BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   1985 4L Gas Warning Light comes on Empty 1985 4L Gas Warning Light comes on on Sun May 25, 2014 11:12 pm

BadjerJim

BadjerJim
Silver member
Silver member
1985 K100 RT.  Early model.

I have both the 7L (yellow) and 4L (red) warning lights on my speedo cluster, and all has been fine until today.

Now the 4L warning light comes on intermittently (and there's more than 4L in the tank, the yellow 7L is not even on yet).

I've read through posts here trying to find the solution, and can't find it.  There are references to this problem on early K100s.  Where should I start looking?  What would cause that darned 4L red warning light to come on when there's plenty of fuel?

Thanks!

    

2Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Sun May 25, 2014 11:29 pm

RicK G

RicK G
VIP
VIP
The system uses a thermistor for each level and when the fuel is in contact with the thermistor it is cool and doesn't conduct and when the fuel drops to the level it is exposed so warms up and conducts bringing the light on.
Being that the light comes on when there is fuel to cool it I would say the thermistor could well be cactus.
You would need to get someone who is conversant with that side of electronics to test it.
You may find a good used sender but I would not be too hopeful as I dont think I have ever seen one for sale.
It might be easiest to just disconnect the light and use the tried and proven open the cap and check like I do regard less of what my light or gauge tells me.


__________________________________________________
"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 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

3Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 1:13 am

Jhepburn

Jhepburn
Silver member
Silver member
I can't help you with the problem, but if you do need to replace the thermistor - good luck! I managed to buy a second-hand unit when mine fractured at the base and started leaking petrol - there are some on eBay, but rarely and of questionable quality. I think I got lucky with mine. The design of the early ones means you can't just replace one component - it's all or nothing.

Unless you're lucky, I think you'll be safer just going on manual checks and the trip meter.

    

4Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 1:55 am

k-wopper

k-wopper
Silver member
Silver member
1985 4L Gas Warning Light comes on Img_1523
Hi guys, This is a subject that has been dear to my heart the past couple of days. Mine not only doesn't works but it leaks!
I am new to posting pictures so please be kind.
the first picture is of the sender unit which is screwed into the underside of the tank
Having trouble with other pics so will try to get the important one even if is in another post

    

5Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 2:13 am

k-wopper

k-wopper
Silver member
Silver member
Part deux!!!!
1985 4L Gas Warning Light comes on Img_1526 drunken 
OK, slightly better but I am trying.
There are 5 wires coming via the 4 prong the 2 long ones are the fuel pump power. note the stake on eyelets are different sizes. one is 8mm
the other is 7mm this is very thoughtful of BMW but I would have preferred not to have to figure this out myself.
the other 3 wires consist a short brown wire to the lowest thermistor and the return wires should correspond in length. these are soldered connections and in my case one was broken.
I did not think to measure any values in the thermistors which you can see as the small cylinder type objects that resemble resistors from the outside.
In my case the inner sleeve of the base had leaked between it and the outer sleeve both which are held on to the tank by the large nut.
Right now my sensor is curing a combination of JB weld topped by a fuel resistant gasket compound. I will test it tomorrow and report on my success :cyclops: 
This entire contraption is very flimsy and breakable (un-like the rest of the bike) so be careful of torque and tugging.
I hope this helps you as I could not find any direct pictures in my search.(probably the wrong places.
Cheers 
Rob

    

6Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 5:39 am

charlie99

charlie99
VIP
VIP
good work rob ...hope it comes good for you

cheers


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O1985 4L Gas Warning Light comes on Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

7Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 10:19 pm

orforester

orforester
Silver member
Silver member
and keeping in the same vein as this thread, how the heck do you keep the plug from falling out the bottom of this sensor? 

Seems like it plugs in, but the slightest touch would make it fall out.


__________________________________________________
89 K 100 RS se
85 K 100 RT
    

8Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Mon May 26, 2014 10:38 pm

kartooo

kartooo
Silver member
Silver member
@orforester wrote:and keeping in the same vein as this thread, how the heck do you keep the plug from falling out the bottom of this sensor? 

Seems like it plugs in, but the slightest touch would make it fall out.

when i bought mine the previous owner had an on/off fuel pump problem.
i found that fuel pump/fuel level sensor plug had a very loose fit.
i gently squeezed up the 4 female connectors with a pick to snug them up.
been ok for the past 3k miles.


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

9Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Fri May 30, 2014 9:20 pm

orforester

orforester
Silver member
Silver member
So you opened them up a little with a pick??  like made the Male plugs wider??


__________________________________________________
89 K 100 RS se
85 K 100 RT
    

10Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Fri May 30, 2014 10:34 pm

kartooo

kartooo
Silver member
Silver member
@orforester wrote:So you opened them up a little with a pick??  like made the Male plugs wider??

nope,squashed the female one's smaller by slipping a pick between the plastic and metal connectors.
originally it was loose enough that just gravity and slight tap would make it come off !
what i did gave it enough drag/friction to hold on snug.
i read some place that there is a spare female connector just like it in the solenoid box under the tank.
i think it was for an optional alarm.


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

11Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Fri May 30, 2014 11:22 pm

92KK 84WW Olaf

avatar
Life time member
Life time member
I had the same problem and used a small precision screwdriver to open out the male pins. It has never given trouble since.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska 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 105,200 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

12Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Sat May 31, 2014 6:24 am

Inge K.

Inge K.
VIP
VIP
@kartooo wrote: i read some place that there is a spare female connector just like it in the solenoid box under the tank.
i think it was for an optional alarm.

Correct, the same connector is used for the OEM alarm.

1985 4L Gas Warning Light comes on Alarm_10


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

13Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Sat May 31, 2014 6:58 am

bushyintas

bushyintas
Silver member
Silver member
I had the same issue with my cafe build.  replaced the plug on the cable end with one off an old C.B. radio microphone, it has the same configuration as well as a threaded knurled nut that screws over the tank gauge female fitting. It has worked now for a few years, never fallen off.

http://search.jaycar.com.au/search?w=4%20pin%20mic%20plug&view=list

http://www.ebay.com.au/itm/NEW-MICROPHONE-PLUGS-4-PIN-MIC-CB-RADIO-HAM-27mhz-MIKE-/190417511542?pt=AU_Electronics_Radio_Equipment&hash=item2c55c4a476

1985 4L Gas Warning Light comes on Untitl10

Good luck.


__________________________________________________
Bushy

k100 RT 1988 #0095723
K100 RT 1984 into Custom Single seat.  #0024503
    

14Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Sat May 31, 2014 7:11 am

Inge K.

Inge K.
VIP
VIP
1985 4L Gas Warning Light comes on 112350  smart one, bushy.


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

15Back to top Go down   1985 4L Gas Warning Light comes on Empty Re: 1985 4L Gas Warning Light comes on on Sat May 31, 2014 10:08 am

kartooo

kartooo
Silver member
Silver member
@Inge K. wrote:1985 4L Gas Warning Light comes on 112350  smart one, bushy.

+1
i am a ham and have a few of them kicking around.
got 1 next to me right now on my Ten-Tec Omin VI mic....


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum