Motad headers.

You also have Akra, Remus and the Keihans which are lovingly made in Redditch:thumby:

They all do more or less the same job so you pays your money etc.
 
My bike was the test bike for Keihan headers and they decided to keep the same dimensions as the OEM pipes and keep the balance pipe as they figure BMW spend many thousands getting the gas flow right for the motor. Keihan are a well respected exhaust manufacturer and now a thing or two about it so if they say it's needed, I'm good with that. My original set have been on for 90,000 miles and with a PC111, they make the bike much nicer to ride.

Remus don't have a balance pipe and I don't know the reason for that but they have bigger bores which I guess helps the gas flow.
 
I have the Motads. They are fine, nothing dramatically brilliant, nothing awful...

The clamps were a bit cheap so I replaced them with stainless steel Mikalor clamps. Theye are cheap compared with the likes of Keihan, so expect that to be reflected in things like clamps etc.

If I did it again, I would go for the Keihans ..
 
I have the Motads. They are fine, nothing dramatically brilliant, nothing awful...

The clamps were a bit cheap so I replaced them with stainless steel Mikalor clamps. Theye are cheap compared with the likes of Keihan, so expect that to be reflected in things like clamps etc.

If I did it again, I would go for the Keihans ..
 
I've had some

I've had Motads before, although not on my GSA. I thought they were excellent. They fitted perfectly. After several years of 'all weather' use they still looked bloody good. I'd buy again as well.

Clive:)
 
I have the Akraprovic full Ti system with stacked twin cans. It has the balance pipe and conical expansion sections to presumably create an extraction effect. My brother's bike has a full Remus system which has fatter headers all the way down but no cross pipe. Both bikes feel pretty much the same though the Remus is less noisy. The Akra isn't really usable without baffles.

The cross tube makes sense with separate silencer cans (as used on many air heads) because the flow down one side creates a suction in the opposite side (venturi ejector effect). But a 2:1 system on all 1200s already has a link where the pipes join so I can't see how the cross pipe can do anything significant.

So pay your money and take your choice. At least the cross pipe helps to protect the front of the engine from flying stones.

The Akra system is ridiculously light, looks the dog's bits and has a higher pitch rip. The Remus has a lovely straw colour with minimal greying at the head ends and has a softer growl. On balance I would have the Remus hexacone because the Akra is what it is. There is no practical way to do any work on a titanium system; any damage = new system. I got mine used so its not owing me a fortune but the Remus looks (almost) as good and is also great quality kit.
 
My limited knowledge is of Guzzis is what I was told when I bought a fatter cross section Dr John system for a tuned Guzzi (older Guzzis always had a cross pipe)..................

The cross pipe is there to aid gas flow and help low down and mid range but has a detremental affect at high revs.

The Dr John system (and the BOS system on my old GS) both had fatter headers and no cross pipe so in theory should have worked best with incresed gas flow and higher revs and lost out in the mid range / lower revs.

In reality, back out in the real world I don't suppose any of us would notice the difference between having a cross pipe or not :)

Andres
 
The old Meriden Triumphs had link pipes on those with separate silencers. Models like the Trophy with high level single sided exhaust did not have a link pipe. Did any of this actually matter in the real world?. Probably not.

The two valve per cylinder Japanese bikes (such as Yamaha XJ900/1100/1200) have the pipes joined in pairs under the engine with a cross pipe after the 2:1s then out to two silencers. This follows the same format used on performance headers for car engines though they have three 2:1 sections (one tail pipe). Very few have a cross pipes high up the headers.
 
All the histories I have read about late British twins, & airhead BMW's, made the point that the link pipe was to assist with engine silencing. The exhaust pulse goes into the silencer on both sides. I'm not an engineer, but I do know that factories tend to avoid complications & adding unnecessary parts i.e. cost, so if they took the trouble to develop the system this way, they must have seen an advantage in it.
 


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