MAC/Yoshimura exhaust systems.

There is desperate and than there is desperate and I am not at the point of installing a stock exhaust on an engine that I paid $675 for hadwelded and regrounded cams and another $1000 on a custom 1400 kit. I still have a D&G 6-1 pipe but a Yoshi stile pipe would be killer.

otakar wrote:

I have become a thorn in the side of MAC Performance. I seam to call them or email them almost every day now. I am doing my best to convince them to reproduce the series I Yoshi pipe. I don't know why but I think that I might be making headway. If any of you have any ideas or ideas on how to convince them that reproducing the pipe would be the best idea they ever had and the best decision they ever made, I believe they should be made aware of it, and MIGHT be convinced to listen to us. I also understand that they make an effort and view this thread on a regular basis. SO WHAT I AM SAYING IS FOR YOU GUYS TO LET YOUR THOUGHTS BE KNOWN.

if i understand this thread correctly, the series 1 is the 1 everyone loves. I have to assume it is for looks alone, since the pipe doesn’t perform well. it is the pipe that Mac said is a drag pipe. it is also the pipe that failed the 78 Motorcycle Mag., Pipe shoot out.

I'm not trying to start anything here, just repeating what i have read hear. Personally, i would always pick a Kerker for looks, and the added performance is a bonus .

The series I IS the one that we all like and is a HI revving pipe. It kicks in at about 7500Revs this can be tuned by putting in arestrictor into the collector area.

Series I

Series I

Series I. Its is not just looks it is also the sound of the Yoshi, it sounds very crisp and clean until it hits the the tuned RPM than it snarls. What I don't like about the Kerker (I had 3 of them) is the sound and the fact that it is so loud. There is a picture of a Bassani pipe in one of these threads that shows a restrictor in the collector. That restrictor makes it more responsive in mid range. MAC would tune this pipe for treatable midrange.

The problem the Yoshi had was that it had too much flow for the street. on stock cams. Once you match the exhaust to the cams everything changes. The article compared a particular bike with stock cams. I can try to look up what bike and engine the pipe was tested on.

OK the pipes were tested on a 1978 KZ1000. The article also states that the pipe was the quietest out of all that wer tested and there was NO SOUND SUPPRESSION around the baffle. This means that all the sound is muffled BY THE BAFFLE. this mens that there is very high flow threw the collector and all the flow is eventually stopped by the baffle. This equals a lot of back pressure, until the baffle is removed. This also means that the flow can be tuned with the right restrictor and the right baffle size.

well i guess we just need to do another shoot out with a better motor and dif baffles.:woohoo:
wouldn't that be sweet.
it would be interesting if we had the dimensions of each pipe so u could try to draw a conclusion to why each pipe performs the way it does, in that shoot out. this was why i started my header post. i want to try and collect all of the dimensions i can.

That would be sweet. I have always wanted to test a variety of pipes pipes on a modern dyno. Anyone got a dyno??

The problem is that all the pipe makers are discontinuing pipes for our bikes with the exception of MAC, who actually is coming out with new models. But what is sweet about the is that most of the bases will be covered by one maker. SWeeeeeeeeett

otakar wrote:

The problem is that all the pipe makers are discontinuing pipes for our bikes with the exception of MAC, who actually is coming out with new models. But what is sweet about the is that most of the bases will be covered by one maker. SWeeeeeeeeett

And who's factory is 6 miles from my house!

otakar wrote:

The problem the Yoshi had was that it had too much flow for the street. on stock cams. Once you match the exhaust to the cams everything changes. The article compared a particular bike with stock cams. I can try to look up what bike and engine the pipe was tested on.

I'm very interested to see how it works with my combo, I haven't heard of a yosh series 1 on a ported 810 yet.