BMW K bikes (Bricks)


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krambo

krambo
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My ex police K1100 LT recently suddenly lost power on the dual carriageway and seemed to be only running on 3 cylinders.  I managed to limp the bike home and park it up pending further investigation at a later date.  I have since discovered that there is zero compression on the number 3 cylinder (assuming cylinder 1 at the front of the engine).  Is this something that any of the knowledgeable members of this forum could advise me on and suggest possible ways forward ?

Thanks in anticipation  Sad 

krambo


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." K1100LT with no compression on cylinder 3 - most likely cause ? Uk-bmw12
http://www.its-personal.net
    

Rick G

Rick G
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My K1100 did the same thing when it broke the edge off an exhaust valve.
Have a feel round the top of the piston for a possible hole and if that is the case then it would be blowing a fair bit of smoke.
See if you can borrow an endescope that will go in the plug hole and get a look at the valves they could be bent or broken like mine was, you may also need to look in through the exhaust port at the back of the valves.
Check the valve clearances to see if any have opened up which would mean a bent valve.
It is possible that a head gasket has blown but if it was into the oil or water then that would show in the cylinder and if it were between the cylinders it would affect 2 cylinders.
Next alternative is to remove the head and have a look.
Feeding compressed air into the cylinder will tell you where it is leaking to as you will feel the air coming out the exhaust,  inlet tract oil or water system.


__________________________________________________
"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 1999 K1100 LT with a Big Block 1200
    

krambo

krambo
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RicK G wrote:My K1100 did the same thing when it broke the edge off an exhaust valve.
Have a feel round the top of the piston for a possible hole and if that is the case then it would be blowing a fair bit of smoke.
See if you can borrow an endescope that will go in the plug hole and get a look at the valves they could be bent or broken like mine was, you may also need to look in through the exhaust port at the back of the valves.
Check the valve clearances to see if any have opened up which would mean a bent valve.
It is possible that a head gasket has blown but if it was into the oil or water then that would show in the cylinder and if it were between the cylinders it would affect 2 cylinders.
Next alternative is to remove the head and have a look.
Feeding compressed air into the cylinder will tell you where it is leaking to as you will feel the air coming out the exhaust,  inlet tract oil or water system.
Thanks for the comments Rick.  There was no noticeable smoke coming from the exhaust/engine and no extraneous mechanical noises etc. when this happened.  Pretty certain that it isn't the head gasket as all other cylinders show good compression.  I reckon my only realistic option is to remove the head and take a look.  I have been trying to avoid having to do this as I have a very limited workspace in which to carry out strip down work under cover and cannot afford to get a pro to look at it just now.  Thanks again for your input  Sad


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." K1100LT with no compression on cylinder 3 - most likely cause ? Uk-bmw12
http://www.its-personal.net
    

Rick G

Rick G
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If you do take the head off be careful to prevent the lifters from falling out on the exhaust side as they face down and slowly fall out of their bores and can get mixed up.


__________________________________________________
"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 1999 K1100 LT with a Big Block 1200
    

92KK 84WW Olaf

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This happened me once on a car, ran all the checks, exhaust valve was the problem. Head off job but took the opportunity to do a few other jobs at the same time. On the K I would replace the exhaust studs. Curious though as to what happened, Ks are very reliable engines.


__________________________________________________
1992 K100LT 0193214 Bertha 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 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 48,061 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 61,190 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

krambo

krambo
Life time member
Life time member
Thanks for all the comments/advice so far folks  Wink


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." K1100LT with no compression on cylinder 3 - most likely cause ? Uk-bmw12
http://www.its-personal.net
    

88

88
Life time member
Life time member
RicK G wrote:
Feeding compressed air into the cylinder will tell you where it is leaking to as you will feel the air coming out the exhaust,  inlet tract oil or water system.

I'm starting to investigate the reason for being recovered home yesterday. It sounded similar to a cracked valve which I only experienced once before on a car and was hopeful it might be just a gammy header but having swopped the exhaust system this afternoon I can rule that out. 

How is the compressed air best fed into the Cyliner Rick G? I'd like to have a go before stripping the head.


__________________________________________________
K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log1188....May contain nuts!K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

K1 - 1989 - AKA Titan (unique K1/K1100RS hybrid by Andreas Esterhammer)
K1100RS - 1995. AKA Rudolf Von Schmurf (in a million bits)
K100RS - 1991 AKA Ronnie. Cafe racer project bike
K75RTP - 1994
K75C - 1991 AKA Jim Beam. In boxes. 
K1100LT 1992 - AKA Big Red (gone)
K100LT - 1988 - AKA the Bullion brick. Should never have sold it.
    

BobT

BobT
Life time member
Life time member
Have you carried out a compression test Will????

    

88

88
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No Bob....lacking the gadgetry!


