Header diameter increases

[Will14]

Can I ask what modifications you have done please? I have a better looking power curve but the numbers are way down on yours, although she pulls like a train. My bike was in standard trim other than a pair of Delkevic cans

https://www.youtube.com/watch?v=eFSN593UieE

[Snapey]

I can't remember what 14 you have but the K5 onwards headers are larger than the early ones due to being single skinned.

Totally wrong Hooli. Both chrome and stainless headers are double skin. Stainless outer is slightly bigger but the internals are the same.

[Hooli]

That's never been the person perceived wisdom on here, but if you've got anything to show that I'm happy to be corrected.
I've never had standard late downpipes off myself so just going on what others have always said over the years.

[KiwiCol]

I don't know the diameters, but I do recall Pete doing some work on the exhausts & had pic's of them off and he was measuring the internals from memory.   So if he says they're the same, my coin is on Snapey with this one.

[Pommeroy]

Search "header pipes for k2" and you'll find that discussion, from 2019. I don't know how to link to it, or copy from it.

Admin added
On behalf of @Pommeroy this is the link https://gsx1400owners.org/forum/index.php?topic=4448.msg57987#msg57987

[CROS]

Oh I forgot one other thing, there's normally a dip/flat spot around 3.5k as the timing is retarded there so the bikes passed the drive by noise test in type approval. It shouldn't cover as big a range as your rough bit, but it does mean it'll never look a perfect curve. You can't feel it as you ride though.

The bike is fitted with a TRE (timing retard eliminator - tells CPU that bike is in 6th gear all the time so no rev limit) so this should not occur

[gsxbarmy]

TRE's are a complete and utter waste and generally the majority do nothing at all. In over 19 years of owning and working on 14's and being on 2 GSX1400 forums (this one as admin and on the previous GSX1400.org), I've never yet seen a good word said about them, nor anything that claimed they had any real effect - in fact some TRE's in the past actually caused wiring issues and overheated, catching fire.

Personally I'd junk the TRE- if you want to change your timing, do the timing plate mod, much safer and works.

https://gsx1400owners.org/forum/index.php?topic=144.0

[grog]

Sorry Dave, my Healtech been fitted 14 yrs, never a prob. Gear indicator included, i like that also. If i turn it off, much rougher around town.I dont like backing plate mod as 5&6 gears then go another 4 degrees, they are not retarded to start with, too much imo. All i have to say.   

[gsxbarmy]

Sorry Dave, my Healtech been fitted 14 yrs, never a prob. Gear indicator included, i like that also. If i turn it off, much rougher around town.I dont like backing plate mod as 5&6 gears then go another 4 degrees, they are not retarded to start with, too much imo. All i have to say.   

Healtech are good @grog, and in their case the TRE element does work - as I said in my previous post, its the majority that don't. I never had the TRE element of my Healtech gear indicator engaged as I used the had a timing mod done instead

[CROS]

Can I ask what modifications you have done please? I have a better-looking power curve but the numbers are way down on yours, although she pulls like a train. My bike was in standard trim other than a pair of Delkevic cans

https://www.youtube.com/watch?v=eFSN593UieE

Hi, engine has had Yoshi ST1 high lift cams and has been ported and flowed (a few other tricks from race team mechanic). This accounts for most of the difference plus tuning in to Power Commander 6. I have just posted a couple of pics. I will likely go to a new header system though.

[Snapey]

That's never been the person perceived wisdom on here, but if you've got anything to show that I'm happy to be corrected.
I've never had standard late downpipes off myself so just going on what others have always said over the years.

This is from a K5 Hooli. Stainless outside, stainless inside.

[Hooli]

That's never been the person perceived wisdom on here, but if you've got anything to show that I'm happy to be corrected.
I've never had standard late downpipes off myself so just going on what others have always said over the years.

This is from a K5 Hooli. Stainless outside, stainless inside.

Thanks, that's a lot bigger gap between the skins than I would have expected too,

[Snapey]

Thanks, that's a lot bigger gap between the skins than I would have expected too,

What's got me stuffed is how they bend the two tubes.                                                   

[KiwiCol]

Hydro forming?  Nope, wrong for headers.  apparently it's done like this:

[grog]

Black Widow headers are single skin stainless, inside 39mm, guessing stockers in Snapey photo prob 10 mm less. I like exhausts to be open as possible. Anyone used them? That must give a better flow. $350 plus freight, gaskets, clamps and collector box. Pretty good buying I reckon.