S1 headers, oxygen sensor placement

KB2WYL

CQ CQ, DE KB2WYL
Hi all. I'm finally getting serious (and the time) about giving my '07 some attention. I joined here a couple years ago when I got her, but never posted much and only did a few simple mods. I find myself coming back here again and again, so I figured it's time to start posting some of my questions. As well as offering some of my knowledge as well, can't just keep searching :)

So one of the things I'm doing right now (the bike is partially torn down while I clean and mod) is the S1 header mod. Picked up a set for 15$ + 20$ shipping. Shoot, can't beat that. Currently I'm running the PCFC fuel controller with the secondary cat delete, and the exhaust cut open, baffling removed, welded back shut mod. After that, I also enlarged the two outputs and added about 4" of 2" pipe to each. It sounds great, runs great, but of course I still have the 02 sensor hooked up.

So, when I put on the S1 headers, my plan is to weld a bung on and keep things the same, only difference being the two small primary cats will be gone. Finalimpact, I know (at least you) have done this. Should I place it exactly the same spot? Are there any advantages to going a little closer to the heads, or tail? The bike has just over 20k, so not sure how much of a difference not having the cats will make. At this point I have the controller dialed in pretty well, and usually just leave it in the stock map mode, with slight additions on the fuel at low, mid, and slightly more still at high, RPM.

Thanks very much, really. I'm taking some pics and I'll start to post some of them up. Should I just start a new thread, "20K finally rebuilding" or similar?

Loren C.
KB2WYL
2007 FZ6 (do I type in all the mods, for my avatar, in the "what bike do you have" field in settings? I couldn't find a place to add a signature.....
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Honestly unless you only sample one cylinder, the collector is the best place. Keep in mind you need it on the top half of the pipe to reduce moisture collection in the sensor. As in, don't place it where moisture can puddle or it will kill it.

If you do a search for "Bung" you'll find pictures and content.

Lets see a pic of the modified stock muffler. And maybe a before and after sound clip when you swap headers.
On mine it really helped the throttle response. But I had already advanced the ignition trigger 6.5° BTDC (11.5° total @ 1300 RPM). So I'm curious what you will discover here....





Also I nearly screwed up the angle on the bung placement as threading the sensor in has the wire mashed against the frame. It needed a little more forward angle. But its fine.


Ps use the "@" to ping another member. [MENTION=27100]KB2WYL[/MENTION]
And simply click on your name by avatar and look for menu options. Edit - then scroll down to signature.
 
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KB2WYL

CQ CQ, DE KB2WYL
I swear I don't see the option for signature..My avatar picture, my profile (likes interests etc.), email settings, blog settings....I can get to the editing pages jsut fine but I see absolutely nothing for signature. Is it just the little empty field below "custom user title"? The way it appears, that looks like it's a field for if I want to reset my "screen name". Anyhow...

Thanks for the pics, I appreciate it. One of the reasons I like this forum, I know those pics you have posted before, but it is pertinent again here in this thread. Somehow pics of my bike are lost in a file transfer I just did the other day, so I just took some now.

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So let's start at the end. Muffler looked just like all the online pics. Used an angle grinder to take out a large square. Once inside, took out seperations and tubing so that it was essentially just a resonation chamber. Pretty easy. Then, took a hole saw and drilled AROUND the two outlets. What were they, 1" each? Now I had two 2" holes instead. Welded (this was 2 years ago just starting welding) the cutout back into place. Put two 4" long pieces of steel conduit into the now 2" outlet holes. Then, put it all back together (all, as in all the plastics and everything). Here's how it ends up looking :

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Now, that muffler normally goes into our secondary CAT, right...But I didn't want all that restriction. I also didn't want to pay for one of the mid pipes. What would have good flow, and could I know would be an exact fit? Well, at your local auto store you can get one of those muffler flex pipes. One of the good ones with the braided steel outside, not one of the spiral crimped kind. Perfect, even larger diameter than the pipe so great flow, and as an added bonus to someone not paying too close of attention, it looks just like a CAT! Ha!

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Here's an even better pic. what an easy mod, takes down vibration, increase flow, look like CAT, I don't think you can lose on this one.

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So I'll try to get a sound clip tomorrow. I believe tonight is going to be just stripping and painting calipers, as well as taking the forks out for a full dump before I put Racetech springs in. I know, I could do better there. But the Racetechs in our forks, with preload adjustment caps that I also have, work alright. The sound is great right now. Even though the can is wide open, having those two 4" pipes keeps the sound a little throaty, and not too loud unless I want it to be.

