Free smoother running

[Nick dj]

Recently removed my standard headers and noticed that the exhaust flange is welded on and although it is machined and polished on the outside the inside weld is left totally untouched.
It narrows the exhaust as it leaves the cylinder and is all blobs of welded stainless. I put one of the round sandpaper flap discs on a drill and spent 20 minute's smoothing it out.

The bike certainly seems to pick up a bit lower down and run better, it could be just in my mind but surely a smoother round exit to the cylinder must be better?

Anyway its free and takes about an hour, I also polished up the headers whilst off so spent a bit longer, all looked great when it went back on.

Just a thought.

 

[wildbeeste]

I don't know why but the phrase "Fur coat and no knickers" comes to mind when I hear about the BMW engineering

 

[Ali-bear]

I recently fitted de-cat headers and they do make quite a noticable difference. Not sure a bit of extra metal at the top of the pipe would make as much of an obstruction as the whopping great cat blockage!

 

[King Key]

Did you need to adjust the tune when the cat was removed?

 

[Ali-bear]

I would say that its a good idea to. I fitted one of those things that adjust the intake air temperature sensor reading.

 

[Bendy toy]

Did you need to adjust the tune when the cat was removed?

"One Tune to the Song of Another" must not be confused with "One Song to the Tune of Another".

The first is a well known panel game. The latter is of course Bill singing while Tim sucks on a mentholated sweet.

Apologies to Humph

 

[King Key]

Thanks Bendy, that cleared that up.

 

[Bendy toy]

Happy to help


Sent from my iPhone using Tapatalk

 

[Nick dj]

I recently fitted de-cat headers and they do make quite a noticable difference. Not sure a bit of extra metal at the top of the pipe would make as much of an obstruction as the whopping great cat blockage!

I would agree normally but have you seen the inside? It is a real mess and reduced the pipe diameter by about 15% or more and set up a terrible air flow.
Could this be part of why an Akro or Remus header makes some much difference, along with the decat.

I only posted this because I know it worked so well on mine

 

[Bendy toy]

The bike has 4 valve heads followed by crummy welds, so a bit of time with a Dremmel has got to be worth doing. Lumpy welds where the gas is moving fastest can never be good.

The Remus stainless header with standard can made an immediately obvious difference over standard especially in the mid range.

It would be great to see the incremental effects of each change on a dyno.

 

[Ali-bear]

I would agree normally but have you seen the inside? It is a real mess and reduced the pipe diameter by about 15%

I'll take another look inside the tops of my old header pipes, but I don't remember it being occluded. I only hope I can avoid the temptation of playing it like a trombone. Compared to my working days at the moment this seems like a good idea and comparatively productive.