BMW K bikes (Bricks)

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diversity48

diversity48
active member
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any suggestions? 1985 k100rs...stop for a water at the local gas station after riding fairly hard for the last 4-5 hours. after filling with gas, let the bike sit on the sidestand for close to an hour. come back out, put the key in, and all i get is engine turning over strong, but NO START. battery spins it like crazy, but NO START. the only unusual symptom is gasoline appearing to be leaking out of the exhaust pipe, right at the junction beneath the footpeg, left side. as near as i can tell, the gasoline really is leaking from the exhaust pipe connection. after several more attempts to start it, it fires up and runs normally. after riding about another 42 miles, make another stop, again leaving it on the sidestand, and it appears to have stopped leaking. half hour later, come out and try starting it again, same thing happens: gas begins leaking from the same spot at a fairly constant drip, and the bike won't start. several more attempts, NOTHING. spins like crazy, but absolutely refuses to fire. take all the plugs out and they are wet with gas. after allowing time for them to dry, and a few spins to blow gas out of the then open spark plug holes, put one plug back in its holder and there is spark. put all the plugs back in and still no start. only unusual occurence happened just before the last gas fill. i had practically run it out of gas and in fact it was lurching pretty badly as i pulled up to the pump. i can't imagine that would have caused the problem...any suggestions from the gurus here? help me solve my dilema??

    

Stan

Stan
Life time member
Life time member
Is your fuel pump working?


__________________________________________________
1983 K100 basic vin 0003960 colour red  GONE
1987 K100RT vin 0094685 colour, orange peel, sorry, pearl..GONE
F800R black
    

nino

avatar
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Life time member
I believe you loose pressure in fuel system. Check fuel hoses for leaking, specially on the right side of fuel rail between rail and pressure regulator. Try to tight hose clamp on rail.

Regards

    

Jhepburn

Jhepburn
Silver member
Silver member
Wet plugs and gasoline in the exhaust suggest too much fuel getting through, and fuel leaking into the cylinders. You ran out early, so petrol is getting out when it shouldn't, and if a few attempts to start it succeeded, that sounds like clearing out an overly-rich excess.

How's your nose? Go around sniffing everywhere and see if you can find any other gasoline smells. There shouldn't be any smell except for right above the filler cap, and not even then unless it's a hot day. Check all the hose clamps, it's a good regular maintenance item anyway.

Maybe check your injectors and connections? Get them cleaned and checked professionally, or at the very least pull them out, check them, clean them as well as you can.

    

RicK G

RicK G
admin
admin
It's quite possible that one or more injectors are open all the time. Take the fuel rail off and leave the injectors still attached to the rail then turn the key on and touch the starter button and you may see fuel comming out of the injectors if I am right.
It certainly sounds like far too much fuel getting through.


__________________________________________________
"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 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

rosskko

rosskko
VIP
VIP
And see previous posts about the importance of a handy fire extinguisher


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

charlie99

charlie99
VIP
VIP
sounds verry odd to me ...

perhaps undo the under seat brain and reconnect it ...which controls the injection but could be just as simple as a corroded hall sensor cable going to the under tank brain ...but certainly sounds like something is causing all or some of the injectors to stay open .

the positive going to the injectors is always live and the ground side acts as the switch ... could something be shorting out somewhere ?.


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Osudden death for my k100...or is it just sleeping? 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 ..
    

Adiwan Djohanli

Adiwan Djohanli
Silver member
Silver member
Sounds that the fuel supply is the problem. You can start by checking your fuel pump, all fuel hoses (inlet to injector rail and fuel return hose), then the injectors as suggested in the above posting.

Cheers.


__________________________________________________
Adiwan Djohanli
Jakarta-Indonesia[i]
    

club_c

club_c
Life time member
Life time member
Sounds like way overfueling to me. FPR? Doesn't the vane in the airbox also control some of that?


__________________________________________________
"There's never enough time to do it right, but there's always time to do it over."

1988 K100RS SE VIN 01477554
    

charlie99

charlie99
VIP
VIP
fpr sounds a really good place to start ....


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Osudden death for my k100...or is it just sleeping? 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 ..
    

club_c

club_c
Life time member
Life time member
If it is overfueling to the point that fuel is dripping out the exhaust the fuel may also be finding its way past the rings into the sump. Check your engine oil level. If it looks high that's a sure sign. Then you need to immediately change your oil and filter.


__________________________________________________
"There's never enough time to do it right, but there's always time to do it over."

1988 K100RS SE VIN 01477554
    

Crazy Frog

Crazy Frog
admin
admin
@club_c wrote:If it is overfueling to the point that fuel is dripping out the exhaust the fuel may also be finding its way past the rings into the sump. Check your engine oil level. If it looks high that's a sure sign. Then you need to immediately change your oil and filter.

Very very good point about checking the oil level Club_c.
The FRP may be the culprit. Remember, the fuel pump push the pressure at 60psi+ and the FRP drop it down to 36psi.
Since the quantity of fuel injected is a relation between the pressure and the time that the injectors open, you may get twice the amount of fuel, but only a normal quantity of air. The result will be a very rich mixture flooding the engine.

Unless the ignition doesn't work or you lost compression, I would definitively check the FRP.

CF


__________________________________________________
sudden death for my k100...or is it just sleeping? Frog15sudden death for my k100...or is it just sleeping? Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

krambo

krambo
Life time member
Life time member
@Crazy Frog wrote:
@club_c wrote:If it is overfueling to the point that fuel is dripping out the exhaust the fuel may also be finding its way past the rings into the sump. Check your engine oil level. If it looks high that's a sure sign. Then you need to immediately change your oil and filter.

