Don't know where to start rambling so I will start by saying why change the exhaust? The bike has plenty of power as it is. Heard all the stories pros and cons of stock, slip ons or full system. Let me tell you if you try to justify any reason for keeping the stock or going slip ons don't bother. I wanted quiet, thought the power was enough, wasn't bothered by the heat or weight didn't want to spend the money. Then there was slip ons removes the cat in the exhaust loses weight frees up the back pressure. Then theres the full system loses most weight gains most top end hp. So which one is best? Compared all horse power dyno charts for all three and it seemed that slip ons gain a little all the way through the rev range and are easy to install could be more of an impulse choice. With a full system it seemed you would loose bottom end power and gain mid and top end.
Well I had to ask myself which one I really wanted a full system won over for a couple of reasons. Chose the Yosh for their dyno results of smoothest power curve good quality and quiet exhaust note. I thought it would be loud still and lose all my bottom end 3200 and lower. Well I got done today and holy sh*t everything was better than I had hoped. Throttle smooth and crisp right from the bottom no loss in torque (have the quiet baffle in). Power everywhere what was I thinking not doing this sooner. It seems to me that this bike was designed for this pipe and Kaw was forced to install the other for emissions - obviously. I like everything about it 90 degrees out and it has more power everywhere than when cooler out! The handling is smoother and crisper. Chain maintenance is so much better. So If your thinking about slip ons skip it or stock chuck it there doesn't seem to be any down side to the full system. I don't even have a map loaded for it yet. Love this bike more than ever.

* Last updated by: bgordon on 7/17/2009 @ 7:53 AM *

I was reading and reading and bam! You tapped on the preset and loved it. You sucked me in with the cat and then BAM! Slowly I turned, 4-into-1 pocket is find the side cutters....

I picked my Full Yosh for the same reason. What an amazing differnce in power and it is not loud at all. I gained HP everywhere and fuel milage went up. Now go get a custom map and take advantage of the power to be had...

Before and after dyno curve

Hoopie,

Run, do not walk, to the nearest qualified tuner and hand them your credit card. You will be glad you did. I was absolutely floored by the difference on my '07 ZX with the Yoshi 4:1. To be fair, I had to replace one of the throttle bodies due to a fly pulling snafu, and as a result my throttle bodies needed to be sync'd, which I had the guy do first. Oh, and he pulled the sound reducing butt plug out of the Yoshi muffler too. So maybe some of the difference I saw was from those two things.

But DAMN, what a difference! The TBs being out of sync caused a VERY slight flat spot right off idle. Driving around town, this made the bike feel really heavy on slow 90 degree right hand turns. (Not so much on left since you don't generally slow down as much.) Between the sync and tune, that flat spot went away. The bike literally feels 100 pounds lighter when riding slowly around town!

Without the sound cone plug thing, the Yosh really barks when I open her up. Not too loud at all, but it sounds really, really mean.

Shameless plug for those in the DFW area. Dean, up at MetricTech in McKinney did my tune, and I recommend him without hesitation. Good guy, and he knows what he's doing. I didn't know him previously, but apparently he used to be the service manager at Central Yamaha.

-Matt

matttheheat
mine has been custom tuned. I think you meant Kankow.

Thanks for the input the custom tune is probably the way to go. Hey Rook better get one yourself.

I've been thinking of getting the Yosh Full, but I'm also thinking of getting the PC V & auto tune, does the Yosh come w/ an O2 sensor bung or would my dealer be able to put one in? (Not sure how this sort of thing is done)

Thanks,
-Dennis

Nope, doesn't come with the bung.

-Matt

Nice choice of pipe Kaw....I'm running a polished stainless system on my busa.....love the hell outta it, great power, looks, lost a ton of weight, quiet enough for long rides and passengers, and got it for a killer sale price

Thanks Bad took a 5 hr ride today and confirmed my thoughts about the pipe. Yeah all the same with mine great deal power weight loss quiet. Was out by the coast on a straight cool weather in the sixties slowed down and railed on in first it rode the front all the way. On another part got on to redline through a couple gears and looked down saw buck fifty in pretty short order so smooth going through the gears. I was shocked how quick to attain the speed. This bike really is riding satisfaction just mile after mile even cruising on the highway ain't so bad.

