4 into 2 Vs 4 into 1

750steve wrote:

loudhvx wrote: I think dual is quieter from a noise pollution testing standpoint. If you can scatter sound in more directions, any one direction will be quieter. That probably weighs in on factories using dual, in addition to the other factors.

Thats very true Lou, at our trackdays we are noise tested over here & its very hard to get a true reading of a dual exhaust bike according to noise testers. The rules state that a bike is tested at a given RPM (7000 for 600's & 5500 for 1000's) at a 45 degree angle, 50cm away from the exhaust exit height. They cant test the dual exit's correctly especially if thay are either side of the swingarm. I've seen & heard many times of a big bike passing the noise test & then being louder on track than a single pipe bike putting out similar DB. They have now started to introduce 'drive by' testing to read differently.

Interesting. So the track, I presume, is in some sort of residential area? There was a horse racing track in a nearby suburb. It was converted to a motorsports track but the noise was unbearable to the residents. It was shut down and shuttered for many years now.

Under the file base on this site you will find an artical from Cycle magazine from 1978 where 10 4 into 1 pipes are tested against each other on a KZ1000. The artical is in pdf format and broken into two downloads. kzrider.com/filebase/cat_view/231-not-model-specific?start=20 - they are on the bottom of page 2.

Though dated it is an interesting read. They did make use of a dyno and used the results of the stock bike to show what if any changes in noise, torque or power each pipe made. All of the pipes are 4 into 1 so no comparison to the 4 to 2 or 4 to 2 to 1 systems.

If you have not read it you might find it interesting.

Some are near residential areas but some are not, there are a certain amount of 'noisy days' allowed by local councils. I went to England in September & rode Oulton Park & Donnington circuits, Oulton Park's noise limit was 102DB that day (they are giving some tracks a lower DB limit than previous years, it used to be 105DB). The circuit is not near major towns or villages' & is surrounded by woodland so why it needs a noise limit this low is beyond me! Especially wen you consider it hosts 2 rounds of the British Superbikes every year.......a full on superbike is obviously quite loud!

Now, Donnington, you'll find this interesting!! Again its a huge 'park', the noise limit in my day was 112DB (a noisy day), some days are 102DB & 105DB & again the track isn't really near any built up area's......i really dont know how they arrive at these noise limits.........the bloody place hosts British Superbikes, World Superbikes AND MotoGP!!!.......the last laugh is that it's beside an airport!!

Bureaucratic bullshit i think!

Sorry for the off topic post/rant OP :lol:

gd4now wrote: Under the file base on this site you will find an artical from Cycle magazine from 1978 where 10 4 into 1 pipes are tested against each other on a KZ1000. The artical is in pdf format and broken into two downloads. kzrider.com/filebase/cat_view/231-not-model-specific?start=20 - they are on the bottom of page 2.

Though dated it is an interesting read. They did make use of a dyno and used the results of the stock bike to show what if any changes in noise, torque or power each pipe made. All of the pipes are 4 into 1 so no comparison to the 4 to 2 or 4 to 2 to 1 systems.

If you have not read it you might find it interesting.

Hiya Bruce! :lol: ........you're kinda everywhere!!

If you buy "MAC'S" Exhaust system, better inspect the pipes as soon as you get them delivered, then check for fit and finish as soon as possible. Have had a VERY BAD EXPERIENCE with Mac products, even sent them multiple e-mails....no response, NONE!!A.....oh well its Christmas will save the anger for later I will now always warn anyone about them.
If you want more detail let me know, it will take 2 pages to detail the problems I experienced.
Regards
ED

ED,

I just recently bought an '84 kz550. I was reading this thread on exhausts and thought I'd ask you specifically because you mentioned the MAC brand. I keep looking for aftermarket exhaust systems and the MAC 4-1 black chrome exhaust was the one I was going to go with. What was your bad experience with them? I'd hate to run into the same issues you did if I could avoid it.

Quite a few people here have bought mac exhausts for the 550 (me included). I don't recall seeing many posts about non-fit issues or even quality-control issues, but be aware, the macs are a pretty cheap system. The muffler is louder than stock, especially at idle, but probably more restrictive at higher RPMs. My pipes turned pretty rusty quickly. You get about what you pay for with them. Mac doesn't (or didn't back when I got mine) make chrome headers for the kz550. Only the canister was chrome.

I swapped out the mac cannister for a kerker muffler and I like that way better.


I wish Delkevic would make a system for the 550 already.

Would prefer a 4-2-1 setup with spring holding the middle together for a couple of reasons. The OG kirker I have scavenges poorly with the mid pipe being 3". Secondly it all has to come out for a oil change. Just did this Saturday.
I had a one piece unit many years ago (heavy steel) and this one (Lighter steel- thin wall)) the mid pipe is not long for this world how it claps to the main. THe less I have to release this friction joint the better.
In the end it would be nice to leave all of this mess in place for OC or at minimum just release the springs and tail section for maintenance.
Some day.... We will build some. Since no one else seems to want to.