Thanks again for the info on the O2. What I had been thinking was in the collector, but right where the 2 collect or closer to the mid pipe. But, looking at your pics, reminded me that the total amount of movement is only a couple of inches and as long as the sensor is downwind of the collection, whether its 2" or 4" doesn't really matter. What does, like you said, is exact placement in relation to existing parts, and vertical orientation. I'll come up with more curiosities to ask, as well as keep the pics coming as I progress. Here's one more, as she sits right this minute:

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Loren C.
KB2WYL

(manually entered so at least I can copy/paste) Bike FZ6 '07. Dual headlight mod, Preload caps on the fork tubes, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, 15T front sprocket, PCFC fuel control, Modified rearsets hard mounted, more to come!
 

KB2WYL

CQ CQ, DE KB2WYL
I'm taking more pics tonight (Usually I'm not the best with documenting things with pictures, think of it afterwards). Got the calipers painted, forks out and drained, brake line ends polished, etc etc. Before this goes too far off of "S1 header....", Is there a way to change this to a build thread? Or, should I just start a new thread? Like I said, I might have a few things where an opinion or two comes in handy, but for the most part it's just going to turn into a lot of "took this apart, put this back together".

Thanks, as always,

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, 15T front sprocket, PCFC fuel control, Modified rearsets hard mounted, more to come!
 

KB2WYL

CQ CQ, DE KB2WYL
Well...might not be either. One of the reasons I got into welding 2 years ago (besides employment opportunity/enhancement with construction) was because I've always hated having to bolt things together, and trips to the hardware store, or E-bay. Sure, there's limits, like it was way better buying the header off ebay than trying to bend the stainless and come up with the collector, ha ha. So when I started 2 years ago (mostly because I didn't know any better) I started learning TIG. Luckily I had a few guys locally to show me the ropes. Since then, and a few machines/college courses/build later, I can weld well enough to be confident in what I make, even if it still isn't as appealing as your work [MENTION=15974]FinalImpact[/MENTION] ;-)

So, when I was researching this and saw your thread, I realized that it's a pretty close call. Could work with just a little less bend coming off the heads. I thought about making a steel mount with 4 pipes sticking out that would go into the headers (go into them the same way exhaust goes into them from the motor). Mount those 4 pipes welded to a plate to something stationary and see if I can take the other end of the headers, like grab on to the collector, and bend the whole shooting match about an inch, so that on its return it stays about half inch less bent than it was in the problem area. I think this may work, as the headers being filled with pipe cant kink, and I doubt I'll kink any of the existing bends seeing as though I'll be bending them back a little, not further. Remember, I know better than to wrench on anything, especially thin stainless, just looking for a little. plenty of clearance at the ground, if I make that point half inch lower, the 90 degree bend at back will only now be, what, an inch lower. And if it puts out angles anywhere back...well shoot that's all going to be custom something anyhow. The welded stock muffler was fun, but I could and will do much better than that now. I want to get rid of all that stinkin plastic back there, but need to have a decent looking set of pipes, home made or not, before I do that. Definitely keeping my eyes open for any used pipes, but fabricating those would be fun as well, so.... :cool:

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, 15T front sprocket, PCFC fuel control, Modified rearsets hard mounted, more to come!
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
I'd never tig'd aluminum before that night but it was pretty easy. Though the steel much easier. Given the two and if you have the equipment, grind the hump off the pan and weld it up. Or grab an S1 pan.

I say this because bending the header without heat could lead to cracking later at the collector unless you can keep the pressure off the collector. That said if you are going to bend it, you may as well bend it twice and point the outlet straight up for easy fitting to tail pipe/muffler.

Have fun!
 

KB2WYL

CQ CQ, DE KB2WYL
You know, [MENTION=15974]FinalImpact[/MENTION], I was wondering if the sump was solid AL or cast. Most engine parts are cast AL, which even for an experienced TIG'r can be a challenge. Cast metals LOVE to soak up (well, oil in this case), and as you know TIGing anything is a great way to find out whether you have 2 oil molecules somewhere ha ha. If, on the other hand, the sump is cut from block, or punched, then yeah a little cleaning up and it's an easy TIG. I don't like welding on cast (aluminum at least). 5356 Rod does a pretty decent job on most of it, but.....

I was looking last night, and that nub is at the back of the sump. I thought it was front. This being the case, I'm thinking I will be able to bend it. If we think of the two bends coming off the motor as 60 degrees and 60 degrees (to get down to the sump area, horizontal part of header), then I would only need to change it to about 60.2 and 60.2 degrees. Little stress. As for the second bend, to point the outlet straight up, I don't think I'll have to with my mid pipe being what it is, a flex pipe connection. But, we'll see.

Last night got the new springs etc. into the forks, forks on bike, calipers and new brakes on, and little bit of the plastic back on so that I could start to figure out the lights. Making progress for sure. I might even take the day to work on it. Usually I only work at night, after actual paying work ha ha.

