BMW K bikes (Bricks)

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1Back to top Go down   K100 power Empty K100 power Sun Jul 04, 2021 9:44 pm

César Santos

César Santos
active member
active member
Hi

I bought my K100 some time ago, I had it overhauled, because first I like to have the mechanics ok, then comes the aesthetic.
I have some doubts, even because I don't know anyone with a K100.
Is the bike too short of transmission? I go on 5ªgear at 80km/h and it seems to be running out..., is it normal? The bike doesn't seem to have easy going up above 4/5000rpm, I think it doesn't go up... 120Km/h seems a lot even for this engine, is it really like that or could

The bike have some problem?


Thanks

    

2Back to top Go down   K100 power Empty Re: K100 power Sun Jul 04, 2021 10:38 pm

brickrider2

brickrider2
Life time member
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Cesar, your motorcycle most certainly has a problem.  The engine in my old K100RS was just waking up at 4.5 k rpm.  Yours should continue building power to redline.  
What have you done to correct this?  What do the spark plugs look like?  Does the engine seem to run smoothly, or does it have significant vibration?  What about the timing?  Is it properly set? Did you measure compression in the cylinders?

If the engine was rebuilt, did it perform as it should immediately after that work? Or, is this problem that suddenly arose only much later?

The only problem I ever had with my K100RS was caused by the plug on the left front underside of the tank - the one that provides electricity to the fuel pump.  It would sometimes make intermittent contact that stopped the fuel pump.  Some replace that troublesome connector entirely.  I solved my problem with some cleaning of the contacts and stretchy silicon tape.   Smile


__________________________________________________
1996 K1100LT
    

3Back to top Go down   K100 power Empty Re: K100 power Mon Jul 05, 2021 5:49 am

César Santos

César Santos
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active member
I don't know the bike's history, I bought it recently, I just have some invoices for previous maintenance.
The only repair I had, apart from a general overhaul, was to put the water/oil pump shaft and seals, it's ok.
The engine seems to work fine to me, it just doesn't go up in rpm and there really are too many vibrations, which I thought were from the structure (it's an LT and has some damaged plastics).
Could the vibration be caused by engine failure?

It looks just right whem ramping up, but the bike doesn't go past 4/5000 rpm.
What can I analyze?
Thanks

    

4Back to top Go down   K100 power Empty Re: K100 power Mon Jul 05, 2021 8:10 am

Laitch

Laitch
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Life time member
César Santos wrote:What can I analyse?
The list of systems to analyze is a long one. Start with the most simple. Can you describe how completely the moto was disassembled for inspection by the mechanic?

When you twist the throttle grip, you should feel immediate tension as the grip engages the cable. Look at the throttle bodies. 

The throttle cable connected to the throttle grip also connects to a rotating mechanism between two of the throttle bodies. Twist the throttle grip or push the disk with your finger to determine whether some part of the throttle bodies is obstructing the mechanism's rotation, the cable is faulty, or if the mechanism needs lubrication. Sometimes, one of the clamps on the rubber tubes on top of the throttle body next to the throttle cable mechanism will be installed in a way that blocks full rotation of the throttle cable mechanism.

Check those items and tells us what you discover.


__________________________________________________
1995 K75 81,000 miles
K100 power Usa-lo10
    

5Back to top Go down   K100 power Empty Re: K100 power Mon Jul 05, 2021 8:10 pm

César Santos

César Santos
active member
active member
Hi,

I just checked the entire throttle system, everything seems fine, tension from the very first moment and it goes all the way around, it doesn't seem like that.
But once again I was listening to the engine working and everything seems fine, very right and the rpm goes up well up to 4500/5000, from then on I find it difficult.
I spoke on the phone with the mechanic, he told me about fuel pressure, sometimes a plastic tube gives way... I'll keep testing until I can go there...
Any more suggestions?

Thanks

    

6Back to top Go down   K100 power Empty Re: K100 power Mon Jul 05, 2021 9:53 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Have you checked the ignition timing?  The Hall Effect sensors are mounted on a plate at the front of the engine.  The plate can be rotated so it aligns with an opening in the cover it is mounted in.  If the timing is off, it can be difficult to rev the engine beyond a certain point.

While I've never heard of it, I wonder if the rev limiter is acting up. It does seem odd that the engine won't rev past 4500 rpm which is approximately half of the rev limiter setpoint.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

7Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 10:47 am

KapteeniMahtava

KapteeniMahtava
active member
active member
Hi,
I have same problem with my K1. Lost of power above 5000rpm.
It seem to help if pump the throttle at high rpm. It feels like it is lacking fuel.
I have just done top end over haul with new Rubber hoses and tubes.

    

8Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 11:05 am

César Santos

César Santos
active member
active member
Hi
And managed to solve the problem?

    

9Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 11:12 am

KapteeniMahtava

KapteeniMahtava
active member
active member
No not yet. Just did the first drive after overhaul. Might be fuel or timing issue. Going check these next week..

    

10Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 11:40 am

Laitch

Laitch
Life time member
Life time member
I alluded in Reply#4 of this thread to this condition possibly being the cause of dismay. Take a closer look, really close. Laughing


__________________________________________________
1995 K75 81,000 miles
K100 power Usa-lo10
    

11Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 12:27 pm

KapteeniMahtava

KapteeniMahtava
active member
active member
Laitch wrote:I alluded in Reply#4 of this thread to this condition possibly being the cause of dismay. Take a closer look, really close. Laughing
This something to look at. Thanks!
When I took the cylinderhead of I had ziptied chain to sprockets, bu have little suspicion that I have stuck chain tensioner.

    

12Back to top Go down   K100 power Empty Re: K100 power Wed Jul 07, 2021 12:51 pm

KapteeniMahtava

KapteeniMahtava
active member
active member
Laitch wrote:I alluded in Reply#4 of this thread to this condition possibly being the cause of dismay. Take a closer look, really close. Laughing
This is it, your were right! It does hit those clams..

    

13Back to top Go down   K100 power Empty Re: K100 power Sun Jul 11, 2021 2:01 pm

César Santos

César Santos
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active member
hi

It's not my problem, I've been checking and everything is ok.

Keep looking..., suggestions???

    

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