Bike missing at speed HELP

[Smeegles]

Hi guys long time no post.
I have an issue with my 1998 S where I am riding along at cruising speed but if I give it a fair bit of throttle NOTHING the bike lurches and does nothing so I try opening the throttle more and it gets worse like the engine has died but as soon as I back it off it's fine and then will do it again when I give it some.
this only happens in 5th and 6th from about 80-110 kmh which is not very encouraging when trying to overtake.
Is it a fuel problem?
It seems to happen in burts and not all the time.
At other times the thing flies.
It has done 66500kms and has been serviced regularly.

[bigblackfalco]

Most definately is the fuel filter blocked.The continual demand for fuel gradually gets to much at long stretches of high speed cruising.Change it ASAP.
Bailey.

[boxerpan]

Fuel filter inside tank or trapped fuel lines under tank.

[julian]

I know that 24k miles is the recommeded time to change the filter. Is it likley to get clogged at that mileage?

My mate bought a new fuel filter for the 24k service but hasn't gotten round to fitting it yet at 29k

[winger]

I changed my filter when i went to a big tank,bit like getting at the battery for the first time!!,but not difficult.

Chris

[bigblackfalco]

I know that 24k miles is the recommeded time to change the filter. Is it likley to get clogged at that mileage?

My mate bought a new fuel filter for the 24k service but hasn't gotten round to fitting it yet at 29k

Think my first fuel filter change was around 70K miles into the bikes life,but have gone sooner than that.They very rarely block completely,just give problems at continuous high speed crusin'.
Bailey.

[oyster]

The fuel filter (in any vehicle) is very vulnerable to water clogging. Changing the filter is a bit of a Chinese puzzle!

[Smeegles]

The fuel filter (in any vehicle) is very vulnerable to water clogging. Changing the filter is a bit of a Chinese puzzle!

Well the main suspect is water.
I put in a cup of methanol into the tank and the petrol went all "milky" then cleared up.
It didn't do any of the things it was doing in the last week so hopefully the problem is under control.
We shall wait and see.

[julian]

The fuel filter (in any vehicle) is very vulnerable to water clogging. Changing the filter is a bit of a Chinese puzzle!

Well the main suspect is water.
I put in a cup of methanol into the tank and the petrol went all "milky" then cleared up.
It didn't do any of the things it was doing in the last week so hopefully the problem is under control.
We shall wait and see.

When I changed the fuel filter on my old S at 24k there was a mug's worth of brown water like tramps' p*ss that came out of the bottom of the tank.

[Smeegles]

Nup
More of the same tonight but not as bad
'Gonna book it in to my mechanic.
Thanks for all the replies folks.

[Smeegles]

Problem solved.
It was the throttle position sensor.
As soon as I took it to my service bloke he plugged the computer in, ran the diagnostic and voila! TPS failure.
Changed and all is good.
Thanks for the advice folks.

[gus]

Glad you got it sorted.
gus

[theseadog]

Good to hear you got it sorted, never nice to have a problem that you can't seem to locate the cause of. Anyroads, was your 'mechanic' an independant or was it a BM dealer ?

Toodle Pip

[Neil178]

TPS? You must be gutted to miss out on the tramps piss ............

[Smeegles]

Good to hear you got it sorted, never nice to have a problem that you can't seem to locate the cause of. Anyroads, was your 'mechanic' an independant or was it a BM dealer ?

Toodle Pip

Independant bm mechanics and repairers complete with up to date instruments.
They work on bm's of all vintages and just outlaid $26000 for a new diagnostic computer for the new line of bm's
I wouldn't take it to a dealer in a pink fit as I don't know who would be working on it whereas the guys at Ringwood (Melbourne australia) are dedicated bmw repairers who know their stuff and all round good guys literally.