rough riding

[jojo]

hello all. First thank you all for the good tips i've been using for the past year. amongst all the bmw forums i've used, this one is from far the best around

 

My '04 1150rt has 22k on the clock and for the past 2k it's been running very rough. surging at any rev and 'farting' at decelerations. the 18k service been due anyway and thought after it was done i would get a smooth riding back again...I thought

here what i did:

new oil and oil filter

new air filter

new plugs (the 4 of them)

valve check and TB synch

change all brake / clutch fluid

new battery (baddly needed)

 

After all this, the problem was still the same.

 

I decided to let the dealer check the exhaust emission in case my air/fuel mix was dodgy....and it was! but it still didn't clear my surging and farting problem.

 

I will change the fuel filter and check the coils this weekend but since surging doesn't seem to be an issue on dual-spark boxer engines, I might be missing something here. Any suggestions are welcome.

 

Thanks in advance

george

[kzz]

I would suspect a jammed throttle cable near one of the throttle bodies.

[jojo]

update...

G'day. i changed the fuel filter yesterday as planned and went for a quick spin. straight away i could feel the difference in acceleration (no surging) and no backfiring at decel. re-did the tb sync as my idle had increased to 1500rpm.

it's a bike again!!

just a little note tho. the engineer at bmw must have designed the fuel pump assembly the day just after the beer fest in munich!! i've never seen such an awkward procedure for changing a fuel filter

 

regards

George

[JohnBeaven]

Only large hairy spiders have the necessary appendages to change a fuel filter on a oilhead BMW.

[DEF]

regards

George

 

Hello George,

 

Nice work.....curing your sputtering BMW on your own.

 

Even though your fuel filter change has mended your BMW, I would recommend some fuel system conditioner. Your symptoms sound very much like poor fuel, possibly laden with water.

 

The fuel system conditioner of choice here in the US is Techron. I am sure BP markets a good product in your part of the world.

[ShovelStrokeEd]

Or you could just toss a pint of isopropyl alcohol, you can get 70% or better purity at your local drug store, in there once in a while. Does most of what the rest of the fuel additives do. I actually prefer Sea Foam Injector cleaner for this duty. It seems to mix with the gas better.

[chrisstroh]

were you actually able to see dirt or brown come out of the old filter? Just curious.

 

Chris

[Laffo IBA#34115]

Wow! You are experiencing the exact scenario I am going through now. I also delayed my 18K service (did it myself) and at about 20K miles the bike started surging and missing. I took it to my closest dealer much to my regret and walked away very dissapointed. They acknowledged that it was indeed running poorly but did not know the cause. If I could leave it through the next week they could look at everything closer but they couldn't that day. On the way home I got a fresh tank of name brand premium gas and it started running better. I just chocked it up to a couple tanks of mini-mart gas. Don't know if the fuel filter was changed but they said everything was in spec including the valves.

[jojo]

thanks for your replies folks,

 

Or you could just toss a pint of isopropyl alcohol, you can get 70% or better purity at your local drug store, in there once in a while. Does most of what the rest of the fuel additives do. I actually prefer Sea Foam Injector cleaner for this duty. It seems to mix with the gas better.

 

in ireland we toss a pint of guinness rather that isopropyl alcohol!!

I actually put some STP engine cleaner. it says that it cleans everythings including valves and injectors.hope it does what it says on the tin!

 

were you actually able to see dirt or brown come out of the old filter? Just curious.

 

Chris

 

chris,

i didn't actually open the old filter but there was definitely some brown bits in the fuel that i drained from the tank. i didn't see any water tho

 

George