BMW K bikes (Bricks)


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1Back to top Go down   Introduction to K1 misfire Empty Introduction to K1 misfire Tue Apr 11, 2023 5:23 pm

Nsdean03

Nsdean03
active member
active member
Hello, I have just recently purchased a 1991 K1 with 47,000 miles. I replaced the spark plugs, spark plug wires, all fluids, front fork seals, fuel filter etc... After getting the bike together and started, the bike seems to develop a missfire regardless of RPM's. It sounds as if there is some sort of "mechanical slack" (bad description) when the missfire happens. Nothing I've ever heard before on any other bike.

I'm at a loss of what it could be? I'm familiar with the airheads/oilheads but not the K bikes (first one)

Any potential ideas of what could be wrong would be greatly appreciated! Thanks!

    

2Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Tue Apr 11, 2023 6:15 pm

charlie99

charlie99
VIP
VIP
possible injector spray pattern - sticky ness issue ?

may need to get them cleaned ...


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

3Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Tue Apr 11, 2023 6:24 pm

duck

duck
Life time member
Life time member
1 - Check that the spark plug leads are all firmly seated on the spark plugs. If you're using OEM leads then they should not wiggle at all.

2 - If you have a butane/propane torch then spray some unlit gas around the boots between the throttle bodies and cylinder head. If the idle goes up then one or more of those boots is cracked and leaking.

Introduction to K1 misfire K1100r10

Regardless if that solves your problem or not, remove the ignition amp from the front left corner of the battery tray and refresh the heat sink compound. The most ignored/unknown maintenance item on these bikes. If that heat sink compound is not keeping the ignition amp cool then the bike will not run as well as it should.

Introduction to K1 misfire Img_3110


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

4Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Tue Apr 11, 2023 6:57 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
If the bike has been sitting for a long time the injectors may be varnished up.  Get a bottle of Techron Fuel System Cleaner and put some in your tank.  Run the engine for five minutes to mix and circulate it through the system.  Let the bike sit overnight and run it again for five minutes the next day.  Continue doing this while you work on other stuff on the bike.  After 4-5 days any varnish in the injectors should be cleaned out.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

5Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Tue Apr 11, 2023 7:26 pm

Nsdean03

Nsdean03
active member
active member
Thank you for the responses everyone! I will try some of your recommendations out.

    

6Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Wed Apr 12, 2023 5:48 am

Bernie_K100

Bernie_K100
Life time member
Life time member
Hi,

Introduction to K1 misfire 177912 to this forum!


Bernie

p.s.: when replacing the spark plugs, keep attention that you will use ones with "SAE-Plugs". Without this little parts it could be, that you have no correct ingition.
look also here for an example:

forum.kforum-tech.com/members-upload/uploads/Zuendkerze_mit_SAE_Mutter.doc

    

7Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Wed Apr 12, 2023 10:49 am

fishboy316

fishboy316
Life time member
Life time member
Welcome! Good luck with the K1.

    

8Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 5:12 pm

Nsdean03

Nsdean03
active member
active member
Well, no luck on it running any better. I ran the bike in the dark to see if I could see anything and noticed that you could see detonation from the top of the throttle body every time it missfired. I've never seen anything like that. So something is not causing ignition at the proper moment I suppose?

    

9Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 5:53 pm

Dai

Dai
Life time member
Life time member
What exactly do you mean by 'see detonation from the top of the throttle body'? Is there a split in the rubber?


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

10Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 6:51 pm

Laitch

Laitch
Life time member
Life time member
Nsdean03 wrote:Well, no luck on it running any better.
Which of the suggestions made here did you follow—all of them?

    

11Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 7:17 pm

Nsdean03

Nsdean03
active member
active member
I've attempted everything but checking the heat sink compound involving the ignition amp. Instead of using Techron I used Liqui-moly fuel injector cleaner.

So where the throttle body and intake tube attach, there is clamp. When running the bike, a missfire will occur. When that missfire happens you can see a flash under the clamp on the second throttle body to the left. It's hard to explain so I apologize for being confusing. There are no splits or tears in the rubber.

    

12Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 7:44 pm

charlie99

charlie99
VIP
VIP
Is this flash above or below the throttle bodies ?


