BMW K bikes (Bricks)

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1Back to top Go down   Fuel pump  Empty Fuel pump on Sat May 25, 2019 9:22 pm

stevenh

stevenh
active member
active member
I have just brought a K100 trike conversion. With it I inherited a bad missfire that makes it unrideable. The trike has had extensive work Compression check, valve clearances, fuel rail acid dipped, new fuel pump and filter, new plugs, coils leads and caps. Anyway checking for the missfire I noticed the fuel pump was not priming. I checked the fuses and one was blown. I replaced it, the fuel pump primed up and the missfire improved considerably. But not for long, now the fuel pump is not priming but the fuses are ok. I took each one out and tested them with a multi meter. I am now wondering if it is a relay.

My electrical knowledge is limited. Does anyone have any clues to the cause of the problem. Is it a relay, and exactly where can I locate the relay. Is there any way to test it

Cheers
Steve

    

2Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sat May 25, 2019 10:12 pm

MartinW

MartinW
Life time member
Life time member
The four pin connector that resides under the RH side of the tank is a known source of problems. Cleaning with Deoxit can sometimes remedy the problem. Alternatively replacing the whole connector with a good waterproof one will fix it. You can also pull the pump and bench test it. I am currently running a Chinese copy pump which has so far proved reliable. Seehttp://www.motobrick.com/index.php/board,8.0.html
Regards Martin.



Last edited by MartinW on Sat May 25, 2019 10:13 pm; edited 1 time in total (Reason for editing : Bad link)


__________________________________________________
K75s Hybrid
    

3Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sat May 25, 2019 10:16 pm

Basic2

Basic2
Platinum member
Platinum member
Another thing is to check the through connector in the bottom of the tank which feeds 12V from the bike into the fuel pump in the tank. Mine had gone high resistance, stopping the pump from working.


__________________________________________________
K100 Basic 2
11/1987 6308319K100CJ
Marakesh Red
    

4Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sun May 26, 2019 2:52 am

stevenh

stevenh
active member
active member
@MartinW wrote:The four pin connector that resides under the RH side of the tank is a known source of problems. Cleaning with Deoxit can sometimes remedy the problem. Alternatively replacing the whole connector with a good waterproof one will fix it. You can also pull the pump and bench test it. I am currently running a Chinese copy pump which has so far proved reliable. Seehttp://www.motobrick.com/index.php/board,8.0.html
Regards Martin.
Thanks Martin, the plugs looks like it has been replaced with a Strip / block connector. I will get a new plug so I can rule that out completely.

Cheers
Steve

    

5Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sun May 26, 2019 2:55 am

stevenh

stevenh
active member
active member
@Basic2 wrote:Another thing is to check the through connector in the bottom of the tank which feeds 12V from the bike into the fuel pump in the tank. Mine had gone high resistance, stopping the pump from working.

Thanks mate I have the tank off now so I will check it out. How exactly can I check if it is as you say ' High resistance'

Cheers
Steve

    

6Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sun May 26, 2019 5:47 am

Basic2

Basic2
Platinum member
Platinum member
Take the pump out of the tank and use a multimeter to check the continuity of the wires between the 4 pin plug and the terminals on the pump. On mine the positive feed to the pump had gone high resistance, and would vary between several megaohms when you moved the wires near the through connector.


__________________________________________________
K100 Basic 2
11/1987 6308319K100CJ
Marakesh Red
    

7Back to top Go down   Fuel pump  Empty Re: Fuel pump on Sun May 26, 2019 5:53 am

stevenh

stevenh
active member
active member
@Basic2 wrote:Take the pump out of the tank and use a multimeter to check the continuity of the wires between the 4 pin plug and the terminals on the pump. On mine the positive feed to the pump had gone high resistance, and would vary between several megaohms when you moved the wires near the through connector.
Sweet thanks for that, I have the tank off now, I'll take a look, it's going to be a couple of days before I can look at it again though due to work commitments.

Steve

    

8Back to top Go down   Fuel pump  Empty Re: Fuel pump on Mon May 27, 2019 12:10 am

volador

volador
active member
active member
Cool trike

The 4 pin configuration on the male end of the Petrol Gauge Level Sender

1.Brown-is ground continuity to the larger diameter ring terminal

2.Green-is 12V continuity to the smaller diameter ring terminal

3.Yellow-is fuel level

4.White-is 4 litre reserve indicator

Remove the ring terminals from the fuel pump to perform the continuity test for #1,2



Last edited by volador on Tue May 28, 2019 4:28 pm; edited 1 time in total


__________________________________________________
1984 K100RS 1991 K100RS
    

9Back to top Go down   Fuel pump  Empty Re: Fuel pump on Mon May 27, 2019 7:36 am

stevenh

stevenh
active member
active member
@volador wrote:Cool trike

The 4 pin configuration on the male end of the Petrol Gauge Level Sender

1.Brown-is ground continuity to the larger diameter ring terminal

2.Green-is 12V continuity to the smaller diameter ring terminal

3.Yellow-is fuel level

4.White-is 4 litre reserve indicator

Remove the ring terminals from the fuel pump to perform the continuity test for #1,2
Thanks volador, Yes the trike is interesting, I haven't had a decent ride since I picked it up a couple of weeks ago due to the missfire. I have seen another in New Zealand based on the naked K75. Both Mine and the K75 were built by ' Trikeworks ' a well known trike builder here in NZ.

