K11 Owners Group

Photoman · Joined: 03 Nov 2007 Posts: 10 Location: Newport S.Wales UK

I know a lot has been written about K bike vibrations, over the years, but I would appreciate some more advice on the issue. My 93 K11RS needs sorting - at high speeds my hands are going numb - not good! I love this bike in every respect, it's a superb machine, but I have to sort out the vibes - they are spoiling a near perfect bike. Its done 36800 miles and does seem to be getting slightly better with regular high speed runs. Any advice would be welcomed. Mark (photoman)

abreeze · Posted: Sun May 11, 2008 8:45 pm Post subject:

The thing that works the best is to Sync the Throtle Bodies. BMW says not to do this(know one knows why), but many members have had great sucess with this.

At 35K your bike is due, and it really works....

Mystic Red · Posted: Sun May 11, 2008 9:57 pm Post subject:

Mine still has a wild buzz at 4K, in the clutch lever, no where else. I just try not to live there. Twisted Evil

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Scott Hespelt, '94 K11LT
K11 OG #466

Shoganai · Posted: Sun May 11, 2008 10:15 pm Post subject:

Flying Duck · Posted: Tue May 13, 2008 7:59 am Post subject:

Flying Duck · Posted: Tue May 13, 2008 8:02 am Post subject:

Shoganai · Posted: Tue May 13, 2008 8:22 am Post subject:

Cool, I would like that.

Very Happy

_________________
1993 K1100RS aka The Shop Whore
1994 K1100RS aka Blue Streak

The long road is a rainbow and the pot of gold lies there.
So slip the chain and I'm off again,
You'll find me everywhere. I'm a Rover. - JT

Nana korobi ya oki

Rolfieh · Joined: 14 Apr 2008 Posts: 11

I have sychned by bodies (spent £55 on a Carbtune to do it), put injection cleaner through the fuel, changhed the air filter, replaced the plugs (Bosch) and still I have bad vibes above about 4k. By 100 MPH (6k) my fingers are starting to go numb (as well as vibes through the saddle and foot rests). I have only owned one 4 cylinder bike before (FJ1100) which was no where nears as bad nand my other current bike is a TDM 900 which has no vibes at all. I must admit that I am currently thinking of selling the BMW unless I can sort this problem out
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Rolfieh

1993 K1100RS

abreeze · Posted: Tue May 13, 2008 6:02 pm Post subject:

Flying Duck · Posted: Tue May 13, 2008 7:26 pm Post subject:

The brass screws are what are used to synch the TBs.

Please reread your post - it seems to imply that BMW recommends not synching the TBs:

RAL88 · Posted: Tue May 13, 2008 7:34 pm Post subject:

BMW recommends not synching the butterflies in the throttle bodies. This entails loosening the screws between the throttle bodies(the ones with the blue paint on them) to adjust the butterflies. I have an article I got in 2002 off of the K tech page on IBMWR which explains how to do the butterfly sync. I synched the butterflies on my bike before I synched it by the brass screws with no problems.
_________________
Rich

"If it ain't broke, take it apart and make it work better"
*************
'96' K1100LT-SE
'97' R850GS-R

BMGraeme · Posted: Wed May 14, 2008 2:14 pm Post subject:

I have just bought a Morgan Carbtune and it's the easiest thing in the world to balance the throttle bodies using the brass screws as FD says just 20 minutes tops. Having set the idle sync in this way I found that all 4 cyclinders remained in sync all the way up the rev range so I don't think it could be set better by fiddling with the butterfly sync. Maybe I was just lucky. When my K11 had 6K miles on the clock I got the numb thumb on my right hand but now with 23K I don't suffer at all. Sure the vibe is still there at 4K revs but for me it's not an issue anymore.

You do need to make sure your valve clearences are correct and you have good plugs etc before you do the sync otherwise you are masking other problems.

Is it possible a previous owner removed or compressed the rubber mountings on the handlebars and more vibration is getting through? Are the handlebar end weights stock or non-OEM?
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1980 CB900FA
1994 K1100RS
2008 R1200GSA

Photoman · Joined: 03 Nov 2007 Posts: 10 Location: Newport S.Wales UK

thanks for the info guys, I will sync the throttle bodies - I do need to get the valve clearances checked as well - The vibes are bad @ 4000 rpm (just under) which seems to be a 'usual' bad spot. However from 90 mph upwards they are bad again. I guess the only way to attempt to sort it is to one thing at a time. How about handlebar weights - i have heard they can be effective. Ride safe, Mark (photoman)

BMGraeme · Posted: Fri May 16, 2008 7:47 am Post subject:

I think the 4K vibes are consistent with most owners but not above that. Maybe take some time and go over the bike to make sure everything is torqued up right especially the exhaust mountings. While your there check the condition of the pipe welds as you may have a small crack. 36K is about right for checking the valve clearances.
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1980 CB900FA
1994 K1100RS
2008 R1200GSA

CheapJapCopy · Posted: Fri May 16, 2008 1:36 pm Post subject:

SugarHillCTD · Posted: Fri May 16, 2008 8:24 pm Post subject:

Really haven't noticed excessive vibration. Our '93 K1100RS is just slightly more "buzzy" than the '81 Honda 900F Supersport that we had back in the 80's, but not very bad at all. So it might be tuning, sync, and/or just each individual bike's own personality??
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John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

Midlife K-risis · Flying Brick Rider Joined: 19 Jun 2003 Posts: 166

When I first got my 94 K1100RS five years ago, I couldn't live with the buzz. I went through all the tips given on this forum and the ones that helped the most were synching the throttle bodies and properly torqueing the exhaust bolts. It's still buzzy, but nowhere near as bad as it used to be. I had a BMW tech ride it, and he said it was the smoothest K-bike he'd ever ridden Shocked

So, I guess this is as good as it's gonna get. Oh yes, another thing that can make a difference: check the rubber handle bar mounts. Mine had deteriorated, so I replaced them and put some larger rings on them, so that they don't cut into the rubber over time. Big difference! The handlebars sit up slightly higher, but that's not a bad thing!
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Silk Blue '94 K 1100 RS.

mike toon · Posted: Wed Jul 02, 2008 8:49 pm Post subject:

Could someone explain how syncing the carbs will affect vibration at half throttle. Lets say the carbs are at slightly different opening positions. (52%, 49%, 47% and 53%) I contend each cylinder will do a slightly different share of the total output from the crankshaft, but not cause a vibration. At idle it's a different story.
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Current Bikes
1993 K1100LT
1976 GL1000 Naked
1981 GL1100 Naked
2000 DR650 Dual Sport