Brake servo running constantly..

[steadysteve]

Just bought an 1150GS project , 03 reg, and the servo is running constantly once it has been triggered by applying the brakes. It switches off when the ignition is switched off and stays off until the brakes are applied again.

The brake lights go out when the brake lever and pedal are released.
New battery fitted.

Just wondered if anyone knows what the problem might be please?
Thanks

 

[Steptoe]

Questions questions questions.
Has it just started doing it ?
Was it doing it before the new battery was fitted ?
Do you not know if it had the problem previously because you've only just bought it as a non runner project bike and it needed a new battery ?

 

[steadysteve]

Questions questions questions.
Has it just started doing it ?
Was it doing it before the new battery was fitted ?
Do you not know if it had the problem previously because you've only just bought it as a non runner project bike and it needed a new battery ?

Not sure on any of those questions...
The previous owner claimed to have no idea on mechanical stuff. He had it mot`d and new battery fitted the day before I picked it up. I didnt notice the servo when I picked it up-- It runs but was running rough, very rough with a noisy exhaust coughing and farting so didnt notice the servo but when I got it home the choke cable was sticking so I am hoping that was the cause of the rough running.. not had it running today, tank still off.

I thought it might be a sticking relay, after making sure the brake lights were going out. Seem to think the brake light switch trips the relay to power the servo??
Cheers.

 

[The Grey One]

Have you checked the fluid level in the two reservoirs under the tank as well as the one on the bars and above the brake pedal?

John

 

[steadysteve]

Have you checked the fluid level in the two reservoirs under the tank as well as the one on the bars and above the brake pedal?

John

No, will do tomorrow. Low level causing the pump to keep on trying to build pressure do you think?

 

[The Grey One]

No, will do tomorrow. Low level causing the pump to keep on trying to build pressure do you think?

Possibly, in any event you don't want the servo working if the levels are low.

John

 

[steadysteve]

Thanks john.
Didnt notice the other fluid reservoirs- thought there was only the two on the master cylinders.

 

[The Grey One]

Thanks john.
Didnt notice the other fluid reservoirs- thought there was only the two on the master cylinders.

Two of them on top of the servo block, both have plastic tops with spill off pipes attached. There is a procedure for this. You don't need the special filler adaptor some mention, a small funnel works fine. If I were you I would bleed the entire system through until it is full of fresh fluid.

John

 

[Flipfly]

My advice......bin the servo and make it non abs. The brakes are much nicer and you'll never have to worry about the brakes failing.

 

[flatdog]

Rough running.

May I add that it's not a choke, that lever just raises the idle speed to assist cold start so there is no change in fuel mixture.

 

[Beebop]

I had the same issue on a recent trip.
It turned out to be the metal tab which depresses the micro switch.
I bent it a fraction and problem went away.

 

[steadysteve]

Thanks all- tempted to remove the servo but it sounds healthy enough and the abs works afaik. Passed mot so I assume it has to work if fitted.
Hopefully the rough running will be sorted by a good service and binning the K&N filter and remus can.

Beebop, I will have a look at that. Where is the microswitch? Thanks.

 

[The Grey One]

Thanks all- tempted to remove the servo but it sounds healthy enough and the abs works afaik. Passed mot so I assume it has to work if fitted.
Hopefully the rough running will be sorted by a good service and binning the K&N filter and remus can.

Beebop, I will have a look at that. Where is the microswitch? Thanks.

I think a lot of servo failures were down to not changing the fluid regularly. Removing the servo means no abs which feels like a big step backwards to me.
I can't comment on the K&N filter as I have never fitted one but I have a Remus can and Y piece so I can tell you these are not a source of rough running.

John

 

[Beebop]

Thanks all- tempted to remove the servo but it sounds healthy enough and the abs works afaik. Passed mot so I assume it has to work if fitted.
Hopefully the rough running will be sorted by a good service and binning the K&N filter and remus can.

Beebop, I will have a look at that. Where is the microswitch? Thanks.

Switch is under the front brake lever.

 

[steadysteve]

Switch is under the front brake lever.

Cheers.
Servo stays on after either brake has been applied but will check it out.

 

[Flipfly]

I think a lot of servo failures were down to not changing the fluid regularly. Removing the servo means no abs which feels like a big step backwards to me.
I can't comment on the K&N filter as I have never fitted one but I have a Remus can and Y piece so I can tell you these are not a source of rough running.

John

Until you ride one with the servo removed, then you'll realise that the direct connection between brake pad and fingers is far far better than servo brakes. Dumping .the servo is a huge improvement to the brakes. You may lose abs but the safety aspect of abs is far outweighed by having no brakes at all if the servo fails. In the lottery of life I'd rather take my chances with non abs brakes when I need them than potentially have abs or no brakes.

The servo can sound fine, it'll give you very little if any warning when it's going to leave you with no brakes at all. I will guarantee that the chances are it'll fail when you need the brakes (i.e. When you pull the lever to slow down).

 

[The Grey One]

Until you ride one with the servo removed, then you'll realise that the direct connection between brake pad and fingers is far far better than servo brakes. Dumping .the servo is a huge improvement to the brakes. You may lose abs but the safety aspect of abs is far outweighed by having no brakes at all if the servo fails. In the lottery of life I'd rather take my chances with non abs brakes when I need them than potentially have abs or no brakes.

The servo can sound fine, it'll give you very little if any warning when it's going to leave you with no brakes at all. I will guarantee that the chances are it'll fail when you need the brakes (i.e. When you pull the lever to slow down).

If I spent my life worrying about things that might happen I would never ride a motorcycle.

John

 

[Flipfly]

If I spent my life worrying about things that might happen I would never ride a motorcycle.

John

No need to worry once the god awful servo is removed

 

[The Grey One]

No need to worry once the god awful servo is removed

Each to his own, I have managed so far and with decent maintenance I think it will continue to function.

John

 

[tadhgocuilleain]

On the rough running: check that the throttle cables are seated properly. The battery was replaced, so there's a good chance that's what's wrong.

http://www.ukgser.com/forums/showthread.php/92541-Why-s-My-Bike-Running-Rough-A-Common-Fault

I agree with FlipFly about removing the servo. Like you, I was adamant not to remove my servo when it was working because I thought regular servicing would keep it working. It failed at 30k km. It was immaculate inside but a pressure sensor inside had failed. Luckily, it failed when I was bimbling along a country road, not riding at speed. You seem to have your mind made up, though, and I know how annoying it is when someone on a forum tries to convince you of something you don't agree with, so I won't say any more.