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Loren C.
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Fwiw I cleaned the pan repeatedly with MAF cleaner, baked it at 300°F and cleaned it again never touching it with items used on steel or anything else. Yes, cast is harder to weld but using best practice helps...

As for bending the header, bending a little up front will have huge effect out back. It certainly won't be a 1:1 ratio!

Needless to say our path is not so different as the whole front is off the bike, needs a new tire, forks are due for drain and fill, and lighting needs installed...
 

KB2WYL

CQ CQ, DE KB2WYL
Ha!. That's funny because I was just thinking as i was bolting it all back up how I've been meaning to do the fork swap. I had the springs, so I wanted to give them a try, but a few months down the road maybe I'll take it all back apart again. I'm sure the painted calipers will only last so long until they get some dings anyhow. Maybe next time I'll do it right and disassemble them fully, do a powdercoat. One of the things I've been meaning to get to finish off the tool lineup, powdercoating setup. I just replaced to oven in the house at X-mas, and the old one still works, that's a good excuse to get a powder coating gun right??

As for bending the header, I suppose I didn't explain very well. Agreed, a small bend up front will give a huge effect out back. So, if I have the headers filled with steel tubes from the inlets to the first bend, then they cant bend there. The bend would then come out in the first two angles that the exhaust encounters, which are both about, what, 60 degrees or so. That's what I meant by, if I can put just the slightest bend, make them 60 point 1 degrees each, might be enough to get that clearance.

If not, then yes best practices on the TIG cleaning.

Well gotta go, fan clutch on the Ford ranger waiting for me...UUghhh!!

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, 15T front sprocket, Speedo healer, PCFC fuel control, Modified rearsets hard mounted, more to come!
 

KB2WYL

CQ CQ, DE KB2WYL
Well...Almost there. When she's all back together, I'll do the recording. Then, on to the headers. Have been having intermittent issue I thought was the clutch switch. Little search here on the forums yielded info that it was actually the on/off switch. Heck with that noise, soldered it "on". Cleaning would have worked as well, but would have required future attention. That, and the way these bikes are wired, with that 12V having to come all the way up to the switch and then all the way back mid-bike, I figured any extra resistance from the switch to be something it was good to live without. Sure enough, after solder, even the fuel pump priming, and starting the bike, sound smoother than before. Glad I did this little one:

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Starting to look like a properly cared for bike again. The rainy season here can really take it's toll:

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Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, 15T front sprocket, Speedo healer, PCFC fuel control, Modified rearsets hard mounted, on/off switch solder disable, more to come!
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Do it! The little PC guns are cheap too. When I PC components I bead blast first, blow the chunks off, then wipe with Acetone, apply powder and into the oven it goes. Then use a laser thermometer to track component temperature. The products used want the part at 400°F for 15min. So you start the timer when the part hits 400, not the oven.

I did the rear sets three seasons ago and boots haven't worn through yet. Its good stuff!

I'll warn you tho - there is a supplier out there that sells PC called Yamaha Black. It is so far from black metalic its more Brown and waaaaaaaay too much sparkle in the metallic. I listed PN in a thread somewhere...
 

KB2WYL

CQ CQ, DE KB2WYL
Well well well...It's late, and I don't have much time. Welding class tomorrow morning, early, and I am going to take the bike for a test drive.

First, the bad news: The wife was taking a nap today, and so no recording of how the exhaust sounded with the primary cats still in. Bummer.

But now, the good news: I did it, and without even touching the S1 headers :). Took it all off, compared. REalized that it was going to take 4-5 hours. I only had 3 or 4 hours. What to do....Well, I figured, I have two pairs of headers, and worst case scenario is that I have to modify the S1 headers. But, since that was the plan anyhow, why not try cutting into the stock headers? I kind of like the fact that even though the 90 is a little more severe, there is also a lot more volume total because of the 2 cat areas. If I could clear the cats out, it would have to at least be AS GOOD as the S1 headers....So, here's the pics. No time for individual explanation right this second, but I'm sure you get the picture. If you can weld, this is not hard people. Total cost was 1 bandsaw blade from Harbor Freight (lasted right til the end of the cut, perfect), so, $7.99. Saw in half the header, halfway through the cats. This gets half of the cats to just fall out. Put the header side of your two piece muffler, now, in the vise. Use whatever you wish (I used deburring grinder) to clear out the rest of cat from this half. Clean, clean, clean. I used wire grinder, sanding block, then wash and dry. Set back the way it was, and start welding. See how my weld isn't completely uniform? Lots of starts and stops, constantly changing positions, so that warpage doesn't get you. Tadaa! cat-less S2 headers! I'm not sure, but I haven't seen anyone else do this yet (I'm sure someone has, but I haven't seen it). Back on bike, ready to ride. [MENTION=15974]FinalImpact[/MENTION], thanks so much for the likes and replys. I WILL get a recording of her now, so at least people can hear how good you can have this bike sounding, and how well you can have it flowing, all for free (if you have a good bandsaw blade, ha ha).

