BMW K bikes (Bricks)

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1Back to top Go down   Vibration Empty Vibration on Sat May 19, 2012 9:56 pm

Avenger GT

Avenger GT
Life time member
Life time member
My 1986 K100RT engine has always been very smooth, with just a very slight tingle around 3700 to 3800 revs. In the last week it has become very rough, vibrating enough to rattle the side stand against the exhaust, and even causing the fairing to vibrate when you rev it in neutral and close the throttle, and also on the overrun. The vibration seems worse around 2500 revs, but is there through the rev range, or at least up to 4500 revs ( I didn't feel like pushing it any harder in case something went bang ). Power doesn't seem to be affected, and there is no problem with starting, and it idles around 1100 revs which it has always done. Investigations are ongoing. 😕

    

2Back to top Go down   Vibration Empty Re: Vibration on Sat May 19, 2012 10:34 pm

RicK G

RicK G
VIP
VIP
I would give it the inlet leak test first then a compression test. Does it increase with engine speed or road speed?


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

3Back to top Go down   Vibration Empty Re: Vibration on Sat May 19, 2012 10:45 pm

Avenger GT

Avenger GT
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Engine speed, road speed doesn't make any difference.

    

4Back to top Go down   Vibration Empty Re: Vibration on Thu May 24, 2012 1:54 pm

Avenger GT

Avenger GT
Life time member
Life time member
Checked so far;

Leak test on throttle body rubbers etc, OK.

Compression, 160psi on Nos. 1,2,3 cylinders, 170 on No 4.

Plug leads, plugs, coils, OK.

Valve clearances, OK.

The only thing I have found not right is No 4 inlet cam lobe. The leading edge (side ?) of the tip of the lobe is worn, leaving a distinct ridge just as it goes over the top. Could this be causing the vibes?? Time to crack open the rocker cover on the spares bike and see what's in there. :-c:

    

5Back to top Go down   Vibration Empty Re: Vibration on Thu May 24, 2012 8:47 pm

RicK G

RicK G
VIP
VIP
That's not a very good thing to see on a cam lobe. I would replace the cam and don't use the shim again. Replace the spring as it could be where the problem startes with a bit of chatter.
I would not say for sure that is where the vibes are comming from but it could well be


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

6Back to top Go down   Vibration Empty Re: Vibration on Thu May 24, 2012 8:56 pm

charlie99

charlie99
VIP
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yep sounds like a stuck lifter ,,,could some thing like dirt - sand have gotten in the lifter bore preventing it from rotating ? or a blocked oil path out one of the camshaft saddles ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OVibration Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

7Back to top Go down   Vibration Empty Re: Vibration on Fri Jul 06, 2012 9:37 pm

Avenger GT

Avenger GT
Life time member
Life time member
Only got back to this today. Removed the cam cover on the spares bike to find that the very part I need ( the inlet camshaft ) is broken between numbers 1 & 2 cam lobes, so I have a single cylinder K bike. No wonder the thing made a racket for the couple of seconds that I ran it. The cam lobes look blue, as if they have been run without oil. My guess is that the shaft seized in the bearings and sheared under the 2nd bearing cap. Now I have to hunt down an inlet cam.

    

8Back to top Go down   Vibration Empty Re: Vibration on Fri Jul 06, 2012 10:50 pm

charlie99

charlie99
VIP
VIP
bugga !!!

hope you find one soon gt ...

ill bet that most folks want sell the whole motor though ...i wonder if motorworks ot the bins have wrecks that might contain what you need ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OVibration Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

9Back to top Go down   Vibration Empty Re: Vibration on Fri Jul 06, 2012 10:57 pm

Avenger GT

Avenger GT
Life time member
Life time member
Motorworks list used camshafts for £29, so I will call them tomorrow and see what they have.

    

10Back to top Go down   Vibration Empty Re: Vibration on Sun Jul 08, 2012 8:00 pm

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
Avenger sorry to hear your problem. Hope you get it sorted soon. Motorworks excellent. Got my ICU from them, ordered on Wednesday arrived following Monday and was as expected.

I think 88KE might be interested in a run sometime, if we can have all 3 Ks running at the same time! Any more takers out there,? Any thoughts on somewhere to meet up? South east? Waterford? Lobster Pot in Carne [Wexford] is a really nice run and the lunch is excellent. Some nice places in Cashel too.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

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