Very very good point about checking the oil level Club_c.
The FRP may be the culprit. Remember, the fuel pump push the pressure at 60psi+ and the FRP drop it down to 36psi.
Since the quantity of fuel injected is a relation between the pressure and the time that the injectors open, you may get twice the amount of fuel, but only a normal quantity of air. The result will be a very rich mixture flooding the engine.

Unless the ignition doesn't work or you lost compression, I would definitively check the FRP.

CF

Or even the FPR (Fuel Pressure Regulator), ask me how I know - maybe Bert's bikes have a component that mine don't - lol Wink


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." sudden death for my k100...or is it just sleeping? Uk-bmw12
http://www.its-personal.net
    

Crazy Frog

Crazy Frog
admin
admin
@krambo wrote:

Or even the FPR (Fuel Pressure Regulator), ask me how I know - maybe Bert's bikes have a component that mine don't - lol Wink

Yes a bit overworked lately Very Happy


__________________________________________________
sudden death for my k100...or is it just sleeping? Frog15sudden death for my k100...or is it just sleeping? Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

krambo

krambo
Life time member
Life time member
@Crazy Frog wrote:
@krambo wrote:

Or even the FPR (Fuel Pressure Regulator), ask me how I know - maybe Bert's bikes have a component that mine don't - lol Wink

Yes a bit overworked lately Very Happy

J/K Bert Wink


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam." sudden death for my k100...or is it just sleeping? Uk-bmw12
http://www.its-personal.net
    

diversity48

diversity48
active member
active member
i have it apart now and have found a few possible culprits. one of the pins in the connection to the fuel pump relay beneath the seat had become "dislodged" from the holder. i reconnected that, reassembled it, but still had the gas drip from the exhaust. a friend had made the suggestion to drain the oil/filter already, so i will be doing that before running it hard. the little black rubber covers on the fuel rail were cracked and brittle (2 of the 3) and i replaced those. the hoses (maybe it's just one hose?) at the ends of the fuel rail were also in poor condition (cracked at the ends). i bought some generic fuel/vac hose at the auto zone and plan on replacing those (or it) too after removing the airbox...which i haven't done yet. these hoses appear to go beneath the airbox but i'm not sure. my work schedule is a bit demanding and i won't dismantle the rest of it til tuesday (election day), as that is my next day off. after the teardown, i may find other hoses/connections that appear marginal and if so will be replacing those too.

i REALLY appreciate all the good comments and suggestions...hope something works! is there something i could have done to it by running it so low on gas? it wasn't completely out but was missing and chugging as i pulled up to the pump. possibly a check valve in the fuel tank? or, could that have caused a failure of the fuel pressure regulator...or something else? seems that i read somewhere that it's extremely important NOT to run it out of fuel, but if i DID read that, and it was for THIS bike, it did not elaborate on the possible consequences. unfortunately, some of the fuel stops on nevada back roads are few and far between. thanks again to everyone here who took the time to comment!!

    

Jhepburn

Jhepburn
Silver member
Silver member
Remove the air-box, eh?

Oooh, won't you have fun!

It's the one bit of working on the bike that is a real female dog, apart perhaps from the clutch (which I haven't done). Be very careful with the components you remove - one of them will be the air-flow sensor in the air box, and it has delicate parts inside it. There are large-size Allen-head bolts in there that may try and crack your knuckles, and then you have to manoeuvre things out of the frame. In fact, the air-flow sensor alone took me half the time of the entire job. You have to remove the huge air hose from the end, unplug the wires and then wriggle it out of the air box, from above, being careful to not damage anything inside the deceptively sturdy metal case.

I tell you this only to forewarn you, not warn you off, you understand.

The hose from the fuel rail goes behind the inlet funnels, to the Fuel Pressure Regulator, which basically contains a sprung diaphragm. It's simple, non-serviceable and takes an amount of effort to replace that is out of all proportion to the complexity of the actual part. As other people have said, it should be letting fuel through at about 36psi, but the only real way to check it is with a pressure gauge of some sort. They can stick shut, and the pump shuts down in self-defence. Mine stuck open, and there not enough pressure in the line for fuel to get through the injectors. Hell, if you're feeling flush with cash, replacing it now could save you a painful job in the future.

The hose from the FPR then goes back to the tank.

The *second* hose to the FPR is a vacuum line to regulate fuel pressure, and people argue over whether it does any good at all. Some people remove it and plug the ends, some people leave it on but plug the hose, so it looks original. Some people leave it alone. I left it alone.

My advice: Replace ALL THE HOSES. If you're going to be back there, do it NOW. So make sure you stock up on hose clamps, because most of them will be those bloody stupid non-replaceable crimped jobs.

Read the manual first, get to know it, and enter the job with a calm and serene state of mind or, if you so choose, a couple of beers on ice.

Best of luck!

    

Inge K.

Inge K.
VIP
VIP
To get acces to change the FPR and/or its related hoses,
it`s enough to remove the bottom half of the air filter housing.


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

diversity48

diversity48
active member
active member
YES, i agree that the airbox removal is quite a project...did it last year right after i got the bike. flush with money? i own 2 bmw's, an old yamaha venture and an old goldwing. flush with money i'm not, since all of these little adventures seem to always be expensive to keep up. but, you may have a good point to replace the fpr since i'm back there anyway. can't imagine how much a bmw shop would charge to replace it, but based on their charges to replace the clutch and all the related items on my R bike, i'm sure it's plenty. i know the folks at BIKE BANDIT love me for all my continued financial support, so i may just have to make another contribution. Thanks, for the continued comments, guys!!What a Face

    

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