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LC4 640 Adventure engine noise/vibration/rattle

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Newbie

acleave

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Hi,

I just bought a 2003 LC4 640 Aventure and love the bike, but the engine seems to be making a hell of a racket. I get this rattling/knocking noise from the left side when the clutch is out but it quiets down when I pull it in. The engine vibration seems excessive as well and I get a nasty buzz coming up from the pegs at around 4k rpm. We opened up the clutch cover and checked around, and everything seemed fine ie. no loose balance shaft bolts or worn bearings ( the more common problems from what I have read ) .

I read on a bunch of forums that this bike has a lot of vibration but I am a bit worried about the noise and shake and wanted to check if anybody else had the same experience and knows of any fixes. I also compared the engine to that of an LC4 Endure 2003 and that engine (which is supposed to be the exact same engine) was a hell of a lot smoother. The mechanic says it's not normal but says he can't do anymore without splitting the whole engine and having a poke round.

So, anyone have any ideas?

Thanks,

Adrian

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orange chicken

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Vibration and noise perception is a very individual thing, but what you're describing sounds normal to me. There are two things that are important steps to reducing the vibes. One is to get it jetted properly. Go to KTMTalk.com and/or AdvRider.com and do some searches or ask the question there, and they'll give you all the tech info you need. I'm a jetting idiot, other than recognizing how much better my bike ran and how much smoother it was after zeroing in the jetting.

What's the other thing? A few miles to get it run in. How many miles are on it? I think it took mine until about 1500 miles before it smoothed out. It's still a much more "lively" feeling motor than a KLR650 or BMW650GS, but you got an adventure/dual sport bike that doesn't make a lot of compromises. Get lots of seat time and you'll grow to love it like you never thought possible of any machine.

If that mechanic doesn't have lots of experience with the LC4 motor, then I would ignore his advice and find someone else. They are tough powerplants, but they have their idiosyncracies, including making some noises that sound "non-musical" to the uninitiated.

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Newbie

acleave

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Thanks for the help. I've got the bike second hand with about 6500 km on it. I don't really mind the vibes or the noise but I got freaked when the mechanic started showing me LC4 Enduros that didn't make the noise. From what I've read I do believe it's normal and am going to give it awhile and see.

On another note, do you know if the Airbox mod (using the KTM hard part hiflow airbox cover with screen) and a bigger jet makes a significant difference to power?

Thanks,

Adrian

ps. I think I'm just a bit overprotective because the bike is new... ? I am pretty sure it's a real workhorse.

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Rookie

KTMITALIA

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I had lots of rattle too before the service (on idle and mostly after the first cold start in the morning) but now, after the service is gone. My mechanic told me that the noise was caused by the valves. Just needed to be adjusted properly . By the way , i have a 98 Adventure with 20.000 km on it (motor only 12.000).

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