Here's the pics from tonight's operation:

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Thanks again!

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, Stock header cut in half, cat's removed and welded back together, 15T front sprocket, Speedo healer, PCFC fuel control, Modified rearsets hard mounted, on/off switch solder disable, more to come!
 

KB2WYL

CQ CQ, DE KB2WYL
On the way out to school...I'm stoked to give her a ride. I think this is great info. [MENTION=15974]FinalImpact[/MENTION], between your mod with the S1 and mine with the S2 headers, we've got some great options for giving the bikes breathability. Even if one doesn't weld, someone locally does, and whether mount and bung, or welding two halves back together, total cost of project would still be under $100 :)

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, Stock header cut in half, cat's removed and welded back together, 15T front sprocket, Speedo healer, PCFC fuel control, Modified rearsets hard mounted, on/off switch solder disable, more to come!
 

FinalImpact

2 Da Street, Knobs R Gone
Site Supporter
Not that I'm some flow expert but allowing the gasses to expand decreases velocity. Then they have to be compressed to exit. That pressure wave hurts the flow worse than a sharp bend.
The ideal thing would be a tube or filler so the gasses are not allowed to expand and they keep their velocity up.

You could weld it in in 4 spots like the oem cats are welded in from the outside....

Band saw blade #2?

Edit: in addition, the expansion allows the gasses to cool which also impairs the scavenge effect of the collectors. Id like to see a solidworks flow model but it would be hard to do an engine with its valves pulsing into the tubes and collectors and get an accurate simulation as the gasses leave the head at roughly 12##°F and loose heat through every transition.

A prediction is it may make it sound a bit raspy at lower rpms.
 
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KB2WYL

CQ CQ, DE KB2WYL
"you murdered the..."

Well, if I don't go someplace else first, riding the way I was today :eek: Seriously, what a difference. When I did the secondary cat, small diff, slightly better sound. Drilled them out, again. Cut the muffler open, better sound, very little performance increase. But doing this...man, high RPM is a brave new world ;-)

So, as for your comments about the flow. You're right, expansion slows down flow, decreases scavenging effect due to decreased temp. But, at higher RPM, where this really matters, that expansion chamber, I think, is still only slightly more volume than the two pipes entering it. I wouldn't be surprised if, those two cylinders dumping into that one collection chamber, the cooling effect is not too great. I'm sure you know more than I about the physics of it (shoot my solidworks experience is limited to 3D models ha ha), but I would think the effect is limited by the short length of the expansions.

It's all about the waves, right? ;-) So, if those two (now larger without catalyst material) areas are shorter than one wavelength, they probably have very little effect. This would mean that the higher the RPM's, the shorter the wavelengths, and the more it could have a negative effect. Bummer, right where you need it. But again, trials today indicated that the gains in flow far, far outweighed any backpressure created from these effects. In any case, it's definitely less than those old crusty cats were creating!

I almost put a straight pipe through there too! As a backer for my weld. But when I started in on it and the weld was going so well, I just kept on with it and didn't think about it again. Bandsaw blade? Ha! That's funny, and will probably ring true at some point he he he.

I have to make a recording, and I will. It is not tinny. It was, a little, with just the muffler drilled. Then, it was still when I opened up the muffler and gutted it. Now, with everything open, all diameters are still small enough to keep it neutral. Low RPM, I'd say that's best description, neutral. Like a lot of the cans sound with DB killers. Mid range, again. High RPM, it really starts to open up and get loud, and sounds good. Though now I wonder if some of the increased volume, high rpm, is that wavelength folding back on itself effect....

Interesting stuff! I'm going to delve into the timing next. I really, really like where she's at, so probably start with .05" or so, somewhere around 3.25 degrees, see how that goes. Rains supposed to be back for the next week anyway....siiiighhh...

Thanks again, good stuff!

Loren C.
KB2WYL
'07 FZ6. Dual headlight mod, Preload caps on the fork tubes, Racetech fork springs, Airbox mod, AIS block off, K&N filter, De-cat mid-pipe, OEM muffler gutted completely hollow with dual 2" exits, Stock header cut in half, cat's removed and welded back together, 15T front sprocket, Speedo healer, PCFC fuel control, Modified rearsets hard mounted, on/off switch solder disable, Gel Pad Yamaha seat, more to come!
 
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