I asked Mickey Cohen, the guy who sometime back was #1 team mechanic for Suzu, what is the quietest exhaust for good power..... ?

Yoshimura, was his response.

I use to go to school with his son in Yokohama in the 60's.! we drank a lot of beer in Shijiku.

My full Yoshi is almost as quiet as OEM. Very nice.

My OEM exhaust was about as quiet as my honey, half asleep, and waking and moaning to getting off to head.... LOL

I suprised myself today, changing things around with the guages, windscreen, top-tree mount.... I'll post up some b-tween pics l8tr.

* Last updated by: JDC on 7/18/2009 @ 10:01 PM *

The Leo Vince comes with (2) bung holes (2 different sizes, AFR & EGT). Similar in design to the Yosh.
This ones ceramic coated inside & out. It's actually quieter than my previous 2 Bros slip-ons even without the db killer.

cycye,

That's a nice looking bike!

Thanks JDC.

Here's some real sexy exhaust... I know, I off topic now...

1976 CB400F... Brand new Kaz Yoshima 4-1... never installed

Gotta like a good bung hole for sure. They can be handy for auto tuning, right?

bung hole??? i need tp for my bung hole!!!

haha! glad somebody else figured out what i did a couple months ago! nice pipes guys!

Glad you guys have had good luck with Yoshimura, different story here. The Yoshi slips on my 14 rattled and buzzed from day one. They had welded the quiet inserts in place and I had to Dremel 'em out but that finally got rid of the buzz and brought in some more mid to topend.

I bought the 4-2-1 full system for my CBR and it has been a nightmare. A real PITA, nothing lined up, have had the pipe off twice now, first time crushed an exhaust gasket due to misalignment and I had an exhaust leak. Second time was this last weekend, we tried to align the exhaust flanges on a granite surface table out in the machine shop and they just wouldn't line up. I got it back on there after several hours of struggling with it and will do a soap bubble test tomorrow to check for exhaust leaks. If it does, it's going back to Yoshi. Only marginally lighter than stock, about 5 1/2 pounds.

Sounds OK but I can't really find the power yet. There's a bit of a flat spot at 4000 rpm, running the DynoJet Yoshi full system Map M125-006.

The system looks good but right now I'm not very happy.

Kruz

* Last updated by: Kruz on 7/20/2009 @ 3:30 PM *

Hey Big K, I've installed my share of exhausts on bikes, so it wasn't a big deal to me, but I had a fairly major fitment prob with my busa yosh header. I sent it back because I got it on and working, but the fit was unacceptable. They sent me a prepaid shipping label that I printed out, I stuck the header in the original box and back it went. They got it, and while trying to align it on their busa jig they damaged it, so they aligned another and sent it back to me. I had to line this one up just like the first, and take a rubber mallet and a piece of 2x4, and tap the 3rd headpipe to get it to line up. Once I did tho, it fits much better overall than the first header, and the main underbike bracket lines up like it should. But I could easily see somebody with less experience mangling their shiny new stainless pipe trying to get it to fit. One nice thing about the pipes tho, is at least on my busa, they come with seperate spigots that bolt to the engine, then the header pipes just slip over those and are held on with springs. VERY nice design....you're guaranteed to get a solid leak free fit with the spigots, and its much easier to remove/install the head-pipes. Plus the head pipes don't have to be perfect to be leak-free. Overall I have to give them a D on fit tho, but an A+ on customer service and getting things corrected fast and easy, with not a penny out of my pocket. I didn't even have to leave my house to send the header out....UPS came to me I also give them an A+ on looks, and an A+ on power and delivery. The best way I've found to line up stubborn pipes is to fit and hook the springs up to the headpipes that line up, then take a piece of wood wrapped in a rag, and use a rubber mallet to tap the headpipes that don't line up into place. It doesn't take hard taps...just a couple, then check, a couple more, check etc till they slide in. Its actually pretty easy to do. Watch out for trying to line it up off the bike, much harder and much more likely to damage your shiney new header. I wish I was there to help J, I've got fitting stubborn headers down to an art lol. If you aren't easily able to get it right tho, send it back and let them fix or destroy it....not you They were super quick and easy to deal with on my header probs

