R1200GS BOS Exhaust system fitting

See also:
BMW R1200GS Exhaust Systems, Cans & Exhaust Modifications

TIPS!
~ check the correct tightening torque specifications (look here😉
~ on assembling exhaust parts i.e. where ‘Y’ piece slides onto header pipes, end can slides onto end of ‘Y’ piece, apply an anti-seize compound such as Copper Ease
~ depending on the age/mileage of your bike – be prepared to buy new header to cyclinder head gaskets (maybe just buy them in anticipation)


BOS Exhaust fitting, with pictures
By ukGSer Grizz

I fitted a complete BOS Carbon and Stainless exhaust system to my 2006 R1200GS. Here’s a pictorial of the process with some basic instructions.


This is by no means a professional account of how to do it, just a typical white collar worker saving a few pennies 🙂

New BOS full exhaust system (also fitting a K&N Filter).

Firstly, park the bike on centrestand on a flat level surface. Remove the OEM BMW original exhaust tailpiece.

Disconnect the Lambda sensors (Oxygen / O² sensors) and unscrew – note the securing tag/clip indicated by screwdriver point.

Remove bashplate / sump guard. (Why would there be 3 different types of nut/bolt?! – in 12 and 13mm)

Unscrew the header pipe fixing nuts from the cylinder heads

The header pipes will come loose once the retaining clamp on the catalytic converter is undone.

The Catalytic converter clamp needs to be undone.

Also pry loose the cat clamp hanger with long screwdriver or similar.

Wiggle (with some care so as not to damage anything) and whole lot drops out.

At this point it is time to start adding the BOS system and its bits…. DO NOT TIGHTEN ANYTHING UNTIL EVERYTHING IS IN PLACE.

New hanger bracket slipped over hanger pin.

New headers in place.

Connecting pipe (‘Y’ piece cat replacement) in place.

At this point hang the end can from hanger using original hanger bolt. Adjust so as to maximise slip on effect. Springs in place too. Leaving all securing bolt/fixing loose so far helps 😉

Springs tightened, and all allen head, Torx, and other nuts and bolts tightened to specified torque settings.

Start up bike……………..and grin madly 🙂

R1200GS Test ride
I hate story tellers when it comes to performance…. louder is not always faster. I really do not know what the truth is today.

However, it is winter, roads are wet, salted, slippery, and generally not to riding like a twat (Not that I do that, or condone that sort of riding)

I did only 20 miles, went to Maidstone , Machine Mart to buy a 6 inch bench Vice for the garage, and then back. There are a few roundabouts on the way, some curvy bits and some straights. My riding style is probably best described as “Brisk” but I have no points on my licence yet as testament to that. 🙂

Going there, I rode sensibly, traffic etc.
Comming back at one point I rolled on the throttle in 2nd or 3rd and the front end became light and must have lifted an inch or so off the road, now I have never wheelied intentionally in my life, at least not since flipping a TS125 when I was 14 years old, and had to explain to my Dad . Over the years I have had bikes raise front wheels, but then only when accelerating hard to beat traffic etc, and clearly the usual offroad type air, but never intentional or skilled wheelies.

Now to the point of that longwinded explanation……

The bike on not even brisk acceleration today on the way back, in 1st, or roll on in 2nd and 3rd gears kept on heading for the sky, again, I say inches, not feet.

I would like to say that the sound is good, and not at all intrusive (Decibell killer in place) so cancelling out “sounding faster” I would say there is deffo more to this bike now with the BOS full system, I have not added the K&N filter yet either, as I needed to get mobile this morning.

End result: Chuffed to bits, and I will have to be aware that there is a bit more go to this bike now than the more than ample before.

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