The colour coding is very helpful thanks

Steve

    

10Back to top Go down   Fuel pump  Empty Re: Fuel pump on Mon May 27, 2019 8:11 am

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
@stevenh wrote:I have just brought a K100 trike conversion. With it I inherited a bad missfire that makes it unrideable. The trike has had extensive work Compression check, valve clearances, fuel rail acid dipped, new fuel pump and filter, new plugs, coils leads and caps. Anyway checking for the missfire I noticed the fuel pump was not priming. I checked the fuses and one was blown. I replaced it, the fuel pump primed up and the missfire improved considerably. But not for long, now the fuel pump is not priming but the fuses are ok. I took each one out and tested them with a multi meter. I am now wondering if it is a relay.

My electrical knowledge is limited. Does anyone have any clues to the cause of the problem. Is it a relay, and exactly where can I locate the relay. Is there any way to test it

Cheers
Steve

The photo you have up shows RT/LT fairing.

These were all 2V engines and the fuel pumps on these do NOT prime. They only get power when you press the start button. Nothing happens when you switch on the ignition. On 16v engines you will hear the pump as soon as you switch on ignition and bring kill switch to on position.

To check the relay swap the horn and fuel pump relays and see what happens. They are the same and will swap. All in the box under the fuel tank. These ones are not screwed in or bolted in, just pull them out.

Another point you haven't mentioned is the big plug into the Fuel Injection Control Unit under the seat, a known dodgy point and worth checking pins are clean and the plug is correctly seated.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now91,850 miles
1983 K100RS 0011175 Fricka 29,495 miles Damn K Pox
    

11Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue May 28, 2019 6:11 am

stevenh

stevenh
active member
active member
@92KK 84WW Olaf wrote:
@stevenh wrote:I have just brought a K100 trike conversion. With it I inherited a bad missfire that makes it unrideable. The trike has had extensive work Compression check, valve clearances, fuel rail acid dipped, new fuel pump and filter, new plugs, coils leads and caps. Anyway checking for the missfire I noticed the fuel pump was not priming. I checked the fuses and one was blown. I replaced it, the fuel pump primed up and the missfire improved considerably. But not for long, now the fuel pump is not priming but the fuses are ok. I took each one out and tested them with a multi meter. I am now wondering if it is a relay.

My electrical knowledge is limited. Does anyone have any clues to the cause of the problem. Is it a relay, and exactly where can I locate the relay. Is there any way to test it

Cheers
Steve

The photo you have up shows RT/LT fairing.

These were all 2V engines and the fuel pumps on these do NOT prime. They only get power when you press the start button. Nothing happens when you switch on the ignition. On 16v engines you will hear the pump as soon as you switch on ignition and bring kill switch to on position.

To check the relay swap the horn and fuel pump relays and see what happens. They are the same and will swap. All in the box under the fuel tank. These ones are not screwed in or bolted in, just pull them out.

Another point you haven't mentioned is the big plug into the Fuel Injection Control Unit under the seat, a known dodgy point and worth checking pins are clean and the plug is correctly seated.
Thanks Olaf. you are correct it is an LT. Are you sure about the fuel pump not priming. I replaced a blown fuse and was sure I heard the pump priming once the fuse was replaced ( in saying that it is not priming now).

I will check the control unit, and relays. Thanks for the info

Steve

    

12Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue May 28, 2019 6:26 am

Basic2

Basic2
Platinum member
Platinum member
When you turn the key to "on", the pump doesn't operate until the start button is pressed. If the motor doesn't start the pump will run for a couple of seconds after the starter button has been released and the starter has stopped.


__________________________________________________
K100 Basic 2
11/1987 6308319K100CJ
Marakesh Red
    

13Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue May 28, 2019 6:33 am

stevenh

stevenh
active member
active member
@Basic2 wrote:When you turn the key to "on", the pump doesn't operate until the start button is pressed. If the motor doesn't start the pump will run for a couple of seconds after the starter button has been released and the starter has stopped.
Right so that might be a good way to test if my pump is working then. Maybe a quick jab on the start button and see if I can hear the pump. If so could I assume my wiring and connections are all good. ?