* Last updated by: BadinBlack on 7/21/2009 @ 5:46 AM *

Wow, great write up there B in B, you nailed exactly what I just went through. I used to be a pipe builder, right out of high school I did an apprenticeship for a pipe builder named John Easton down in Houston. We built a lot of two stroke stuff, expansion chambers and also four stroke stuff. Among our clientele was some big name AMA racers. Anyway I did a 3 year tour of duty there before heading off to college. The reason I mention it is we had an occasional ill fitting pipe that didn't quite lay into the tooling fixture just right. This seems to be a problem with Yoshimura of late. This thing was a real bastich, I was expecting a precision fit for my $900 and what I got was only parkpark close.
The first time I did the install by myself and 3 holes lined up decent with #2 way off. I did some tapping with a rubber tipped persuader but no luck. I picked up some new gaskets last Friday and had the guy that runs our engine build shop help me with the install. First thing we did was to take the pipe completely apart and polish every slip joint and then liberally coated everything with copper based anti-sieze compound for a slippery fit. We lined up #2 through #4 pretty good this time but #1 had to be forced into alignment while I held it there and he tightened it up. It's not perfect but it may seal OK. I'll do the soap bubble check to look for leaks and if it's OK, I ain't taking these back off fer nuthin. If they leak, they're going back to Yoshi for a new set. As it stands right now I would not buy these pipes again. You were being kind giving them a D for fit, I'd say D- or F+ tops. I don't need this kind of aggravation in my life right now....they do look great though and have a nice sound.

Kruz

* Last updated by: Kruz on 7/21/2009 @ 7:22 AM *

i thought the yoshi headers didn't need the gaskets? or is that just for the 14? i think everybody goes through a little frustration, but the end result should be worth the hassle.

kawnow wrote:

Thanks for the input the custom tune is probably the way to go. Hey Rook better get one yourself.

don't get me confused now, guys.

Hey B in B, what color are your headers where they leave the cylinder? Mine turned blue at the cylinder end and then fade to a golden color by the midpipe. I ran the stock ECU for about 3 days until I could get the Power Commander on there and get remapped so I was probably running a touch lean at first.

Kruz

Well, I finally hammered this thing to the redline and it's sick.....and I don't mean that in the good way. Right when this thing outta start to really flat boogy it just goes flat and then I got a loud BRappppp like a backfire right before redline. Something in this pipe or mapping is off... it sounds like crap. I'm bummed, I feel like I've ruined an awesome bike..... and wasted almost $1300 to do it. Yoshimura didn't supply an A/F bung so the pipe would have to come back off again and go to the weld shop to have a bung installed ....just so I could have a custom map created on the dyno. If I take it back off, that's another set of gaskets, another full day fighting this thing....and I still don't know if I have an exhaust leak. This pipe is junk, I'm ready to throw in the towel and put the stock exhaust back on...this is turning into never ending aggravation. I'm glad some of you guys have had good luck with them but Yoshimura, you got my last dollar......ever!

Kruz

* Last updated by: Kruz on 7/22/2009 @ 7:01 AM *

Kruz:

Wondering if you have contacted or are planning to contact Yoshimura about this. Something is very wrong. It would be good to know if their tech/customer support is any good... -bg

Hi Bill, I just got off the phone with a friend who had the same problem on his CBR 600RR with Yoshi full system and he said customer service at Yoshimura was very good, they drop shipped him a new pipe. Bad in Black had the same experience with his Busa pipe so this is no rare occurrence but he said the same thing about Yoshi's customer support. I'm trying to get ready for a company trip to the Airventure 2009 Airshow at Oshkosh, Wisconsin so I'll be gone for the next 12 days and won't have time to deal with any of this. I was hoping to come back to a good running machine but it's not going to happen. I will call Yoshimura and talk to support and also DynoJet and see what they think. At this stage, I might just take the bike to a DynoJet Center, have them weld on an O2 bung and install a new pipe from Yoshi then create a custom map. I'm tired of messing with it, very discouraging when you spend good money and the stuff doesn't work as advertised. There is no other way out of this I'm afraid, too much money into it now to go back to stock.

Kruz