3-in-1 BSM exhaust SFC 1000

[Garry]

Sometimes you come across something and think, ‘Yeah, I’ve got to have that,’ but you know full well beforehand that you might not use it at all...
That’s exactly how I happened to come across a 3-in-1 BSM exhaust for an SFC 1000. I’ve already given it a good polish. I’m familiar with BSM or Janton exhausts from back in the day, having had one on my Suzuki GS 1000, and it’s a quiet exhaust. That’s what I prefer.

I’m missing the centre stand stop. Does anyone have any idea or an example of another 3-in-1 system showing what such a centre stand stop looks like?

As it’s for an SFC, it won’t just fit straight onto an RGS, so I’ll have to make something. The headers, by the way, are 38mm in diameter, so larger than standard...

Is anyone else familiar with this BSM exhaust system?

Of course, I may just leave the standard exhaust system in.

 

[sfcpiet]

Garry,

The RGS has basically the same mounting points as the 1000 SFC, their silencers were identical bar a couple of extra holes in the end cap.

The mounting point in your pic looks more like it's intended for a 180° frame.

I once had a BSM system on my 3C. Was nice and quiet but choked the engine to a 170km/h top speed. I proceeded to gut it and found a serious restriction in the 3-1 collector portion, whole thing went straight to the bin...

piet

 

[Paul Marx]

Doesn't look very efficient.
Paul

 

[piranha-bro2]

Plenty of back pressure with that exit hole!! Why use larger ID headers and then try and squeeze it out through a 1/2 inch tube?! Form over function ...

 

[chrisk]

Plenty of back pressure with that exit hole!! Why use larger ID headers and then try and squeeze it out through a 1/2 inch tube?! Form over function ...

There a joke about an elephant asking a bloke, who taking a piss in the jungle and the elephant says, How the hell do you breath through that? But as this is the Tech section I won’t tell it.

 

[Garry]

Garry,

The RGS has basically the same mounting points as the 1000 SFC, their silencers were identical bar a couple of extra holes in the end cap.

The mounting point in your pic looks more like it's intended for a 180° frame.

I once had a BSM system on my 3C. Was nice and quiet but choked the engine to a 170km/h top speed. I proceeded to gut it and found a serious restriction in the 3-1 collector portion, whole thing went straight to the bin...

piet

Piet, I’m not going to be doing 170 km/h here in the Netherlands. At those speeds, you’re on the same level as a top criminal here...

Besides, the nice roads here are already limited to 60 and 80 km/h and, unfortunately, not 100 km/h like in your country.

I’m very happy with my standard exhaust, but I thought the advantage of this 3-in-1 was that it would be easier to clean the oil filter without having to remove the exhaust system, and to maintain the drive chain.

I think I’ll have to accept my loss and follow my heart less and my mind more.

I think the BSM will end up hanging from the garage ceiling like a kind of trophy.

Here’s a quick photo of the rear where the three headers meet.

 

[sfcpiet]

Garry,

IIrc, the restriction was just before the "silencer" began, invisible from the outside, behind the bend. If endoscopes had been as freely available back then as they are today, I may have found it and been able do something about it without needing to cut the thing up.

Not only was the top end restricted, the whole rev range came alive when the original system was re-fitted. I recieved the bike with the BSM system fitted and thought it was the dogs bollocks at first. TÜV inspection was due, so the OE system needed to go back on. Learnt a lot at the first proper twist of the throttle!

piet

 

[jko_78]

Not a Laverda, but I had a BSM exhaust for a while on my 21 hp Kawasaki KL250 off-road. The originals rusted out within a week, found a cheap used BSM system. When I fitted that, it sure was quiet*, it felt like 10 hp from the original 21 were missing...very restrictive. And on a small bike like that you notice really quick.

Then ran a part of the original system, that came with the scruffy old bike, with a Laverda 750 slash-cut silencer from my fathers parts box (in fact, now that I think of it, it may have been an original to my 750!), a bit too loud for early mornings perhaps, but it ran great with that -until I found KL250 gold, an orginal-non rusted out 1 piece exhaust. A bit more restrictive than the Laverda obviously, but as quiet as the BSM, but far less restrictive.

*my KL250 came with part of a the original system, but the silencer(s) replace with a British(?) cone-type, when the end cone flew out it became a rather loud megaphone...