__________________________________________________
K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log1188....May contain nuts!K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

K1 - 1989 - AKA Titan (unique K1/K1100RS hybrid by Andreas Esterhammer)
K1100RS - 1995. AKA Rudolf Von Schmurf (in a million bits)
K100RS - 1991 AKA Ronnie. Cafe racer project bike
K75RTP - 1994
K75C - 1991 AKA Jim Beam. In boxes. 
K1100LT 1992 - AKA Big Red (gone)
K100LT - 1988 - AKA the Bullion brick. Should never have sold it.
    

BobT

BobT
Life time member
Life time member
88 wrote:No Bob....lacking the gadgetry!
A Gunson one is about £25 in the UK, I am sure that they have them over there, an essential tool. Mine is about 20 years old now.

    

92KK 84WW Olaf

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BobT wrote:
88 wrote:No Bob....lacking the gadgetry!
A Gunson one is about £25 in the UK, I am sure that they have them over there, an essential tool. Mine is about 20 years old now.
My tool is the same age as me. lol!


__________________________________________________
1992 K100LT 0193214 Bertha 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 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 48,061 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 61,190 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

Rick G

Rick G
admin
admin
88 wrote:
RicK G wrote:
Feeding compressed air into the cylinder will tell you where it is leaking to as you will feel the air coming out the exhaust,  inlet tract oil or water system.

I'm starting to investigate the reason for being recovered home yesterday. It sounded similar to a cracked valve which I only experienced once before on a car and was hopeful it might be just a gammy header but having swopped the exhaust system this afternoon I can rule that out. 

How is the compressed air best fed into the Cyliner Rick G? I'd like to have a go before stripping the head.
I made a compressed air adapter from a busted spark plug by breaking the porcelain out and welding an air fitting to it.


__________________________________________________
"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 1999 K1100 LT with a Big Block 1200
    

BobT

BobT
Life time member
Life time member
92KK 84WW Olaf wrote:
BobT wrote:
88 wrote:No Bob....lacking the gadgetry!
A Gunson one is about £25 in the UK, I am sure that they have them over there, an essential tool. Mine is about 20 years old now.
My tool is the same age as me. lol!
If it is that old Olaf, it is probably a tool for getting stones out of horses hooves as motorbikes weren't invented when you were born!  Why is it that so many school kids had a penknife with a tool for the horses when we never went near horses?

    

Inge K.

Inge K.
VIP
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RicK G wrote:
88 wrote:
RicK G wrote:
Feeding compressed air into the cylinder will tell you where it is leaking to as you will feel the air coming out the exhaust,  inlet tract oil or water system.

How is the compressed air best fed into the Cyliner Rick G? I'd like to have a go before stripping the head.
I made a compressed air adapter from a busted spark plug by breaking the porcelain out and welding an air fitting to it.


Or get you one like this from the local automotive tool shop (or the net).

K1100LT with no compression on cylinder 3 - most likely cause ? Adapte10


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

15Back to top Go down   K1100LT with no compression on cylinder 3 - most likely cause ? Empty You can blow air in, but then what? Fri Oct 21, 2016 9:53 pm

Bumblebee

Bumblebee
Silver member
Silver member
Aside from motorcycles I also work on airplanes, the kind with reciprocating engines.  To test compression the propeller is rotated (with the top spark plugs out) until you get to TDC.  At this point you install a spark plug adapter and connect the differential compression tester.  This gizmo has two pressure gauges on either side of an .040 orifice, you slowly apply pressure to the tester (while holding the prop) and adjust the valve for 80 PSI on the hose side, then observe the gauge on the cylinder side, if you have a good one the reading on the gauge will be within 10% of the hose side.

I really don't see how useful a single gauge "differential" compression tester intended for advanced shade tree mechanics are going to be of too much help.

Cars/bikes, the idea here is to crank the engine while holding the throttle wide open.  The tester is a simple gauge with a memory that reads the maximum pressure developed while cranking the engine around a few times until the highest pressure is noted and it's not going any higher. (*gasp*) Some gauges have a rubber cone you hold in the spark plug hole with your thumb, not so good, the better ones have a hose and a spark plug adapter, better.  Compare with the manufacturers specification, if it's above the magic number you are good to go.  If you do all four (or more) of them and the readings differ from jug to jug this shows a problem.On a healthy engine the differential from cylinder to cylinder should all be within 10%  On a high mileage engine they can be as high as 30% and it will still run okay.  Anything more than that not so good.