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

13Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 8:18 pm

Laitch

Laitch
Life time member
Life time member
Nsdean03 wrote:I've attempted everything but checking the heat sink compound involving the ignition amp.
Cleaning the ignition amplifier and applying heat sink compound (heat paste) can be an important element in preventing misfires in the 4V models like yours; its condition should not be ignored. It is located on the battery holder. The compound is available at Napa, Pep Boys and other parts stores. BMW uses Curil K but the others get the job done. See if you can decipher these instructions from a K1/K100RS 4V manual.

Introduction to K1 misfire Igniti12

    

14Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 8:22 pm

duck

duck
Life time member
Life time member
Laitch wrote:
Nsdean03 wrote:I've attempted everything but checking the heat sink compound involving the ignition amp.
Cleaning the ignition amplifier and applying heat sink compound (heat paste) can be an important element in preventing misfires in the 4V models like yours; its condition should not be ignored. It is located on the battery holder. The compound is available at Napa, Pep Boys and other parts stores. BMW uses Curil K but the others get the job done. See if you can decipher these instructions from a K1/K100RS 4V manual.

I got mine at Radio Shack. (Before they closed most of their stores.)

I just scrape off all of the old stuff with steel wool and then apply a new coat.

Made a noticeable difference when I refreshed it on my 91 K1.

If it gets bad enough it will kill the bike after a few blocks of riding. (similar symptom to a failing HES)


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

15Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 8:31 pm

Nsdean03

Nsdean03
active member
active member
charlie99 wrote:Is this flash above or below the throttle bodies ?
Above

    

16Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Fri Apr 14, 2023 8:32 pm

Nsdean03

Nsdean03
active member
active member
duck wrote:
Laitch wrote:
Nsdean03 wrote:I've attempted everything but checking the heat sink compound involving the ignition amp.
Cleaning the ignition amplifier and applying heat sink compound (heat paste) can be an important element in preventing misfires in the 4V models like yours; its condition should not be ignored. It is located on the battery holder. The compound is available at Napa, Pep Boys and other parts stores. BMW uses Curil K but the others get the job done. See if you can decipher these instructions from a K1/K100RS 4V manual.

I got mine at Radio Shack. (Before they closed most of their stores.)

I just scrape off all of the old stuff with steel wool and then apply a new coat.

Made a noticeable difference when I refreshed it on my 91 K1.

If it gets bad enough it will kill the bike after a few blocks of riding. (similar symptom to a failing HES)
Ok I'm going to give that a try then. I'll laugh when the only thing I didn't try was the problem. Thanks again guys!

    

17Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 2:37 am

jbt

jbt
Life time member
Life time member
Misfires are more often due to malfuntion of the Hall effect sensor(s). The sensor itself or the cooked wires. Due to the age of these parts, it's very common today that they're faulty.


__________________________________________________
Let us enjoy the transient delight
That fills our fairest day.
    

18Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 8:05 am

Dai

Dai
Life time member
Life time member
You may not think the rubber is split, but I'll wager that it is. Did you try the butane trick?


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

19Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 10:30 am

Nsdean03

Nsdean03
active member
active member
Dai wrote:You may not think the rubber is split, but I'll wager that it is. Did you try the butane trick?
Yes, and no changes. Very strange

    

20Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 11:24 am

duck

duck
Life time member
Life time member
Don't forget to check the hyperspatial quasiturbo reverse deconfabulator. (Bosch stole the design from Lucas.)


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

21Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 12:21 pm

Nsdean03

Nsdean03
active member
active member
duck wrote:Don't forget to check the hyperspatial quasiturbo reverse deconfabulator. (Bosch stole the design from Lucas.)
Ah yes, I almost forgot about the hyperspatial quasiturbo reverse deconfabulator, how silly of me.

    

22Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sat Apr 15, 2023 12:30 pm

Laitch

Laitch
Life time member
Life time member
Nsdean03 wrote:Ah yes, I almost forgot about the hyperspatial quasiturbo reverse deconfabulator, how silly of me.
You won't forget it again after you've spent four hours using the Q-tips, ethanethiol, bulb syringe and emesis basin to take care of it if refreshing the heat paste doesn't work.

    

23Back to top Go down   Introduction to K1 misfire Empty Re: Introduction to K1 misfire Sun Apr 16, 2023 11:19 am

Two Wheels Better

Two Wheels Better
Moderator
Moderator
Moved to Technical Repair & Troubleshooting, from Member's Intro, because, well it should have just been a member's intro with questions asked later and in the section for such posts...but you know how the bar room sometimes gets noisy when a new drinker walks in. 
Smile


__________________________________________________
"A long ride is the answer to a question you will soon forget!" ~ Anonymous
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

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