De-cat Stock Headers

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Gents,

Anyone done the de-cat on the stock headers yet?

I like the classic lines of the bike along with the nice chrome finishing of the stock header.

I'm getting the S&S cans , DNA air filter and Booster Plug, but all info is pointing to the fact that to fully realize the performance from these parts, the header needs to be changed to the free flow type.

There are free flow headers available, made from stainless steel, but with direct contact with exhaust gas, there will be discoloration so I'm thinking that by de-cat'ng the stock header,
1. Free flow can be achieved
2. Mid ranged torque can be maintained/improved with the narrow inner pipe's diameter (34mm?)

My thoughts are that the de-cat can be done by making a small rectangular cut at the catalyzer chamber, grind off the innards, then patch it back. Obviously the cut should be done at the 'back' to keep it invisible. Got access to a professional welder (TIG) whom I think can do a good job of patching back without destroying the chrome.

Let me know your thoughts, am I on the right track?

I'm no expert, but merely gathered info by 'youtube' researching.

Thanks in advance.

 

[Roy Gavin]

I have fitted a Delcovic system without a cat on my Hima and if it makes any difference to power output it is not noticeable in normal riding.

I have found around 99% of U tube to be absolute drivel , so I would be wary of relying on anything I saw on it.

TEC and Hitchcocks in the UK can usually be depended on for something that works as advertised, I would see what they have to offer if you want an improved system.

 

[Haggisman]

I enjoy that nice smooth torque with the stock header pipes. Making the headers more free flowing may give a tiny bit more power but may alter the torque curve. Are you aware there is a restriction also in the header pipe either just in front of or behind the cat.

 

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(video by Revelry Motorcycles)
As per this screenshot, the 2 circles are where the cats are, so there is another restriction? I do know about the smaller inner pipe.

 

[_shadow_]

I have fitted a Delcovic system without a cat on my Hima and if it makes any difference to power output it is not noticeable in normal riding.

I have found around 99% of U tube to be absolute drivel , so I would be wary of relying on anything I saw on it.

TEC and Hitchcocks in the UK can usually be depended on for something that works as advertised, I would see what they have to offer if you want an improved system.

I’ve seen (in videos) the Stinger 2-1 from TEC, really good system, but not the look I’m aiming for. Hitchcocks has the free flow headers in stainless steel but without much info.

 

[Haggisman]

On the "Unofficial Royal Enfield Community Forum" someone cut out the cats on their header pipes also the restriction. I have tried to find the article about it but have not been successful yet. Maybe you should look

 

[_shadow_]

On the "Unofficial Royal Enfield Community Forum" someone cut out the cats on their header pipes also the restriction. I have tried to find the article about it but have not been successful yet. Maybe you should look

I just found the “Unofficial Royal Enfield Community Forum” and posted there as well, hopefully someone will reference it or i’ll find the thread eventually.

 

[Haggisman]

Sorry I commented on your post

 

[BurnieM]

I have a full (catless) Delkevic system with a 350mm oval muffler on my Himalayan. I also did not notice any improvement except it sounds better.
The Boosterplug did give a small improvement across the board and better gear changes.

I believe Revelry Cycles in Sydney have stainless straight thru headers for the 650.
- http://www.resydney.com.au/

 

[Fantic 125]

Hi, new to this forum, but in Australia a company called Verex make a full stainless steel 2-2 system which I think really suits the style of the bike, and sounds great with or without db killers. They have dyno results on their website (www.verex.com.au) which show approx. 10% gain in hp & torque and the air/fuel ratio when tested on a Euro 4 Interceptor with standard airfilter.
The photo's are my bike with the full Verex polished system. You can also get a brushed finish like the S&S.

 

[Yogi]

Hi, new to this forum, but in Australia a company called Verex make a full stainless steel 2-2 system which I think really suits the style of the bike, and sounds great with or without db killers. They have dyno results on their website (www.verex.com.au) which show approx. 10% gain in hp & torque and the air/fuel ratio when tested on a Euro 4 Interceptor with standard airfilter.
The photo's are my bike with the full Verex polished system. You can also get a brushed finish like the S&S.

I have a set of Verex headers (brushed stainless) on my interceptor along with S&S mufflers. I love the looks and power provided by this setup, even more appealing is the weight saved by switching from stock.