K11 Owners Group

Glawseagle

Gents,

Need some help.

My 1998 K1100LT has developed a misfire under load.

I can cruise along at 60mph at 4000 revs in top no problem, but once I try to acceleate the bike loses power, starts to bang, splutter and misfire.

This doesnt happen all the time, sometimes the bike performs superbly and seems to be ok if I accelerate gently.

But if I pull the throttle back, as in overtaking, the bike all but dies.

We took the petrol out, cleaned the tank and fuel system, (thnking it was sub standard petrol), added octane improver and it improved for a while.

Now the problem is back.

Any ideas?

Have I used substandard petrol and this has given me a problem with the injectors?
Is the problem electrical as in a short somewhere, maybe a coil?

As usual, all advice appreciated?

Cheers

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

SugarHillCTD · Posted: Sat Feb 13, 2010 7:14 am Post subject:

Dave,

Did you change the petrol filter inside the tank?

I think that you are more likely to find the problem in the fuel system than in the electrical BUT are all your ground connections clean and TIGHT?

Just before the problem started, had you done any work on the bike?

Others will be along soon to add their input.

Good luck,

John
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John & Cathy

'92 K100RS4V Pearl White SOLD
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Off the grid · Posted: Sat Feb 13, 2010 12:34 pm Post subject:

Check the tightness of your plugs in the head and the plug wires...all of them. Happened to me. 2 plugs were hand-loose.
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Phil Marvin · Posted: Sat Feb 13, 2010 1:44 pm Post subject:

Hi, Dave,
My '96 K1100LT had similar problems. I changed the plugs and the fuel filter. It helped slightly (it was time to change them) but the problem persisted. I finally took it to my local BMW dealer. The mechanic put it on the MoDiTec and the answer was the Throttle Positioning Sensor. He changed the TPS (adjusting didn't work). The problem was solved. It ran like a scalded dog up until I sold it, and I believe the purchaser is still riding it and has not had this problem return.
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Ride Safe,
Phil Marvin in El Paso, TX
'94 K75A/3
'95 K75RTP

RJTrucker · Posted: Sat Feb 13, 2010 3:16 pm Post subject: Misfire

When my K11 was sputtering and misfiring under load it was clogged and dirty fuel injectors. I sent them to Mr. Injector for cleaning and has been running fine since then. I also changed the plugs when I put in the new injectors cause they were not all the same color cause of the lack of fuel in one of the cylinders.
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1993 K11LT
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1974 R90/6

Glawseagle · Posted: Sun Feb 14, 2010 6:32 am Post subject:

Glawseagle · Posted: Mon Feb 15, 2010 2:46 am Post subject:

A quick update ....

I put normal petrol in today, 95 RON as opposeto 98 RON ….. and its worse …… very much so.

This is driving me mad.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

Ragman · Mad Brick Rider Joined: 26 Mar 2008 Posts: 97

My bike was doing the same thing. I ran some Sea Foam in a tank of gas and it started running great and has for the last 15K.
May be worth a try.
Ragman
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1995 K1100LT
1980 Hadley Giggleson FLHC

drikko · Posted: Mon Feb 15, 2010 3:29 am Post subject:

If 95 made it worse then I would suggest the timing has slipped for some reason. Can you check the timing?
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Glawseagle · Posted: Mon Feb 15, 2010 7:44 am Post subject:

I dont suppose it has anything to do with the injectors requiring cleaning?

• It seems like the bike performs well if I use Octane additives.

• Not so well if just ran on 98 RON petrol.

• And runs like a dog if using normal 95 RON petrol.

That says to me, the engine requires something extra to make it perform as it should, and that it is not running efficiently.

Worth a try for £4 I suppose.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

Technician · Posted: Mon Feb 15, 2010 12:31 pm Post subject:

Have you checked the plug leads. No3 is prone to breaking down i've had to deal with two bikes in the last 3 months that have suffered similar symptons and changed the leads to fix.
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Glawseagle · Posted: Tue Feb 16, 2010 3:04 am Post subject:

Update:

I added injection cleaner to a full tank of RON 95 petrol, and after a few miles the bike picked up, the mis-firing/spluttering stopped and the bike returned almost to normal.