    

14Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue May 28, 2019 7:28 am

92KK 84WW Olaf

92KK 84WW Olaf
Life time member
Life time member
Another little test I have used.

If you press the start button and the engine actually fires at that point, keep the start button pressed and if this keeps the engine firing it means your fuel pump is getting power and the fuel circuits relay etcshould beok.

If it cuts out then after you release the start button then you have a different focus. At this point the system is now relying on the signal from the Hall Effect Sensors [HES] under the T cover at the front of the engine. Most common issue may be the connections and this eventually goes through the Fuel Injection Control Unit [FICU]under the seat which is a common area to get some issues mostly related to poor electrical contact or the plug not seated correctly. On your 2v at the front of the petrol tank is another unit, under the headstock, Ignition Control Unit [ICU]. This also has a plug connector that may need some cleaning. It has two nuts and it slides backwards to come out, in case you are wondering how on earth do you get this thing out.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 58,645 now91,850 miles
1983 K100RS 0011175 Fricka 29,495 miles Damn K Pox
    

15Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue May 28, 2019 8:28 am

GF Wollongong

GF Wollongong
Silver member
Silver member
As an owner of the earlier 2 valve...

the standard move for me is to half press the starter button at least once to prime the fuel line - the pump will be heard.

Bike will / seems to start easier with the priming

You stated earlier: "I replaced a blown fuse and was sure I heard the pump priming once the fuse was replaced"

This will happen if the starter button is pressed too hard and is stuck in (the shaft under the green button is metal... and creates a circuit across two pins... and can get trapped between them). Mine does this occasionally. Just pull it back out.


Stupidly, I hadn't noticed mine did this the last time I rode it. So I thought that the starter relay was welded closed...Up with the tank, out with the relay, failed to open it, in with a replacement...same problem! Then I noticed the starter button stuck in.


Had a good ride after that.

G

    

16Back to top Go down   Fuel pump  Empty Thanks everyone on Wed May 29, 2019 7:21 am

stevenh

stevenh
active member
active member
Thanks everyone for all the feedback on my missfire problem. Fuel pump  112350I have plenty of good info and a 3 day weekend coming up. I plan to go over pretty much everything mentioned here. Hopefully I'll end up wit a good result

Cheers
Steve

    

17Back to top Go down   Fuel pump  Empty Re: Fuel pump on Wed May 29, 2019 7:21 pm

Woodie

Woodie
Life time member
Life time member
"the standard move for me is to half press the starter button at least once to prime the fuel line"


Fuel pump  212902 What GF said


__________________________________________________
1985 K100RT
52667
"Keep your stick on the ice. We're all in this together." Red Green
    

18Back to top Go down   Fuel pump  Empty Correct Fuel pump replacement kit on Tue Jun 04, 2019 5:00 am

stevenh

stevenh
active member
active member
Well over the weekend I took my tank off and went through all the electrical connections on good advice from many people on the forum. Although the fuel system had been Refurbished new pump, fuel rail injectors. I thought I would take a quick look in the tank while it was empty.

I was horrified at what I found. The fuel pump looked like a generic car fuel pump, just sitting loosley in the bottom of the tank. no anti vibration mount, no fuel filter, the fuel strainer had become detached, the original hoses replaced with thin hose. The wiring to the pump was crap.

I have decided to pull it all out, and buy an aftermarket kit from the U.S.

Can anyone tell me the correct kit for my 1987 K100 LT. With the return hose or without the return hose. I believe it is the kit without the return but I'm not sure

Here are a couple of pics, seeing is believing

https://www.pinterest.nz/pin/566398090635958990/

https://www.pinterest.nz/pin/566398090635958987/

https://www.pinterest.nz/pin/566398090635958965/

Cheers
Steve

    

19Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue Jun 04, 2019 6:13 am

Basic2

Basic2
Platinum member
Platinum member
Hi Steve,
My 11/87 K100 CJ had a 43mm diameter pump mounted in the vibration damper, and a sock filter. The OEM 12V feed to the pump uses ring connectors, not spade connectors.


__________________________________________________
K100 Basic 2
11/1987 6308319K100CJ
Marakesh Red
    

20Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue Jun 04, 2019 7:30 am

GF Wollongong

GF Wollongong
Silver member
Silver member
I would suggest that (inside your tank) is not an uncommon sight. The rust and general mank should be remedied by 10 X 2 litre bottles of white vinegar ... Aldi $1.19 each (if I remember). Soak for several days and plastic scourer should clean it up.

Neglected bikes frequently suffer from vibration damper decay... The plastic mount is usually okay but the rubber often presents in a tar like state due to old fuel and ethanol usage. Plastic mounts can be obtained easily - it's just the cost of the damper that forces skin flints (like me) to try alternatives.

