Yoshimura exhaust installed :)

[Ryedadee]

Besides almost tipping the bike over while laying underneath it, the install couldn't be easier. I was able to loosen all the nuts and bolts with my 1/4" ratchet. The primaries on the Yosh header were about 1/4" off compared to the stock. Pushing/pulling to get in place is what almost caused the bike to almost tip(yes i need stands or even better a lift). 

Pics don't do this exhaust justice. While doing my research I thought the Yoshi exhaust looked a bit out of place when looking at pics online and the same goes when I look at the pics I took. I think because of the width of the muffler it appears to be distant from the bike when being photo'd from the side. I am very happy with the way it looks and when I fired it up for the first time it was pure happiness. Low 3k rpm blips are where I find it growls the meanest and noticed the biggest difference(nice and deep). Rev matching/engine braking is just pure sex/orgasm and straight to a nap.

I will probably ride it today and then tune the FTecu and see how she goes.

If your on the fence about an exhaust......Do it Do it

[gregjet]

The theory is, that this system is one of the few exhausts that can get away with being this short. It uses the stepped header to reflect the negative pulses that was talked about very early on tin the life of this forum. Very recent engineering from Formula 1 cars.  I would be interested in a side by side comparison between this ( stepped header new engineering) and the carbon Akra ( full length old engineering) on a same dyno , on the same bike at the same period.  The one problem with it is, because it works on the first harmonic rather than a multiple ( old engineering), it won't also help at fractions of  the design rpm. Really a big rpm only design...in theory...

 

Not asking you to do that. Bit expensive. But would be very interested to hear your experience with it.

[norcal616]

@gregjet I suspect the Akra loop to put out a tiny tad more power than the Yoshi, but the biggest diffrence is the Yoshi will have a fat broad power curve rather than a peaky power curve that suits WOT... 

[gregjet]

Ok now I know I understand the new engineering even less than I thought I did. It is so secret squirrel I can't find anything on the actual calcs and design philiosphy for the stepped stuff. It's very annoying. A few pics and rough descriptions and nothing else. If I wasn't so lazy I would go and pull the base calcs apart and do some back engineering from the pics.

[norcal616]

I compared dyno charts, not the best way but it give me an idea of what the power curve looks like... 

[tavisb]

Nice. Think I'm doing the same soon. But probably stainless instead of carbon. 

[Beemer]

17 hours ago, norcal616 said:

@gregjet I suspect the Akra loop to put out a tiny tad more power than the Yoshi, but the biggest diffrence is the Yoshi will have a fat broad power curve rather than a peaky power curve that suits WOT... 

I've been under the impression that the only reason the Yosh pipe had good, low end torque like the Akra snail was due to the ECU being flash tuned and air filter being un snorkeled. What's the real deal, I'm confused.

[Ryedadee]

On 5/3/2018 at 8:02 AM, Beemer said:

I've been under the impression that the only reason the Yosh pipe had good, low end torque like the Akra snail was due to the ECU being flash tuned and air filter being un snorkeled. What's the real deal, I'm confused.

ECU flash and modding the intake will help any bike. IMO getting rid of the stock exhaust will give you a little bump in horse power along with the flash/intake but it's mainly for looks and sound. I don't think you would be able to notice a difference in power between after market exhaust systems. The difference in torque and HP would be too little. 

[Beemer]

24 minutes ago, Ryedadee said:

ECU flash and modding the intake will help any bike. IMO getting rid of the stock exhaust will give you a little bump in horse power along with the flash/intake but it's mainly for looks and sound. I don't think you would be able to notice a difference in power between after market exhaust systems. The difference in torque and HP would be too little. 

Let me rephrase that. I've been under the impression that when you go from a stock exhaust to a yosh exhaust, the exhaust alone (w/straight pipe and no ECU flash or snorkeling) you lose a little torque but you don't lose any torque when you go from stock exhaust to an Akra C.F. pipe (no other mods) due to the snail pipe it has. That's all I'm saying. I know that pipes don't add much more h.p. and the differences in torque are small so I'm not concerned with that. My concern is now I'm hearing that the Yosh pipe doesn't lose any torque so I'm wondering what the truth is.

