Exhaust System?

[REGS12]

I love my GS12, and am happy with the way it silently hustles other bikes, but now and again It'd be nice to be a bit nastier. Was reading an article about an exhaust system made by BOS in Holland I think. They claim 5.3 HP gain at 2760 RPM, while complying with the sound police. ' Sounds' pretty good, but has anyone tried it?

 

[Tim Cullis]

I know someone had one fitted and was going to give opinions, but a search for BOS doesn't bring up any matches. South London Motorcycles (BMW dealer in UK) has them in stock and they look well made.

One of the german bike magazines did an in-depth on 1200GS exhausts and AFAIR none of the replacements did as well as the original which has an internal bypass value to improve mid-range (cuts the wave-length of low pressure waves so they arrive at the exhaust port in time to help scavenge the exhaust gases).

Tim

 

[Tim Cullis]

I found a link to the german bike article on the BOS site: http://www.bos-exhausts.com/bmw-eng-pond/bmw-r1200gs-test.html. Click on the first item (Test 1200GS). The BOS system came out best.

I'm note sure whether these tests were done with or without the DB eater in place. I presume they were with the standard header pipes rather than with the cat eliminator. There's some dyno graphs elsewhere on the site.

Tim