LEADED FUEL ON A R1200GS

**SHAKABRA** · #1 5 Sep 2005

IF I CHANGE THE STANDARD EXHAUST AND PUT A AKPOVIC SYSTEM ON IS THERE ANY CHANCE I CAN USE LEADED FUEL IF I HAVE NO OTHER CHOICE OF FUEL (NO UNLEADED AVALIABLE) THE CAT WILL BE OUT OF THE SYSTEM SO THAT WONT CAUSE A PROBLEM BUT IS THERE ANY THING ELSE I MUST WORRY ABOUT

**Tim Cullis** · #2 5 Sep 2005

Looks like you are OK. Here's a discussion link: http://www.bmw-motorrad.co.za/lifest...play.asp?Id=37

Tim

**Margus** · #3 5 Sep 2005

Just came from Iran, where's mostly leaded fuel (on some bigger cities you may get the "super" option=unleaded, but quite rare) i have R1100GS with Cathalythic converter and Lambda (O2) sensor.

Some people say Lambda sensor will be poisoned by leaded fuel very quickly, also the cathalythic converter will die.

But after riding thousands of kilometres in Iran with a friend having R1200GS with Lamda and Cat bot too, i say you'll have no problems. Bikes work fine, just a bit more valve noise on low rpms (poor quality fuel and low octan), a bit more fuel consumption and i first time experienced this so called BMW boxer's "surging effect" on some around 3000 revs when accelerating on cold engine in the morning, but in very minor way. I think surging is because Lamda sensor is poisoned but lamda sensor is only for making engine perfectly smooth on all conditions and revs, if lambda is not working, then engine still works OK, just few more "quirks" on some situations (as mine surges when engine is cold).

So don't worry, you'll be OK in eighter case - wether it's stock exhaust or aftermarket without Cat!

Cheers, Margus

**Frank Warner** · #4 6 Sep 2005

Once the lambda sensor is poisoned the system goes to a default map. This may increase the fuel consumption.

Replacing the lambda sensor (say $100 for a nonbm part) will get you back to 'normal'.

Removing the lambda sensor before you poison the sensor will save you $100 and still give you the default map. A plain bolt can be used to fill in the hole left behind.

Your choice.

**Frank Warner** · #5 6 Sep 2005

Errr on the R12 I think you will find there are two lamdba sensors - one for each cyclinder ... so total costs would be doubled.

**SHAKABRA** · #6 6 Sep 2005

SO WHAT YOU SAYING IS REMOVE THE SENCOR FROM THE BEGINNING BEFORE FITTING A NEW PIPE AND I WONT HAVE A PROBLEM SO DO I DISCONNECT THE SENSOR FROM THE ENGINE OR LEAVE IT CONNECTED AND SECURE IT TO THE BIKE AND THE LOW DOWN ENGINE NOISE IS THAT NOT THE VALVE SEATS BEEN EATEN AWAY