Is the pump working? If not, I have twice run into "jammed impellers" in the bottom of the fuel pump. Solution is to remove it, pinch the aluminium outer housing crimps flat and slide the inner out (may take some persuasion ... like a hammer handle and rubber mallet...handle against the bottom of the pump and light tap with something heavy (the mallet) will gradually work it up and out. Not sure if I used soft jaws in the vice).

Then in the bottom of the pump you will find several roller bearing impellers (used to pull the fuel through the pump). One might well be jammed, can be freed and pump is put back together and works fine.

I have wedged fuel line between the plastic mount and the pump. Just cut a slot into the side of the short length of fuel line to key into the lip on the inside of the plastic mount. Took three lengths of approx 100 mm. Temp solution only.

good luck

Guy

    

21Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue Jun 04, 2019 9:37 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
If I'm not mistaken, some of the inmates here have successfully run their bricks with inexpensive(cheap doesn't sound good in reference to an important part like a fuel pump) ChiCom fuel pumps. I believe Martin is one of them, and he may soon add some further information.

I myself, have one of these $15 pumps in the top case of my touring bike. I carry it on the theory that it prevents the pump in the tank from failing. So far, it has performed perfectly in over 40,000 miles of riding.


__________________________________________________
Present:
1994 K75RT
1991 K100RS

Past:
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
    

22Back to top Go down   Fuel pump  Empty Re: Fuel pump on Tue Jun 04, 2019 9:55 am

yamaguzzi

yamaguzzi
Gold member
Gold member
I found all sorts of crap in my tank when I first got my bike with only 12000 miles on it.She hadn't been run for almost 15 years and everything in there rusted.I pulled it all out,washed the inside of the tank with heavy duty floor washing detergent then put in some muriatic acid .In 3 seconds the inside of the tank shined like new ! Then I washed it out again with detergent and rinsed a few times with water and I had a like new tank.Don't get the acid on the paint and wear protection on your eyes and your hands and wear a good respirator! PROTECTION IS IMPORTANT ! I then bought the middle of the road (price wise) stuff from https://www.euromotoelectrics.com/category-s/1639.htm and for just about 300 dollars totally rebuilt my fuel delivery system from the gas tank down to the injectors with the exception of the actual injectors which I cleaned and are fine. All new hoses , clamps,pressure regulator pump filter,submersible lines and so on. Start fresh like this and it will be a real reliable bike for a real long time


__________________________________________________
1988 K 100RS ,1975 Moto Guzzi 850-T , 1971 BMW R60/5 , 1971 Yamaha R5B,1969 Yamaha DS6C ,1966 Yamaha YM1 , 1965 Yamaha YDS3
https://motoguzzi850t.blogspot.com/
    

23Back to top Go down   Fuel pump  Empty Fuel pump kit on Wed Jun 12, 2019 7:03 pm

stevenh

stevenh
active member
active member
I have just ordered a full aftermarket in tank fuel pump kit for the trike. When this is installed, can I just pull out the injectors on the rail and check if they are clear by turning the engine over. I am hoping any blockages will be obvious.

    

24Back to top Go down   Fuel pump  Empty Re: Fuel pump on Wed Jun 12, 2019 7:29 pm

MartinW

MartinW
Life time member
Life time member
My $37.00 Au Aliexpress pump has been whirling away without missing a beat for nearly 2 years. I ran it as a experiment while keeping my OEM cleaned and preserved in the tail as a backup. I did as much research as possible and went with a manufacturer. http://www.motobrick.com/index.php/topic,10054.msg86054.html#msg86054
Some Chinese parts are probably not up to scratch, but some are, and they are improving. You'd be surprised how many car and bike parts are actually made in China.I'm currently running a Chinese rear master cylinder $13.00 Au a Chinese motorcycle GPS $100.00 Au and a Chinese twin port USB handle bar mount $5.00 Au. The only problems encountered have been the GPS power supply ( No backup) and that the map updates are dearer than buying a whole new GPS. I did have trouble with a temperature sensor but it was for the later K100 so I gave it to a mate.
Regards Martin.


__________________________________________________
K75s Hybrid
    

25Back to top Go down   Fuel pump  Empty Re: Fuel pump on Thu Jun 13, 2019 12:59 am

Laitch

Laitch
Life time member
Life time member
@stevenh wrote:When this is installed, can I just pull out the injectors on the rail and check if they are clear by turning the engine over.
You could do that, or you could just try starting the engine to determine how well it runs. If you test the injectors on the rail by activating the starter, be aware that could become a method of igniting the moto by accidental misdirection of fuel spray.


__________________________________________________
1995 K75T 68,000 miles
Fuel pump  Usa-lo10
    

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