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Discussion Starter #1
I went to look at a K1200lt this morning. It's a '99 bike with 42,000 miles on it. When the guy started it, there was quite a loud "knocking" from the engine somewhere. I've not heard anything so loud in either of my other two LT's I've owned. The guy said it had always done it and it went away when it warmed up. Is it likely to be something that I should walk away from?
Thanks

Simon
 

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I'd walk away, they shouldn't knock like that. My "02" developed a knock like that the first year I owned it and it didn't go away when it warmed up. Ended up replacing the motor. The dealer never did figure out what it was, they shipped motor back to Germany and they don't tell you what they find.

I'd just walk away and find another bike, why take a chance. Just my .02
 

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Most likely it is the gear set between the crank/clutch/alternator. These are fit on initial assembly from a choice of clearances in straight cut gears. Some rattle more than others. My 05 is particularly noisy compared to other K bikes. If you hear it at idle and it changes with increased rpm or load then that is what you are hearing. Nothing to worry about.
 

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I sure do not know what the noise is, but my 99 with 50,000 miles is so quiet at startup and thereafter that I can still hear the little voices in my head.
 

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K bike rattle

jzeiler said:
Most likely it is the gear set between the crank/clutch/alternator. These are fit on initial assembly from a choice of clearances in straight cut gears. Some rattle more than others. My 05 is particularly noisy compared to other K bikes. If you hear it at idle and it changes with increased rpm or load then that is what you are hearing. Nothing to worry about.
Lots of discussion on this subject in past threads. My 2000 is noisier than most and it concerned me at first. I did lots of investigation and came to the conclusion that jzeiler reports here. Helical gears between the crankshaft and countershaft puts a longitudinal force on these shafts which can then oscillate when the driveline is not loaded. There is a specification for endplay in these shafts and if they are on the loose side you get the rattle.

Some have attributed this to the alternator because when you turn on the lights or other electrical load the rattle quiets or goes away. If you load the driveline with the bike at idle by holding the brake and slipping the clutch and the rattle disappears then the source is this classic K-bike driveline rattle.

My bike now has about 60K miles on it. It still rattles at idle. Maybe less than it used to, or maybe I just don't notice it anymore.

If the rattle behaves as I described above, I would not let it deter me from buying the bike. Some do rattle more than others and it is not a problem.
 

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Simon it just does not sound right, no pun intended.
I would keep on looking.
 

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My '99 was really noisy at when I bought her - the owner said it was normal, I only half believed him - the engine still runs fine, years down the line.
 

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Discussion Starter #8
OK chaps, thanks. IF it is the crank/gearset is it a major teardown jobbie to replace the bits?
 

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Fixing the bottom end K-bike rattle

simon said:
OK chaps, thanks. IF it is the crank/gearset is it a major teardown jobbie to replace the bits?
If the rattle is indeed bottom end K-bike rattle, you don't need or want to fix it.
If I were considering purchasing a bike that had this characteristic I'd do the following:
Have a trusted, competent mechanic do a compression, and leak down test, and check everything functions normally.

Do the test I described in a post above in this thread, i.e. hold the brakes, slip the clutch and see if the rattle quiets or goes away. If it does, it is consistent with the K-bike rattle and does not need to be fixed.

Listen around the motor with a mechanic's stethoscope (or a long screwdriver held against the ear). If the sound is loudest from the bottom right side of the engine case then it is consistent with K-bike rattle.

If the bike checks out and you are willing to live with the rattle, buy the bike. If you don't like the rattle, pass on the bike. Finding a different bike will be lots easier then doing the engine teardown and checking the shims that limit axial movent of the crank and counter shafts. And even if you did all that, there's no guarantee that after you put it all back together the rattle will be gone.

Some of these K motors do rattle more than others and it is normal. They are noisy at tickover rpms, like rocks in a can.
 

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Check to see if the noise goes when you pull the clutch in. If it does, it isn't an engine problem. These engines are generally bullet proof. I would suspect clutch/gearbox issue.
Waz
 

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I just bought a 2000 LTC, 25K miles, with a rattle like CharlieVT's. At first, it freaked me out. Mine does not go away as the engine warms, and rattles when I decelerate and if it's not in gear revving the motor. I've gone about 2K miles now, no change better or worse. Only time will tell, for me.

The previous owner had it into the local BMW shop a couple times, thinking it was the tupperware rattling, they didn't think it was a problem, just some are noisy.

My bike was pretty much mint otherwise, and the $7500 price was cheaper than any other local LT's I have seen for sale. So I am glad I bought the bike (at least so far since it's not getting worse).

My advice - use it to get a good deal on the bike. If you're not getting a great deal, find another one. LT resale appears to be pretty lousy and there's a lot of them around.

