Engine fuel/surge issue help

[bushboy]

Hmm issue.

Just started over the weekend. When riding along at approx 70 mph, 3500 rpm approx. Engine surges. feels like it drops onto one pot, then clears as soon as I apply a small amount of throttle.
any ideas? thought might be exhaust sensor as maybe a mixture issue?

Anyone had any thoughts.

If not a easy fix off to bmw to get ripped off to have it sorted.

Cheers

 

[Gas'd Off]

Maybe try synchronising the throttles?

 

[Steve]

When riding along at approx 70 mph, 3500 rpm approx.

Drop it down a gear and ride at 4500 rpm.

Problem solved. No charge.

BMW would have charged you an hours labour for that advice.

 

[Timolgra]

coil

 

[Steptoe]

Is it a twin spark - if so check the main plug coil caps .

Pull off the lower spark plug caps and see if runs on both cylinders.

If one is missing or cutting out, swop the main plug caps over and see if the problem moves with it

 

[bushboy]

Still not good

Thanks all for the tips.
It is a 2002 model 1150 GSA. Not the twin spark model.
Carbs are balanced Check
Coil, bit hard to tell but assume OK as only at a certain rev range
Changed plugs, still does it.
Will have a bit more of a play and see what the crack is but hard with out all the diag tools.

Cheers all.

Casey

 

[Snooky]

If it isn't the plug caps then possibly the Halls sensor, which as I found out is reasonably expensive from B*W

 

[Timolgra]

If it isn't the plug caps then possibly the Halls sensor, which as I found out is reasonably expensive from B*W

But £40 S/H from Sherlocks

 

[sk8mutie]

bush, i had something very similar, and diagnosed one part of the problem... worn throttle body spindle bearings...was ticking at idle, and when you put your finger over the inboard side of the spindle casing, it stopped...was quite a bit of play on it...bike had about 20k on it, year old.

this gap then allowed air in/out on one side. was covered under warranty, and when they checked, the coil packs were breaking down too.

bike was fine up to about 70mph steady steaming, or if i had a steep hill, or a pillion to carry....other wise, there was no indication