

Good luck and my you find something soon for piece of mind.

How could you even hear a sound like that on a Harley?

Sounds very similar (but not as loud) to my 99 LT with 50K miles. I sought help from the forum and, like you, received many great suggestions as to the source. After expending about a hundred hours and innumerable nights in the garage diving into the bike I finally found my noise to be (I reason) backlash and play in the alternator lash up. I can power up the alternator with a test load of 50A and the "rattle" goes away as the alternator grunts and takes up the slack. At normal idle and just above my noise is a somewhat random "banging" that drives me crazy at RPM below about 2K. It worse when the engine warms up. It grew progressively louder until it settled in decibel-wise at about 50K miles. It's not getting any louder so I just live with it. I've now observed my same noise in two other local RTs of about the same era. In fact, most of the LTs I've listen to sound like a box of rocks at idle and at slow speeds. It's typical of my LT. I love it, No I hate it. No, today I love it.

Good luck. I'll be following the post to see what you find.

now that i have heard the noise it doesn't sound right to me, that is not a normal rattle, first thing i would do is remove the tappet cover and check chain, guides, and tensioner

The test revealed nothing . Rattle still there...

Dismantling the bike right now is not an option , I don't have the time. I will use the car and maybe next weekend I'll start investigating . Thank you all for ideas.

Voyager Grasshopper, Even the blind one can know the grasshopper is there if they pay attention. ha ha.
Potato, potato, potato is different than Potato, rattle, potato, rattle.
For sure each bike has their sounds and their noises.

I had this issue with the bracket - one of the two welded wires broke off, making rattling noises. Welding it helped for a while, but it broke again and is still rattling.

BJ

That is a very wierd rattle. Good luck, that kind of problem is so damn frustrating, I feel for you.

Try unbolting the left side footrest which is what holds the approx 3 ft long exhaust heat shield and look for any issues with the clamping of the heat shield. Check for any foreign object trapped under the heatshield. Also with the heat shield loose, see if the sound attenuates while holding heat shield with your hand to dampen it's vibration.
(Sorry, I just noticed you had ruled out the heat shield)


Bob
ps: This is a long shot, but do you have any toddlers that play near the bike? Kids with drop things into crevices. I once pulled a bunch of pennys out of a car stereo of a used car I had just bought.
Got kids?

That almost sounds like the CAT substrate has broken free in the exhaust. Could pin point it with a make shift stethoscope.

A mechanic's stethoscope is a remarkably helpful tool. I'd listen around with one before I started taking things apart.

Useless, inane thread highjack:
I was going to suggest maybe someone put rocks in one of his hubcaps.
Now who remembers that gag? (If you do, you're gonna date yourself.)

It's an old technique but holding a screw driver handle ( plastic ) against your ear and touching the blade to various locations can work surprisingly well.
May be able to isolate the sound to a localized area.

Purchased a mechanic's stethoscope . I will post my findings....

A lil' update ...

Well, I'm back from my summer holiday and I had some time to investigate the metalic rattle. I've made around 3000 km since my last posting here, the rattle sounds the same - not worse. I used the stethoscope and it seems that the sound comes from catalyst area, not the engine . I think something is broken inside. Actually that makes sense to me now since I had a 5 cm long crack between the catalyst and muffler which was welded early this year. Maybe it is related. Anyhow , I'll live with it as I cannot find another explanation for now.

Also checked the fuel pressure, because the bike is running rich . The pressure is 3.9 bar instead 3.5 so a new pressure regulator will be fitted this winter .

Has anyone tryed the pulstar spark plugs ? Are they worth it? Found
Pulstar HE1HT9 Plug @ $17.50 each ....


Best regards,

First though after listening the video: Something is loose in(side) the exhaust pipe.

I get a metallic rattle all the time, but that's just from the CDs I listen to.