Low Speed Pulsing Issue

[lunc]

When riding at a low (under 25 mph) but constant speed, the power seems to pulse a little. It's difficult to describe. There is no real loss of power or speed and there's no scuffing sounds or alike but a definite change in engine note and it seems almost to miss and catch. It's similar to just moving your hand back and forth on the throttle a tiny bit but it's not that pronounced.

Braking and acceleration are fine and you don't notice it above 25 or at all after about 10 miles i.e. by the time I'm near work in slow traffic it's not happening.

I've had the disks checked and cleaned and one rear pad was un-seized but not changed out since it wasn't that bad.

Any idea's on what this can be?

 

[Ted]

Try getting the throttles balanced and the valves set up.
Could be "surging". Low engine speed, light throttle 2 big pistons going back and forth, may be slight imbalance in cylinders. Once warmed up less friction and better fueling.
How old is the bike or how many miles on it? Have 2 1200 gs in the family one with 7000 on the clock other with nearly 14000. older one smooth as silk down to walking pace other was just like yours till its warmed up. Better after 6000 service and as the miles get on it.
Just to be sure try getting to 25/30 mph pull in the clutch and see if the pulsing/wobble still there, if it is then check tyres if brakes oll ok.
Hope that helps.

 

[lunc]

Thanks I'll try that. Bike is a 55 plate with about 24K on it. It's recently had it's 24K service and and new front tyre and neither helped with this issue.

 

[ilkleyal]

Without a doubt, it is down to what is suggested above. Set the valves from cold first and then balance the throttle bodies. Hey presto.........

Al.

 

[Engineer]

When riding at a low (under 25 mph) but constant speed, the power seems to pulse a little. It's difficult to describe. There is no real loss of power or speed and there's no scuffing sounds or alike but a definite change in engine note and it seems almost to miss and catch. It's similar to just moving your hand back and forth on the throttle a tiny bit but it's not that pronounced.

Braking and acceleration are fine and you don't notice it above 25 or at all after about 10 miles i.e. by the time I'm near work in slow traffic it's not happening.

I've had the disks checked and cleaned and one rear pad was un-seized but not changed out since it wasn't that bad.

Any idea's on what this can be?

What gear are you in when this happens?

 

[lunc]

First and second for sure, maybe third as well but by then I'm usually going too fast to notice it. I haven't tied it to a particular gear.

 

[tw99]

Low speed surging (even when properly adjusted) was one of the widespread problems on R1150RS/RT, and thankfully seems to have been addressed on all the R1200 models, so it should be curable.

This maybe a stupid question, but are you sure you aren't holding the bars too tightly ? If you tense up too much, it can definitely cause that sort of effect as you end up moving the throttle in response the suspension movements.

 

[Johntee]

low speed surging

My GS 1200 feels like it's doing the same thing, very difficult to pin down. It does remind me of my previous 1150RT but not as pronounced as that. I also have just changed from a 700 Deauville ( nice bike but underpowered when two up) and that was a typical Honda - it had faultless fuelling right through the rev range so that may have spoiled me !!!
I will check with dealer if it can be balanced out, as it's under warranty, when we return from a jaunt to Ireland .

 

[Beemerman59]

My GS 1200 feels like it's doing the same thing, very difficult to pin down. It does remind me of my previous 1150RT but not as pronounced as that. I also have just changed from a 700 Deauville ( nice bike but underpowered when two up) and that was a typical Honda - it had faultless fuelling right through the rev range so that may have spoiled me !!!
I will check with dealer if it can be balanced out, as it's under warranty, when we return from a jaunt to Ireland .

Balancing of the throttle bodies is a service item and not a warranty issue - you will need to pay to have it done.

 

[tommygun]

Does the pulsing go away after a 50 mile or so motorway run? Could it be dodgy battery not producing sufficient spark through the coils? I fitted the Accelerator module to reduce this and it seemed to have worked at first, but am back to square one now. I've just learnt to live with it now.

 

[C-J]

The accelerator module fixes that sort of shenanigans

 

[chablis]

Surging at constant motorway speeds has previous been associated with a dodgy lambda sensor. There could be a link here with your problem.

 

[lunc]

This maybe a stupid question, but are you sure you aren't holding the bars too tightly ? If you tense up too much, it can definitely cause that sort of effect as you end up moving the throttle in response the suspension movements.

LOL. I suppose I might sound a bit like a teeth gritting caffeine soaked nutter gripping the bars so tight that the knuckles of my gloves go white, but I am actually a pretty relaxed and happy GS rider. Seriously though, I did think of that and I'm pretty certain it isn't the cause. It happens even on the rare smooth bit of tarmac. I haven't got the DT's either.

 

[lunc]

Thanks for the replies guy. I'll look at getting it balanced as "surging" seems most likely. It's not really a big issue but occasionally I worry that it is the forerunner of some sort of engine-based doom (or that I have Parkinson's).

Not sure about the accelerator module is for me yet as I'd like to be sure that there is no long term negative effect.

 

[Johntee]

Balancing of the throttle bodies is a service item and not a warranty issue - you will need to pay to have it done.

It's just been serviced!!!

 

[vee5]

Hmmm I've also noticed a slight "fore and aft" surge on my bike when cruising on the motorway - if this is possibly the lambda probe would this be covered under warranty do you know? (Its a 1200GSA with only 3000 miles on the clock.)

 

[mikewan48]

Just had the bike serviced (6000 + annual), mentioned that I was experiencing surging and when I got the bike back......luverly jubbley.....all gone and bike fuels better than new.
Was about the only thing spoiling the riding experience. So I guess that as I get towards a service it might come back but I'll wait and see how long it stays smooth between servicing.
Southport Superbikes by the way