I have now done around 50 miles since I added the injection cleaner and the bike is a lot, lot better. It pulls like it should, with only intermittent mis-firing when I open the throttle wide..

It still isn’t perfect but I feel progress has been made. I suppose the next step is to add more injection cleaner with my next tank of petrol unless someone has a better idea?

Will I have to manually clean the injectors? Or replace them?

On a relating point, I had an interesting conversation with a Trading Standards Officer yesterday. To cut a long story short, he said …. “only use branded petrol, i.e. Shell, Esso, and avoid Supermarket, and in particular Tesco, Petrol like the plague”.

I feel that the main problem has been the clogging up of the fuel injectors through using sub standard supermarket petrol over the last year.

No more Tesco’s for me.,
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

Phil Marvin · Posted: Tue Feb 16, 2010 3:45 am Post subject:

Hi, Glawseagle,
In my opinion, you have been fed a line of bullsh*t. I regularly fed my K1100LT's (and currently feed my K75's) the cheapest petrol I can find. This mostly means off-brand stations. I also, at times, fed my K1100LT's regular unleaded (91 octane, using your method of measuring octane) and neither ever sputtered or misfired except, as I already said, when the TPS went bad. Once you find and fix your bike's problem, whether clogged injectors, bad TPS or whatever, I think you can use whatever petrol meets the specification, which is 95 octane (Research Method).
_________________
Ride Safe,
Phil Marvin in El Paso, TX
'94 K75A/3
'95 K75RTP

Glawseagle · Posted: Tue Feb 16, 2010 5:16 am Post subject:

Hi Phil,

I think the main priority is the get the bike fully working then decide the way forward.

Hopefully more injection cleaner will sort it.

I cant really afford to go through the crap I have been through lately so I may err on the side of caution and avoid cheap petrol.

Once this last bit of misfiring is sorted I will probably put the bike in for a full service.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

MadStu · Joined: 12 Nov 2008 Posts: 22 Location: Brighton, UK

I find Shell Garages are some of the cheapest garages around anyway, and besides, it doesn't make much of a difference to price. If it's 2p a litre more than Tesco, then you're not going to be paying more than 40p a tank more!

I've had a similar problem lately though, and my bike has totally stopped working. Sad

I've checked spark plugs and fuel filter, I am going to check TPS, but can anyone give advice on how to check timing?

Thanks.
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1994 K1100LT

Flying Duck · Posted: Wed Mar 10, 2010 6:12 pm Post subject:

You need to take the cover off of the Hall Effect sensor and use a timing light. You adjust by loosening the bolts hold the HES and rotating it.
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Glawseagle · Posted: Thu Mar 11, 2010 6:01 am Post subject:

Final Update:

Ran 300 miles on higher grade petrol, the last time within 10 miles of the reserve light coming on.

No problems.

Filled up with normal octane and agan no problems.

The bike is absolutely pulling like a train, better thsn it has done.

So, problem solved.

Thanks for all the help, guys.

Lesson learned?

DO NOT BUY SUPERMARKET, (TESCO), PETROL UNDER ANY CIRCUMSTANCES.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.

Tim (Midland Section) · Posted: Fri Mar 12, 2010 9:43 pm Post subject:

Glawseagle · Posted: Mon Mar 15, 2010 9:05 am Post subject:

Well, I spoke too soon.

After 500 miles of trouble free riding, the mis-fire spluttering is back.

I had just filled up with RON95, (for the second time), and 10 miles later, the problem re-occurs. ... exactly like it was two weeks ago.

There must be some crap somewhere in the fuel lines, and maybe its dislodged when I filled up.

Honestly. .....

Will run this tank full down and fill up with high octane to see if that helps.
_________________
"Lovely stuff" ...Not my words Michael... the words of Shakin' Stevens.