A new way is to use a special tool that is a current clamp on the starter motor lead plus a sensor on the #1 spark plug, pull all the plug wires, you don't want the engine to start. As the engine cranks various amounts of juice will be drawn by the motor depending on where the engine is in the cycle (compression takes the most) and comparing the graph.  With a good 4 cyl. engine you'll see something like 210 - 205 -210 - 75 amps.  The last cylinder in the firing order only drew 75 amps, showing that this cylinder was exhibiting low compression because the starter didn't need as much current to push through compression on that one .  The first time I saw this method used was with my old Ford pickup that had developed a poor idle, This was the Ford approved method to testing.  Sure enough I had a leaking valve that didn't show up with my conventional shade tree methods.

If you know what you are listening for you can spot a low jug as the engine is cranking.  Very handy junk yard technique when selecting an engine that's on the ground.

*Now for something you'll really like!*

Low compression on your K-Bike, first pull the valve cover and check the valve lash, if you have developed a valve issue you'll likely find no valve clearance (burned/broken valve), or if the spring is broken it will be vary obvious as there will be huge clearance. On burned valve, if the valve lash is allowed to degrade to "zero" the valve will be held open more and more, until the flame front whooshes (that's a technical term) past the valve head causing it to become severely overheated and melt.  On engines of yesteryear it was not uncommon to see erosion on the valve seat that allows leakage resulting in eventual Barbeqvalve syndrome.

So, that's what I know...

Da Bee - AKA John.

Did this make any sense??

http://Bugsmashers.org/phpbb
    

Rick G

Rick G
admin
admin
Inge K. wrote:
RicK G wrote:
88 wrote:

How is the compressed air best fed into the Cyliner Rick G? I'd like to have a go before stripping the head.
I made a compressed air adapter from a busted spark plug by breaking the porcelain out and welding an air fitting to it.

Or get you one like this from the local automotive tool shop (or the net).

K1100LT with no compression on cylinder 3 - most likely cause ? Adapte10
Mine is cheaper Razz


__________________________________________________
"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 1999 K1100 LT with a Big Block 1200
    

88

88
Life time member
Life time member
That makes sense Bee/John. Interesting about current draw. 

I think I'll try the Rick G approach with a welder and spark plug rather than buy a tool I may only use once.



Last edited by 88 on Mon Oct 24, 2016 1:08 pm; edited 1 time in total


__________________________________________________
K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log1188....May contain nuts!K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

K1 - 1989 - AKA Titan (unique K1/K1100RS hybrid by Andreas Esterhammer)
K1100RS - 1995. AKA Rudolf Von Schmurf (in a million bits)
K100RS - 1991 AKA Ronnie. Cafe racer project bike
K75RTP - 1994
K75C - 1991 AKA Jim Beam. In boxes. 
K1100LT 1992 - AKA Big Red (gone)
K100LT - 1988 - AKA the Bullion brick. Should never have sold it.
    

Ringfad

Ringfad
Life time member
Life time member
Hi Will

I have a compression tester if you want to borrow it.


__________________________________________________
K1100LT with no compression on cylinder 3 - most likely cause ? Ir-log10

   ;BMW; K100RS Style Black 1987 105K Km     ;BMW; K1 Black 1993 60K Km     ;BMW;  K1100RS Black 1996       ;BMW; K1 Blue 1990 25K Miles
    

klompy the grey brick

klompy the grey brick
VIP
VIP
[quote="RicK G"]
88 wrote:
RicK G wrote:


How is the compressed air best fed into the Cylinder Rick G? I'd like to have a go before stripping the head.
I made a compressed air adapter from a busted spark plug by breaking the porcelain out and welding an air fitting to it.

I did the same and if you can rotate the crankshaft and the noise of air escaping does not stop you have a mechanical problem such as valve burnt out , hole in piston,

I always hope that the exhaust/inlet valve adjustment is way off...and fixable.

good luck


__________________________________________________
KKlompy K1100LT with no compression on cylinder 3 - most likely cause ? 2854237993
"Grace" 1984 K100RS Silver VIN 0019026 Mitt eine Staintune Zorst.
"Olivia" 1997 K1100LT Dark Grey VIN WB1052600W0237453.









Chassis number0019026
Vehicle code0503
SeriesK589
ModelK 100 RS 83 (0502 ( 0503 )
Body typeK 100 RS 83 (0502
Catalog modelECE
Production date1984 / 07
Engine0513)

K1100LT with no compression on cylinder 3 - most likely cause ? Au-log10


    

20Back to top Go down   K1100LT with no compression on cylinder 3 - most likely cause ? Empty $ave your $$ Sat Oct 22, 2016 11:18 am

Bumblebee

Bumblebee
Silver member
Silver member
Just remove the valve cover, you'll most likely find your issue there.  Since the engine runs we know it's not an intake valve, Check them out from there, you'll find it.
If you have a holey piston the engine would be belching tons of smoke.

If I were a betting man I'll guess you either have a blown out head gasket or burned valve or broken spring.

Hows the coolant level look?  If it's low or gone this would indicate a head gasket.

Have fun.

http://Bugsmashers.org/phpbb
    

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