K11 Owners Group

[Glawseagle]

Following on from my 2 earlier threads regarding my 1998 K1100LT and the Misfires/Spluttering after buying sub standard petrol from Tesco, I have finally found the source of the problem.

After cleaning out the fuels system, putting in a new fuel filter, using Wynnes Injection Cleaner, and mainly using High Octane fuel, the bike is performing very well.


But after lots of experimenting, it transpires the misfires and spluttering now only occurs when the petrol level is low. ….. about 10 miles from the yellow reserve light coming on. (I realised this when travelling up a steep hill).

So, gents …. Help please?

Now I have identified the basis of the problem, how do I find a cure?

Is the fuel pump knackered?
Is there water/contamination under the pump?
A blockage in a pipe?

Thanks in advance.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

[Scott_Anderson]

Don't let the level get that low?

If you want the warning light to come on sooner, it is possible to adjust(carefully bend) the fuel level sending unit float rod so the lamp lights sooner.

If you fill when this starts to happen, how much are you putting in the tank.
_________________
Ride safe.



1997 K1100LT 0302488
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1995 K1100LT 0302044(R.I.P.)
1997 R1100RT ZC62149(sold)

[Glawseagle]

[Flying Duck]

[malcolmt]

Interestingly my K75S has exactly the same problem with around four liters of fuel in the tank. The fuel pump apears to be seated properly so I just fill up earlier. Its damm risky when the motor cuts when accelerating (playing) in traffic. There is no hassle when out on a run away from traffic.

My K11 can go almost to the dregs of the tank before quitting, it dosent surge, just quits when the juce runs out.
I've had 350km on a tank riding through traffic to work.

Is there a difference in the reach of the 80's fuel pumps comaired to the 90's pump ???

MalcolmT
Joburg
Souf Efrica
_________________
******************************
A Bike on the road is worth two
in the shed
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[Tim (Midland Section)]

[Flying Duck]

If it's only happening on hard acceleration or accelerating uphill for a while with a low tank then it's definitely gas rushing to the back on the tank. Basic physics. I used to ride my K100RS4V pretty hard and used to experience this with a low tank.

IIRC, one of our Norwegian members reported the same issue.

Another thing is that the fuel also cools the fuel pump so not letting the tank get too empty too often might increase fuel pump longevity. I usually fill up with about a gallon left.

If you really think it's a safety issue then I'd question what kind of situations you're putting yourself in if you have to accelerate that hard for that long to remain safe. If you're just ripping on the throttle for fun though I can totally understand that.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

[tmoons]

Just another idea, maybe it helps.
A friend has a K75.
He was having difficulties with “sputtering” when he came close to an empty tank.
He sorted some things out. But could not find it.
So he took it to the dealer, they fixed him with a new Fuel filter (he already replaced the injectors himself) and cleaned the injectors. This worked, for about 2 weeks.

The final solution was that the pump just pushed dirt THRU the filter and the injectors got clogged.
After they rinses out the tank he was all fine (still is today!)

The point is, when there is (micro)dirt in the tank, it will make its way to the injectors and it will give strange problems.

Hope it helps!

[malcolmt]

The problem of fuel starvation when the tank is low has got me thinking as to what causes he same hassle on my K75. It only happens when I pull away from standstill. The fuel pump isn’t sitting too high in its rubber mounting. This morning I looked at the pump screen and noticed something curious. The parts list shows a tube connected to the screen, mine is missing. Does anyone know the where this connects and its purpose. A curious point is should a tube actually fit on the screen, how on earth would it exit the pump area ??
One thought I have is the tube may connect to the fuel return from the injector rail, the fuel would be filtered and not need passing through the screen.

With no tube connected, as the screen becomes slightly restricted, unfiltered fuel would tend to be drawn down the connection rather than across the screen. This may cause the cutting out as fuel sloshes rearwards as I pull away on a low(ish) tank with the connection being around 25mm higher then the screen.

My K11 is due a service in a couple of thousand km, I’ll take a peep at its pump and screen as a comparison.

Malcolm(t)
Joburg, South Africa



_________________
******************************
A Bike on the road is worth two
in the shed
******************************

[Flying Duck]

It goes to the pipe coming down from the top of the tank behind the gas cap. I don't know if it's true or not but I've heard that it somehow reduces cavitation in the screen. That might be what's happening to your K75 if that tube is not hooked up.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

[malcolmt]

My fuel return from the injector rail seems to spray into the tank although I'm not certain where the outlet is ?
Could this be the pipe you refer to ?
_________________
******************************
A Bike on the road is worth two
in the shed
******************************

[Flying Duck]

[malcolmt]

Hey Drake, maybe I beat you to it.
I've just peeked in the K75 tank and found a tube connected to a pipe just in front of the filler, the other end was dangling in fresh air.

It was a PITA but I got it connected both ends.
We'll see if it makes a difference next week when I'm playing in the traffic.

Cheers
Malcolm(t)
_________________
******************************
A Bike on the road is worth two
in the shed
******************************

[Glawseagle]

This is just the best forum for all BMW info.

Thanks for all the input.

I have now travelled around 250 miles since the last bout of mis-firing spluttering ...... and I have filled up each time before the yellow light comes on.

I do think Wynn's Injector Cleaner has helped!

So, I have found a way around the issue .....

I will now run the petrol down until the yellow light comes on ..... and beyond ..... to see if the problem is still there.

If it is, you boys have given me loads to work with ...

Thanks
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

[Glawseagle]

[malcolmt]