BMW K bikes (Bricks)

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1Back to top Go down    Noise just off idle on Wed Mar 01, 2017 11:17 am

wilcom

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I noticed  what seemed to be a noise off idle.

 That sound is what I heard off idle when I put the "new to me "1989 K100RS with 88K miles on the clock in storage for a couple of months before I could be riding it much.

I am reading almost all the posts listening intently to all you folks that have amassed so much knowledge about these k Bikes when I read from "Point 75".......

"
The rattle may be a combination of things.

First, the throttle body balance at idle is probably off and causing uneven firing.  You can't really hear it, but it's there."







are we talk'n about the same sound?



Last edited by wilcom on Sat Apr 29, 2017 3:20 pm; edited 1 time in total


__________________________________________________
Joe Wilkerson
Telephone man with a splash of Data
Menifee, CA
1989 K100RS SE


past
1979 BMW R65
1980 BMW R65
1982 BMW R80RT (Gas hog)
1974 BMW R90/6
1972 BMW R75
1964 BMW R50 Earles forks( as reliable as a hammer)
2009 Buel XB12R (the FI sucked)
1999 Buell  (Yeah! a carburetor)
2005 Suzuki Bandit 1200
1991 Kaw ZX-11 OMG
1966 Norton 750 (had to have a chase car for anything over 5 miles)
1961 Norton 650' (see above)
1964 Honda 305 Superhawk
and a dozen or so I have forgotten about..........
    

2Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 12:47 pm

Laitch

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@wilcom wrote:are we talk'n about the same sound?
These bikes will make a hellacious rattle if they are lugged. They want revs. Use lower gears and give plenty of throttle on takeoff—not wheelie throttle though. That rattle might go away if you do that.


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1995 K75T 68,000 miles
    

3Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 12:53 pm

wilcom

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@Laitch wrote:
@wilcom wrote:are we talk'n about the same sound?
These bikes will make a hellacious rattle if they are lugged.

This sound was just off idle while out of gear. just a soft blip of the throttle and right off idle.



Last edited by wilcom on Sat Apr 29, 2017 3:22 pm; edited 1 time in total


__________________________________________________
Joe Wilkerson
Telephone man with a splash of Data
Menifee, CA
1989 K100RS SE


past
1979 BMW R65
1980 BMW R65
1982 BMW R80RT (Gas hog)
1974 BMW R90/6
1972 BMW R75
1964 BMW R50 Earles forks( as reliable as a hammer)
2009 Buel XB12R (the FI sucked)
1999 Buell  (Yeah! a carburetor)
2005 Suzuki Bandit 1200
1991 Kaw ZX-11 OMG
1966 Norton 750 (had to have a chase car for anything over 5 miles)
1961 Norton 650' (see above)
1964 Honda 305 Superhawk
and a dozen or so I have forgotten about..........
    

4Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 12:57 pm

Laitch

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@wilcom wrote:This sound was just off idle while out of gear. just a soft blip of the throttle and right off idle it rattled a bit. a rattle that sounded like rod bearings in the old days
Well, let's leave the old days behind. Post an audio file so we can all have a listen.  Smile


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1995 K75T 68,000 miles
    

5Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 1:04 pm

wilcom

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@Laitch wrote:
@wilcom wrote:This sound was just off idle while out of gear. just a soft blip of the throttle and right off idle it rattled a bit. a rattle that sounded like rod bearings in the old days
Well, let's leave the old days behind. Post an audio file so we can all have a listen.  Smile

If you have never tried to buy a 52 Chevy the sound may not be relevant and i don't think it would be picked up in an audio file.

When I bring the bike out of storage this summer I will see what the throttle body adjustment will do for the sound I'm hearing.


__________________________________________________
Joe Wilkerson
Telephone man with a splash of Data
Menifee, CA
1989 K100RS SE


past
1979 BMW R65
1980 BMW R65
1982 BMW R80RT (Gas hog)
1974 BMW R90/6
1972 BMW R75
1964 BMW R50 Earles forks( as reliable as a hammer)
2009 Buel XB12R (the FI sucked)
1999 Buell  (Yeah! a carburetor)
2005 Suzuki Bandit 1200
1991 Kaw ZX-11 OMG
1966 Norton 750 (had to have a chase car for anything over 5 miles)
1961 Norton 650' (see above)
1964 Honda 305 Superhawk
and a dozen or so I have forgotten about..........
    

6Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 1:20 pm

Point-Seven-five

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Unless your bike has been to hell and back a couple of times with no oil I would doubt that you have a bad rod bearing.  I am on two K bike forums and have read threads for at least the past 4 years and so far I have yet to see a thread or post about a thrown rod.  There was one a while back where someone had bent a rod on a hydrolocked cylinder, and another where an engine swallowed a valve. 

What you are describing is probably alternator knock or slack in the output shaft gear.  Alternator knock is pretty easy to fix, while the output gear slack requires removing the engine and some tear down. 

First thing is to balance the throttle bodies.  That will improve things, and should be done anyway.  Then check the alternator by removing it and starting the engine.  If it's the alternator rubbers, the noise will go away.

Even when everything is nice and tight these engines make a lot of noise.  Like high revs at highway speeds, most of us just get used to them.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

7Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 1:37 pm

Laitch

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@wilcom wrote:
If you have never tried to buy a 52 Chevy the sound may not be relevant and i don't think it would be picked up in an audio file.
I owned fastback '49 Chevy coupe with a straight six. It was what I used to haul the string bass, guitars, harmonicas, weed, cheeseburgers, jugs and personnel of the band from gig to gig in the late '60s.

My philosophy today is if it can't by heard on an audio file it, it won't bother me.


__________________________________________________
1995 K75T 68,000 miles
    

8Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 3:52 pm

Point-Seven-five

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On the '56 V8 my friend had, you just removed the spark plug in the cylinder that knocked.  When you got down to 4 cylinders you emptied the car except for a screwdriver to remove the license plate when you couldn't do 30mph anymore.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

9Back to top Go down    Re: Noise just off idle on Wed Mar 01, 2017 5:47 pm

Laitch

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Life time member
@Point-Seven-five wrote:. . . you emptied the car except for a screwdriver to remove the license plate when you couldn't do 30mph anymore.
(o)


__________________________________________________
1995 K75T 68,000 miles
    

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