[Ryedadee]

9 minutes ago, Beemer said:

Let me rephrase that. I've been under the impression that when you go from a stock exhaust to a yosh exhaust, the exhaust alone (w/straight pipe and no ECU flash or snorkeling) you lose a little torque but you don't lose any torque when you go from stock exhaust to an Akra C.F. pipe (no other mods) due to the snail pipe it has. That's all I'm saying. I know that pipes don't add much more h.p. and the differences in torque are small so I'm not concerned with that. My concern is now I'm hearing that the Yosh pipe doesn't lose any torque so I'm wondering what the truth is.

Get the one you think looks and sounds better. If it's the yosh and let's say it loses a bit of torque in the lower range, whatever loses it would of had will be more then made up for in the upper range as I think the shorter exhaust would be better at WOT. 

 

I chill most of the time when riding and shift between 4-7k RPM and I haven't noticed a lose in torque and I haven't remapped it yet. I'm about to do that now though 😁

[markstertt]

 I think that the stepped header is a way of making a cheaper version of the tapered header such as the Graves unit....the Yoshi and the Graves back to back is the test that I'd like to see. I have heard that the steps themselves may be part of the magic ( multiple reversion dams?) but I still like the looks of the more expensive tapered headers in titanium. However, I think the Yoshi is probably one of the best, most compact, affordable, great sounding, all around systems that works very well with Hords airbox and mapping. Proven performance that makes the same power with the DB killer installed...hard not to like but we each have our own idea of what looks and sounds right.

 

I think in actuality, there is very little difference in performance between the major players when each is tuned for...mine came with the Yoshi so the decision had already been made for me and since Hord had tuned for this exhaust...with better performance across the board...done deal.

[Beemer]

7 hours ago, Ryedadee said:

Get the one you think looks and sounds better. If it's the yosh and let's say it loses a bit of torque in the lower range, whatever loses it would of had will be more then made up for in the upper range as I think the shorter exhaust would be better at WOT. 

 

I chill most of the time when riding and shift between 4-7k RPM and I haven't noticed a lose in torque and I haven't remapped it yet. I'm about to do that now though 😁

Thanks but I'm not wanting to buy a pipe, I already have an Akra c.f. pipe. I think you misunderstood the question.

[Ryedadee]

13 hours ago, Beemer said:

Thanks but I'm not wanting to buy a pipe, I already have an Akra c.f. pipe. I think you misunderstood the question.

Ah my bad Beemer

 

Cheers

 

[gregjet]

Markstertt,

Very early in this forum's existence there was a discussion where someone posted some pics and a short article about the Formula 1 stepped headers. They are ALL doing it so I suspect the reason isn't cheapness. Being a step though, it is only going to work at a defined frequency ( and harmonics), so on a street bike, or a track bike, where broad power is needed probably not as useful. I was chasing it because I was under the mistaken idea that our bike was a 90deg firing crank, rather than a 270deg crank ( thanks to this forum I was enlightened...did I say I love this forum), mainly because I had seen the crank AND Yamaha had told me it was. Because of this, I figured the exhaust pulses would interfere with each other very badly in a 2 into 1 system. They still will with 270 deg , but not as badly. During that research I found that the MotoGP Yamahas also use stepped exhausts . Each exhaust side of 2 cyl is joined and stepped header ( unlike ordinary inline 4cyl which join the middle two and outer two). That each side of two,  is like our engine config firing order, 270 deg between .

But I agree with you that a tapered step would be preferable on a street bike to broaden the rev range that it worked at.

[norcal616]

Graves Exhaust... have on one my FJ-09... nice smooth tapered/stepped headers...

[gregjet]

That looks like the real deal. Do they make a similar one for the 07?

EDIT: just found them. Those look like SERIOUS engineering! I will research furthur.

[norcal616]

14 minutes ago, gregjet said:

That looks like the real deal. Do they make a similar one for the 07?

EDIT: just found them. Those look like SERIOUS engineering! I will research furthur.

It's my favorite exhaust of all brands I have used on road bikes...welds are XXX rated...

[gregjet]

Wish I could have bought the Graves instead of the Akra Carbons now. Should stop readin this forum.

One thing I did notice as a sideline when I was cahsing the Graves charts is how almost ALL aftermarket exhausts smooth up the 5K rpm torque dip. So besides a healthy drop in weight, another good reason to get an aftermarket system is a fatter midrange. I wonder if it is like the Suzuki 5k dip that I know is for sound test passing???