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07-09-2012, 01:49 PM
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#1 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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Updating another thread:
Does this sound like a proper airhead? http://dl.dropbox.com/u/90599092/bmw%20sound.mp3 After I rebuilt both cylinders, I noticed this sound. With my cell phone in my mouth, tucked behind my windshield, I got a clip of what I'm hearing (oh, the things we do for our baby's). It's hard to capture exactly what I hear in real life, but right after I shift into 2nd (about 4 seconds in), under load at about 3000 rpm, there seems to be this new low/throaty noise that I haven't heard. Keep in mind, I am not familiar with how this bike "should" sound, but it's never sounded like this. I'm a noob, but I counteract my lack of knowledge with care and research: I know everything went back together right, and nothing got bent,banged, or dropped. I've been talking to a few car guys and when I described the sound as wood blocks clapping together, they thought it might be a wrist pin or a crankshaft bearing .
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07-09-2012, 01:53 PM
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#2 |
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De Oppresso Liber
Joined: Jul 2006
Location: Central New Mexico, 7420ft above sea level
Oddometer: 30,789
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Um no, sounds like you are riding thur an underwater grotto. And that sound is like a bad muffler or something.....strange. Exhaust leak or pluggage or something?
__________________
"I claim to be frightened of horses but do so only to get out of attending parades. It's peculiar but ...it works. The Horses get it. Straight Out Da Trailah! |
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07-09-2012, 02:20 PM
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#3 |
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Studly Adventurer
Joined: Oct 2009
Location: Portland, Oregon
Oddometer: 758
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Might be in the transmission if it's only heard after the shift in to second.
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'71 r75/5 |
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07-09-2012, 02:44 PM
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#4 |
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ShadeTreeExpert
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 5,216
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What sound?
You're gonna have to find some old fart to ride next to you on the highway to listen. Sounds don't work very well on the interwebs.
__________________
Never memorize something you can look up. ---Albert Einstein |
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07-09-2012, 02:52 PM
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#5 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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Excuse my primitive recording techniques. I did put a low mid frequncy boost at about 200Hz with Protools to emphasize the undesirable noise...
I can look into a muffler malfunction, I had that off- obviously. Tips on diagnosing a leak/ pluggage? Its not only into 2nd gear, that was more of a reference point- it shows up when I'm at operating temperature and under load. |
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07-09-2012, 02:56 PM
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#6 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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True disston, I figured it was worth a shot as apposed to trying to describe it... Fail! I'm just concerned I'd be damaging something along the way.
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07-09-2012, 03:03 PM
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#7 |
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ShadeTreeExpert
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 5,216
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Yes it was a good try. Just always this problem with describing sounds and now-a-days producing them with low tech/high tech machines. What is the world coming too?
Some things take miles to figure out. I have had to ride my bike for hundreds of miles just to think about this.
__________________
Never memorize something you can look up. ---Albert Einstein |
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07-09-2012, 03:44 PM
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#8 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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guess I'll keep scratching and recheck my work... Somehow I've turned my bike into a diesel tractor?!?!?!?
Hopefully it's just valve clearance and end float that are set too tight. Have mercy on my soul (and my poor forgotten gf and dog) if I gotta tear it down again. Or, at this point, whoever's gotta do it- this may require mechanical expertise that is off my radar
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07-09-2012, 03:54 PM
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#9 |
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A GPS? Huh?
Joined: Nov 2010
Location: Vermont
Oddometer: 239
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When was the last time you synchronized your carbs? Did you sync the cables off-idle as well?
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07-09-2012, 04:10 PM
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#10 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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Those magical little things do make quite a difference. Good point, that'll go on the recheck list tomorrow, along with all that fun timing stuff. I'm beginning to wonder why I ever put the front cover back on...
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07-09-2012, 04:37 PM
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#11 |
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ShadeTreeExpert
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 5,216
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Well I can tell you from personal experience that if you leave the front cover off you end up getting the points wire caught in the advance unit and stranded miles from home. Fortunately I had enough wire left to twist it together and get back home. Only bad part was I was broken down in front of some Red Necks house and they looked almost as Neanderthal as the people at my house. This has happened to me a couple of times (not the same place). I now claim to be an expert on the arrangement of all the little pieces in the timing chest.
__________________
Never memorize something you can look up. ---Albert Einstein |
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07-09-2012, 06:18 PM
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#12 |
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A GPS? Huh?
Joined: Nov 2010
Location: Vermont
Oddometer: 239
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You may be a simple victim of new guy paranoia. Typical symptoms include hearing odd noises....sometimes when the engine isn't even running. This condition is typically acute if the sufferer is anal retentive or a victim of obsessive compulsive disorder. Rent a decent movie, have a good night sleep, and wait for cooler weather. Airheads always run better in cooler weather.
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07-09-2012, 07:00 PM
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#13 |
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More tacos than you
Joined: Mar 2008
Location: Manzanillo MX, occasionally Seattle
Oddometer: 5,197
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The best way to fix that noise is with earplugs. Sounds fine. Ride it and get used to the symphony of regular airhead noises. There are a lot of them. Get a 5-10 thousand miles down and you should have a feel for what's normal and what isn't. These bikes make a little more clattery racket than most bikes even when in a perfect state of tune.
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R80ST Gets The HPN Treatment Ducati Pantah 500SL Rebuild Seattle to TDF on an airhead WTB R100R Mystic sidestand and mount. |
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07-09-2012, 07:40 PM
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#14 |
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Confirmed Curmudgeon
Joined: Sep 2008
Location: backwoods Alabama
Oddometer: 4,008
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Could be that you're overthinking this.
Run the bike over to Tom Cutter at the Rubber Chicken Racing Garage in Yardley, PA. I'm sure he'll be glad to listen and advice you.
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'73 R60/5 Toaster |
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07-09-2012, 09:35 PM
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#15 |
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Bavarian Motor Pie
Joined: Mar 2012
Location: philadelphia, pa
Oddometer: 51
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"...some Red Necks house and they looked almost as Neanderthal as the people at my house." Classic, love it. Removing the ground wire's a pain, but lesson learned: those 3 nuts couldn't be any easier... But it does run just fine without that damn horn....
![]() "...victim of new guy paranoia. Typical symptoms include..." Have we met? This pretty much sums up my alter-airhead-ego (although my teachers, mother, employers, and girlfriend would state otherwise). "Could be that you're overthinking this. Run the bike over to Tom Cutter..." Jeez I hope you're right. Hopefully Tom can soothe my nerves and isn't too far away- Yardley's at least about 30 min (too far?). I think my neighbors will call the cops if they see me in my pj's with my headlamp, Clymer's, oil pan, and wrenches- I guess it can wait till tomorrow. Thanks all!!! |
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