Wayne
 

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Well, I agree with what almost everyone else has said about the LT rattle - my 2000 with 102,000 on it only has the tiny rattle and it's not noticeable most of the time, but of course I did notice it when I test rode mine and I've heard it with other LT's ... I agree that this type of noise is something that should be looked at like it's not a problem and not something that needs to be fixed



But from your description of the noise, this isn't a rattle at all, but a "loud knock from the engine" - this doesn't sound normal at all and definitely not like the standard noises that most all LT's make - I would look into this a lot more carefully - the advice about having a mechanic check it over with a lot of scrutiny was the best advice I've heard on this one



One thing to remember here is the cost of replacing the engine if it does go down the meat hole in the next year or few ... while some repairs and maintenance on the LT is reasonable and even cheap, there are a lot of things that make the difference between the bike being repaired and it being a parts bike for others to use ... are you willing to put that much into this bike and still be happy with your purchase?



Another thing to think about ... even if it's not a 'standard' LT noise but you decide that you're comfortable with it anyways ... even say that it lasts another 5 years with this same noise but runs perfect the whole time ... you are still going to have a really hard time selling it with this noise because any potential buyer will be asking the same questions that you are here – if you buy this one, you may end up being stuck with it until it's either time for a complete overhaul at your expense or it's time for it to join the beemer bone yard at your loss - if you buy one without this funky noise at least you will be able to return it to the used market when/if you decide to buy another one



My LT does make a little clatter noise when it's under load, but it seems to go away when it's warmed up and I've not ever heard it when it's idling so I think mine is normal - what you are describing would bother me a lot



There's all kinds of evidence for these engines lasting 100,000+ miles when they are taken care of, so I wouldn't say that this knocking is something you should just deal with - as mentioned before, there are plenty of LT's for sale on the used market and the prices are great for what you get - there's no reason to sell yourself short with a hairy engine noise unless you're getting such an amazing deal on the bike that you would still come out ahead on the deal if you had to replace the engine ... just my 2c



Best of luck, let us know what you end up finding out about this - I'd really like to know where this knocking is coming from if you ever find out

 

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Discussion Starter #13
Thanks for all your advice gents. I decided to pass on the bike. I'm sure it'll run for miles and miles with the sound, but it'd just worry me too much every time I started it up.

Simon
 

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Good choice!
 

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I think you made the right choice, but...

my 2000 LT with 102000 miles has just started a deep knocking sound at idle, coming from the lower right side of the engine, and a 'tinkling' sound as I am starting out from a stop, or slowing down using just the engine (ie: engine braking, kind of). The knocking goes away when I accelerate, but I can still hear some tinkling going on down there as I work my way through the gears. To me, it's sounding like time to replace the clutch again, but then again, the bike is running fine, no clutch slipping, same mileage, nothing has changed except the addition of these noises. The tinkling occurs during mellow launches from a stop light and during stressful take offs too, no difference on how I drive seems to change the tinkling sound.
What confuses me is: This was not a normal sound for this bike, but it is running fine. Am I just waiting for disaster? It's my daily driver, so I am willing to put some money into it of course, but is this something more than just a clutch job?
Not that a clutch job is 'just', but hey, 77000 miles on a clutch is a lot to be asked, right?
 

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secretaryrick said:
I think you made the right choice, but...

my 2000 LT with 102000 miles has just started a deep knocking sound at idle, coming from the lower right side of the engine, and a 'tinkling' sound as I am starting out from a stop, or slowing down using just the engine (ie: engine braking, kind of). The knocking goes away when I accelerate, but I can still hear some tinkling going on down there as I work my way through the gears. To me, it's sounding like time to replace the clutch again, but then again, the bike is running fine, no clutch slipping, same mileage, nothing has changed except the addition of these noises. The tinkling occurs during mellow launches from a stop light and during stressful take offs too, no difference on how I drive seems to change the tinkling sound.
What confuses me is: This was not a normal sound for this bike, but it is running fine. Am I just waiting for disaster? It's my daily driver, so I am willing to put some money into it of course, but is this something more than just a clutch job?
Not that a clutch job is 'just', but hey, 77000 miles on a clutch is a lot to be asked, right?
I've owned a LT 05 from a while now. Suddenly, this knocking started and I also have the tinkling exactly on the same conditions you describe. As I read your post, it was like reading my bike behavior. Since this know/tinkle combo is something new for me, you might imagine I'm so worried about it! How did this case come out for you? Any reference would be more than great.
 

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You do realize that you responded to a four and a half year old thread, right?
 

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My '99 LT with 94,000 miles at times sounds like someone threw a box of rocks in the crankcase. At idle and low rpms the engine clatter and tupperware buzz is a bit disconcerting. This is not my first K bike and is just the nature of the beast IMO. Like the top heavy feel at slow speeds....it vanishes when you pick up a little speed. Look at it like this...if our bikes had the exhaust noise of a Harley, we wouldn't hear a little engine clatter :histerica
 

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I do know I'm posting on something truly old... but this just happened to me and if more time, more experience with the issue, right? :cool:
 
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