Yoshiumira KZ Exhaust: Measurements anyone????

Try to remember regarding the "mid range" issues... The Yoshi was originally intended for a racing engine and for the most part was designed for WOT... Not necessarily for the everyday riden low to mid range operation...

That's the beauty of designing your own "TUNED" exhaust... Designed and built for where your steering the maximum power band rpm range your desiring.

Example, pending your engine build... As in my case, the cam selections I chose are designed for low to mid range power... Sure, they operate as well as WOT but the mid range is where she truly pulls you off the bike... :woohoo:

With that said, the design of the exhaust should also compliment the build where the power band is mid range as well... 3k - 5Krpm (50 - 70mph)...

Here's a couple examples of some calculators I have found... There is a science to this after all....

OMR

No eBay APP ID and/or Cert ID defined in Kunena configurationHEY OMR......

this guy has one someone made....honda ---but same concept...it retains the flow ok imo....a little thick on the metals and a tad under the quality and finess from what i can see...but better than many attempts i bet...not bad really......maybe he knows some background on who learned enough to make this pipe...contact him for info and see...maybe the welder/fabber...has made kz's too...

might share his notes.. lessons learned...mistakes...suppliers ect.....cheers

Hell for under $300, I'd buy one from him as well...

If this is the same guy we've seen before, he only does Honda Yosh reproductions, no KZ's...

Still cool as hell if you ask me... But hey, what do I know.... :laugh:

Thanks Craiggy...

Like I said before, start out with an existing header and bend your own tail pipe.

otakar wrote:

Like I said before, start out with an existing header and bend your own tail pipe.

That would certainly be easier, no argument there, but where's the fun in that? That's just like telling someone to buy a bike instead of building it. Sure it's difficult, time consuming and takes a myriad of skills, some of which you may not possess. But that's what makes it fun! (To me anyway) challenging yourself to learn something new or do something different. That's what I would get out of it anyway

Hey OMR, do you think a tubing roller like this might make it easier to make those nice, sweeping primary tube bends ala Series I Yosh? I just got this from H.F. with a coupon for $140 out the door. It comes with 1", 1.5" and 2" dies to! The piece of tubing in the roller is a 1" test piece, to give you an idea of the size. For a H.F. tool, it's better made than I would normaly expect from them. If you're interested I can email you the coupon

Hey Porche... Thanks for the offer... I have a HFT 2 miles from home so I'm coupon-ed as well....

I had been eye balling their roller as well.... One thing got me thinking about the curved design though is front tire heat... Still debating it...

But I sure luv the way it looks...

OMR

Here is my first attempt with a 1" test piece-

I set it under the Series II Yosh header I have so you can better visualize how far the constant radius curve sticks out past the Yosh primary tubes.

There is so much room to play with things though- instead of the single tighter radius I put in after the exhaust port, you could put a longer, larger radius in, then flaten out the main constant curve in the primary, then tightening up the radius a bit into the collector. The options are infinate

Adam, if you end up building yosh style constant radius pipes you're gonna become very popular!

Before I wasted a lot of time and money on a constant radius pipe,I would spend a little time with someone who knows flow characteristics of a Kawi head and see what ur getting into--like Mr.Cavan.Seems to me that such a pipe would move the power band way up the rpm range to where for us average riders it would be a damn nuisance.Just my 2 centavos.bj

You are absolutely correct, there are many variables at play in a correctly designed and tuned exhaust system. This is OMR's thread though, and I believe he has had many conversations with Larry C. regarding custom header construction. But I'll let him confirm or deny his knowledge/research on the subject