R100GS collector box.

[Deleted account 111026]

I've read in the R1150 section about people using the R1150 collector box without a silencer and the noise level being acceptable.
Does anyone know how loud the later R100GS would be using just the collector box without the silencer?
I've seen a photo of a cafe-racer with this set-up and it looks very tidy.

 

[newbuild100]

VERY loud !

 

[Deleted account 111026]

You're certain it was the later R100GS collector and not the earlier triangular
R80G/S type?

 

[Rob Farmer]

Try it but I'd put your ear plugs in first

 

[Kenny]

Almost quite as loud as as the noise proff makes when someone drinks his Pussers

Yup, loud !!

 

[Beemerboff]

Something could probably be knocked up with a little bit of fiddling.

A Vello gets it lovely tone from an exhaust system which consists of a front baffle, which is a short piece of tube with a end cap and a few 1/4 " holes in the sides which is slipped over the end of the exhaust pipe and protrudes back into the muffler, which is otherwise empty, with the only outlets the few small holes in the sides of the fishtail.

On my GS there is a gasket between the collector and the front pipe, so a front baffle could be fabricated to fit in place of the gasket and protrude back into the collector box, and at the outlet a short piece of tube with one end squeezed together and a few holes in the sloping sides could be inserted into the outlet, forming a sort of reverse fishtail.

Or the collector could be cut open and a similar set up welded in. A decent exhaust shop could do it for you, and add a few plates to reverse the flow, and they would have a better idea of the correct number of holes in the baffles - it is surprisingly few.

Given the cost of a replacement muffler it would probably work out cheaper too.

 

[Deleted account 111026]

Thanks for all the replies. Looks like I shall have to make a silencer box to fit under the gearbox from scratch. I've done them before but a quiet collector like that of the R1150 would have saved a bit of work.

 

[stash]

Hi all. I have often wondered if a more throaty exhaust note could be achieved on my 100gs by drilling some holes in the silencer. It is a BMW stainless original item with header pipes and collector box in rusty mild steel with the chrome almost non existant so maybe time for a Y piece. Does anyone know how many holes and what diameter they should be and is it possible to drill down the end of the silencer to get the throaty sound i would like. I am not looking for earth shattering volume just something to reflect the presence of the big twin. Thanks, Stash.

 

[Rob Farmer]

A Y piece will blow your exhaust baffle to pieces in no time at all. I wouldn't worry about drilling holes.

 

[fayeslane]

A metal hole saw on an extension in through the exit end of the of the muffler works. Can't remember the exact size I used -22mm? There is a baffle plate about 20cm in. This mod gave the GS a nicer sound without being too loud. I'm pretty sure Beemerboff has done the same -must be an Aussie thing

 

[Beemerboff]

Yep , but the problem with mine was that the hole was blocked - Aussie beers cans will melt if you try and use them as gaskets at the header/ collector junction.

A hot spot on the mufffler alerted me to the problem.

There is also a baffle at the rear of the muffler - it is not fixed continously so it can be bent a little at the perimiter with a long screwdriver.

I uncliped the snorkels from the air box at the some time, result was a pleasing exhaust note, and a noticable improvement in throttle response, but others report total disaster , with no power anywhere.

But it is generally held that the restrictive silencer and air box cost Airheads 5/10 % power , so if you can get it right(fluke it ! ) the rewards are there, and free.

 

[fayeslane]

.

I uncliped the snorkels from the air box at the some time, result was a pleasing exhaust note, and a noticable improvement in throttle response.

+1 for snorkels

I managed to remove the rear baffle with hole drilling, a screwdriver and the dexterity of a proctologist

 

[Steptoe]

Hi all. I have often wondered if a more throaty exhaust note could be achieved on my 100gs by drilling some holes in the silencer. .

Simplest and cheapest method would be to record a throaty roar, load it on your ipod and ride around on the GS with the ipod at full volume.

That way you won't upset the highly tuned cutting edge performance of your GS for the sake of some noise.

 

[fayeslane]

That way you won't upset the highly tuned cutting edge performance of your GS

I don't think any of my bikes came with that

 

[stash]

+1 for snorkels

I managed to remove the rear baffle with hole drilling, a screwdriver and the dexterity of a proctologist

Maybe there is some Australian blood in my family as i am in favour of the opening up the silencer but a little hesitant as once i have drilled the rear baffle there is no way of going back if it effects the performance adversely. Would there be any logic in starting with a small hole, say 10-12mm in diameter and working up to a larger opening if things still seemed ok. I suppose there is no way of being sure but you Australians have always been ready to experiment and i like that. Thanks for all the comments and help, Stash.

 

[fayeslane]

Tried the small hole on my DR650 muffler -sounded like it had some serious gastric complaint Went bigger and it improved responsiveness, sounded OK without being offensively loud.

On the GS with snorkels removed and baffle removed the bike felt more responsive.

 

[(RIP) maverick]

Simplest and cheapest method would be to record a throaty roar, load it on your ipod and ride around on the GS with the ipod at full volume.

That way you won't upset the highly tuned cutting edge performance of your GS for the sake of some noise.

Ohhh there's an idea, a GS with a Harley roar!

 

[fayeslane]

Ohhh there's an idea, a GS with a Harley roar!

To me the Harley roar sounds like a wet fart

 

[Benjamin M]

To me the Harley roar sounds like a wet fart

All too often, that is exactly what it is

 

[stash]

Yep , but the problem with mine was that the hole was blocked - Aussie beers cans will melt if you try and use them as gaskets at the header/ collector junction.

A hot spot on the mufffler alerted me to the problem.

There is also a baffle at the rear of the muffler - it is not fixed continously so it can be bent a little at the perimiter with a long screwdriver.

I uncliped the snorkels from the air box at the some time, result was a pleasing exhaust note, and a noticable improvement in throttle response, but others report total disaster , with no power anywhere.

But it is generally held that the restrictive silencer and air box cost Airheads 5/10 % power , so if you can get it right(fluke it ! ) the rewards are there, and free.

Just to say that i drilled the 22mm diameter hole in the silencer baffle plate and then removed the snorkels. Well i was a little hesitant if truth be told as it would be impossible to fill that hole again as it is about 300mm from the end of the can. Anyway, fired her up and went for a spin. The result seems to be a very noticable positive engine response with a nice barking sound when cracking the throttle open. Thanks for your advise, it seems to have worked well. The only doubt i have is about water being driven into the air filter and airbox, is this likely to cause problems? or will it just escape through the rubber valve that is situated in the base of the airbox. Thanks once again, Stash.