BMW K bikes (Bricks)

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1Back to top Go down   K75C Wont start Empty K75C Wont start Sun Jun 26, 2022 1:20 am

Rockman

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This is for a 1987 K75C. It was running perfectly up until yesterday. Now it wont start. I can hear the fuel pump when I stop cranking the motor, but its all silent when I first turn the ignition on. I did check the connector for the computer and all seems ok there. I also checked the sidestand switch connection while I was there, but if this were a problem it wouldnt crank. I did check the fuses. At this stage I havent really had time to check for spark or injectors etc. Any suggestions welcome?

    

2Back to top Go down   K75C Wont start Empty Re: K75C Wont start Sun Jun 26, 2022 1:53 am

MartinW

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Check to see if the plugs are wet or dry.
Regards Martin.


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K75s Hybrid
    

3Back to top Go down   K75C Wont start Empty Re: K75C Wont start Sun Jun 26, 2022 8:28 am

Laitch

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Rockman wrote:This is for a 1987 K75C. It was running perfectly up until yesterday. Now it wont start. I can hear the fuel pump when I stop cranking the motor, but its all silent when I first turn the ignition on.
So far, things seem normal with your moto. The fuel pump starts when the engine is cranked, not when the ignition switch is turned to On. When the engine stops cranking, the pump runs for a second or two.


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1995 K75 81,000 miles
K75C Wont start Usa-lo10
    

4Back to top Go down   K75C Wont start Empty Re: K75C Wont start Sun Jun 26, 2022 9:23 am

Arlina

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It's a 2V, wich doesn't have a sidestand switch.

Try pull the clutch and start the bike.


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K75C Wont start Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

5Back to top Go down   K75C Wont start Empty Re: K75C Wont start Wed Jun 29, 2022 1:33 am

Rockman

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I cranked it and got a little hit, then a bit more and so on. A bit of smoke but not excessive. It now runs like it should. All I can put it down to at the moment is fouled plugs. I have no idea how old they are so I'll put a new set in and see what happens.

    

6Back to top Go down   K75C Wont start Empty Re: K75C Wont start Wed Jun 29, 2022 2:20 am

MartinW

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Some times K75s can flood possibly caused by a bad connection to the temp sensor. Until it has a chance to dry out starting can be harder to achieve. Very occasionally at other times when it won't start mine a bit of throttle is needed.
Regards Martin


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K75s Hybrid
    

7Back to top Go down   K75C Wont start Empty Re: K75C Wont start Wed Jun 29, 2022 7:27 am

Point-Seven-five

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One of the shortcomings of the fuel injection on the bricks is that it will keep pumping fuel into a flooded engine.  It's realy important that you never twist the throttle when starting, just use the "choke" lever. 

When it does fail to start and you can smell gas at the exhaust or see wet plugs, I will unplug the tank connector and crank the engine with no fuel pump running.  After about 15 seconds of cranking the engine will blow out the excess fuel to where it can fire.  Then plug in the tank and the engine should start normally.


__________________________________________________
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
    

8Back to top Go down   K75C Wont start Empty Re: K75C Wont start Tue Jul 12, 2022 2:43 am

Rockman

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Point-Seven-five wrote:One of the shortcomings of the fuel injection on the bricks is that it will keep pumping fuel into a flooded engine.  It's realy important that you never twist the throttle when starting, just use the "choke" lever. 

When it does fail to start and you can smell gas at the exhaust or see wet plugs, I will unplug the tank connector and crank the engine with no fuel pump running.  After about 15 seconds of cranking the engine will blow out the excess fuel to where it can fire.  Then plug in the tank and the engine should start normally.
I know about not touching the throttle to start it. This is about my 11th K bike (5 K100's, 3 K75's, 2 K1100's and a K1200) and the first one I've had trouble with a flooded engine. Put new plugs in it today so I'll see if that makes any difference.

    

9Back to top Go down   K75C Wont start Empty Re: K75C Wont start Tue Jul 12, 2022 8:17 pm

Laitch

Laitch
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Rockman wrote:It now runs like it should. 
Are you installing new plugs to prevent stalling, or did the engine resume not running like it should?


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1995 K75 81,000 miles
K75C Wont start Usa-lo10
    

10Back to top Go down   K75C Wont start Empty Re: K75C Wont start Wed Jul 13, 2022 1:36 am

Rockman

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Laitch wrote:
Rockman wrote:It now runs like it should. 
Are you installing new plugs to prevent stalling, or did the engine resume not running like it should?
Stalling was never a problem. It just wouldnt start sometimes. Today it started no problems with the temperature hovering around zero and I took it on a 150 km run. All seems normal. Time will tell if the problem is fixed or not.

    

11Back to top Go down   K75C Wont start Empty Re: K75C Wont start Tue Aug 09, 2022 2:00 am

Rockman

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The problem seems more or less fixed. Its a little cranky to start sometimes but mostly good. Runs very well once going.

I'm wondering if there was a very small piece of something in the fuel system that got caught in one of the injectors stopping it from closing off completely. This might lead to a little fuel dribbling into a cylinder causing flooding - maybe.

I know the previous owner changed the fuel pump. Perhaps I should check that it has the correct submersible fuel hose as the wrong stuff might break down.

    

12Back to top Go down   K75C Wont start Empty Re: K75C Wont start Tue Aug 09, 2022 12:19 pm

92KK 84WW Olaf

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Rockman wrote:The problem seems more or less fixed. Its a little cranky to start sometimes but mostly good. Runs very well once going.

I'm wondering if there was a very small piece of something in the fuel system that got caught in one of the injectors stopping it from closing off completely. This might lead to a little fuel dribbling into a cylinder causing flooding - maybe.

I know the previous owner changed the fuel pump. Perhaps I should check that it has the correct submersible fuel hose as the wrong stuff might break down.
I had that on my 83 RS and in March replaced everything inside the tank. Pump, mount, damper, basket, filter, hoses, clamps. Since then I have changed the tank, outside fuel lines, clamps and all the vacuum lines and vacuum caps. I have spare clean injectors in the shed and these are going in at some later time.

My 84 RT is getting the same treatment next. I have it 9 years and last did the tank and fuel line change in 2013. 50k miles on it since.


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 49,840 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

13Back to top Go down   K75C Wont start Empty Re: K75C Wont start Mon Aug 22, 2022 7:07 pm

K75cster

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The Injectors might need a clean out or the plug caps might need a clean up.


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Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

14Back to top Go down   K75C Wont start Empty Re: K75C Wont start Mon Aug 22, 2022 7:26 pm

Rockman

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K75cster wrote:The Injectors might need a clean out or the plug caps might need a clean up.

All good now, starts first touch of the button and doesnt miss a beat. I'm guessing that whatever was causing the injectors to leak has passed through by now.

    

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