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Aftermarket Exhaust Input Welcomed

Markuli

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It's me again everyone!

So now that my bike is running well, I'd like to change the exhaust that's on it currently. It's definitely not stock, as '79 K models came with 4-4 exhausts and this is a 4-2. It has no markings anywhere, and the end caps on the mufflers are solid sheet steel cups with holes around the perimeter. Picture a rotary dial from an old phone. I'll put up some pictures this evening when I get off work.

I'm looking for a nice 4 into 1 system, mainly because I'm into the look and sound of them. I've seen reasonably priced examples from Delkevic, Mac and CycleX which come with a header and muffler, and was wondering if anyone runs any of these and how they like them.

Another question, is there any significant performance difference between a 4-1 and a 4-2-1 (Tri- Y, like the one from CycleX)? I'm not expecting any real performance boost from a different exhaust but I also don't want to lose any power. Then there's also the performance business with megaphone tips versus cylindrical cans which I'm not familiar on at all.

I looked all over and there isn't much out there in terms of feedback for DOHC exhaust systems, especially on here so I figured I'd post up something, and maybe someone else can use this later on if this gets some traction.

Thanks for your input!
 
Tri-Y generally make more low and midrange than top end and 4-1 make more top end power all things being equal, design changes can make that overlap though.

Megaphones make more power but at the expense of noise and why the canister type is now king even though they cost a bit of power. Noise regulation is often at the racetracks now.

If the engine is truly running good as designed then you should get a roughly 10% power increase with a better exhaust.

Vance and Hines made a good one but pretty sure they've stopped now but there still may be some at some of the bigger distributors left laying around.
 
Thanks for the info AMC. That V&H sure does look nice.

I still wonder who makes these pipes, even though they're going soon.

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So after stewing over my options for the winter, I have finally decided on a 4 into 1 exhaust. The pipe is a Vance and Hines model # 14001, and is meant for a 750F. After talking with AMC, I decided it should more-or-less fit the bike and expected it to need a bracket for the slip-on.

As you can see from the pics that was pretty much the only fitment difference. The two inside headers (cylinders 2 and 3) sit a little low in the exhaust ports, eyeballed at about 2 mm low from center. I made a bracket from the old hangers off the previous exhaust, and was on my way. Since then I've also added some Lasertecs for tires.

The pipe looks and sounds awesome, and it hasn't discolored yet, but we'll see if that changes once I put in more seat time as warmer weather rolls through. Next step is a carb sync!




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That looks bitchin’! Did you need to rejet the carbs?
Although I like the look and sound of my original 4 into 4 exhaust on my custom, they are falling apart.
Right now I’m leaning towards CycleX 4 into 1 or Delkevic 4into1. I wonder if rejetting is required.



 
No rejetting needed, a re-sync is definitely needed though. AMC can chime in about the vacuum carbs not really needing any jetwork, just proper airflow.
 
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