Wide-band Lambda AFR reverse SuperTrapp tuning and FAQ confirmation

[kz550]

As the SuperTrapp FAQ recommends, you should alter the number of exhaust diffusers, ride and determine if performance is more or less to your liking. Well, I now have a tool to take the guesswork out of the equation, confirm riding impressions, but arrive at the same desired result. This time, there's no arbitrary seat-of-the-pants impressions that could go either way. A wide-band Lambda sensor will give me 100% absolute real-time air to fuel ratio numbers to tell me how well I've tuned my Supertrapp and thus, my carburetors.

The AEM wide-band Lambda AFR digital readout and O2 sensor (30-4110*) was installed last year on my 900 Ninja (ZX-9R). I recorded many of the results over a variety of riding conditions. Last years readings however were on a different motor, running different engine coolant. Since it was cheaper to swap to a younger motor than to even replace the oil seals in my 128,000 mile motor, I now have a much lower mileage motor, but also running waterless engine coolant.

The combination of light oil leakage fouled my original AEM O2 sensor and eventually burned out the digital Lambda readout. One warranty replacement later, it's all working again and I have new numbers, different from before even though my carburetor jetting is mostly unchanged from before. I've confirmed my mid-range jetting is too lean, 15.2:1 lean at 55 MPH. Conventional SuperTrapp FAQ wisdom says to remove one or two diffuser plates to boost performance, get the AFR back below 14.7:1. Only this time, when I do, the AFR readout will tell me how much closer I am to ideal. My plan is to tune either only my SuperTrapp and/or my mid-range jet needle height to arrive at more ideal AFR numbers that I was seeing from the bike last year.

For those wondering or a bit puzzled about how an AFR readout got on a carburetted motorcycle, it's aftermarket.




* 30-4110 is the full kit. The cheaper 30-4110NS version stands for No Sensor, as in no O2 sensor.

[kz550]

When it contributes 5% to the gap of combined diffusers with a closed end-cap, it's enough to drop AFR on my 899cc sportbike as follows:

I don't know how to calculate surface area, so I'm just going with a numeric factor of the combined diffuser gap. AFR is about 0.2 lower up to 3K RPM, 0.3 lower at 3.8K/55 MPH and 0.5 lower at 4.7K/72 MPH.

Once it's safe for an interstate tank run, I'll know more about how this translates. I have some numbers recorded from last month for a baseline to compare to. And I was already satisfied with mid-range oomph, but it feels like there's a little bit more. If that's just in my head, it did seem like I made a mental bookmark of how the bike pulled, lighted the front wheel. I don't remember it doing that prior to tonight.

[kz550]

Circumstantial riding last week. Got a wild hair after fueling in a couple gallons. Told myself that it was okay to put some miles on the bike up into the nearby mountains, just go easy, lean the bike, but take it smooth and slow. Noticed a car about a mile up ahead at the base of the mountain, waiting. Thought I was going to get lucky and they'd wait for me to come by them for whatever they were waiting for and I'd hit the jackpot on some clear sailing. Turned out to be two cars, a Suburu WRX (turbo?) and the lead vehicle looked to be an Audi of some sort (A4/A6), they pulled out in front of me conveniently. They were definitely going to hotrod up the mountain as a pair and since I was the last vehicle for a while that had gone by, they had a lot of room up ahead to play.

Here we go. :no :evil: (my own worst enemy)

Yes, I wanted to see what they had. I let them race into the first curve, while I held back. If they were really fast, I'd have my own room to play, but if they were slow, it was going to suck. The Audi braked into the corner, so he was pushing and actually appeared to come out of the corner pretty fast. I'm sure in their cars they probably felt like they were pulling some Gs and they thought they were going to dust the green sportbike. No way to tell until I dropped a knee down into the corner myself to find out.

I made up several hundreds of yards on them in the first two corners and was already on the tail of the trailing WRX going into the third corner. He had to of seen me flying up behind him, b/c he gunned it going into a RH sweeper before a parabolic 25 MPH LH corner. He must have been beyond his comfort level though, b/c he was well over the centerline, sliding and throwing back a cloud of dust and debris at me, so I slowed and veered to the outside to avoid. They continued on and were making good time in the next faster 30 MPH corners, but up ahead was another series of 25s. I was only catching them a little in the 30 MPH corners, but I was all over them like a cheap suit when we got to the 25s. They were belching out a lot of black smoke and you could hear their engines whining and thumping along. There was every indication they were trying to run. Try as they did, it just wasn't working out how they probably envisioned after jumping in front of me.

I was just carrying my energy through the corners in a fluid motion, lugging the bike around in 6th gear. The WRX must have gone in too hot or missed a gear on the second 25 MPH LH'er, b/c he lost a lot of momentum. I had to panic brake to avoid running into the back of him. Couldn't understand why they were going in so fast and parking it in the corners.

Up ahead was slower traffic so I slowed to 50 MPH to let them as a pack move ahead, giving some spacing so I could have some fun in between catching back up to them. When I rolled on the throttle WFO I was probably at about 6,500' AMSL, the AFR went into the low 10s and the bike struggled to accelerate. :-k Rolling off a little brought the AFR up a little again and the bike lunged forward. Sounds like my mains are still too rich on average for the new engine and where I typically ride. I did my corners at my pace and caught back up to them about 1/4 mile ahead. The slower vehicles all moved out of the way and it was just us three and hopefully clear sailing. Again I let them take a sizeable lead, before turning up the pace going into the next sweeping corner. I began to get the impression they weren't good drivers, just kids who dumped a reasonable amount of money into their lowered cars, but sorely lacking in their driving skills & confidence. I could catch them at-will, which was turning out to be somewhat fun, somewhat aggravating. They'd accelerate to about 90 MPH on the straights and I'd stay down at about 55 to let them go, then as they'd hit the corners up ahead, I'd accelerate, take the corner without slowing, carry more speed into the next, reel them in at somewhat of an alarming rate and repeat the yo-yo.

Having had my fun, point made, I turned around midway up. I think that was another fateful decision, b/c about two miles behind us was a state trooper coming up. He wasn't going terribly fast and I doubt he saw any of our dumb foolery, but I played it cool going back down and kept checking behind me to see if maybe he knew more than I thought and had turned to come after me. It wouldn't be the first time someone had called us in, but fortunately I never saw him again.

Uneventful ride home and way way more than I should have risked given the S.A.H. orders. But it felt good to scrub the rust off and find some rhythm. It was also a little shocking about how it played out tonight, actually pacing cars that were definitely oversteering a bit in the slow corners. I'd read so many encounters where the results were the opposite, due to the greater contact patch of four tires on the sports cars. So the kids tonight must have really sucked! They made my night though!

Coming downhill at about 60 MPH the readout was showing about 16.2:1 at steady coasting throttle, dropping from there if I gave it any throttle. Altitude didn't seem to make much difference. There was a headwind when I made the highway on the way back. Interestingly, at the same speeds on the return of ~75 MPH the AFR was about 0.4 leaner than with a tailwind on my way out, so the airbox pressures do translate to more air than fuel under higher airbox pressure conditions. In fact, they appeared to move directly proportional to wind gusts. So to carry that thought forward, my conclusion would be that AFR readings performed during dyno runs in static shop air are inaccurate to real world conditions.

I've plotted the numbers into a spreadsheet, much like on a dyno chart, with riding impressions and mileage results...if that ever becomes a possibility.

[kz550]

This has everything to do with a motor refresh I did over the winter. The new engine doesn't like the old engine's carburetor settings. So right after, I dropped the main jets one step. But was still getting a too-rich condition only at WOT.




So yesterday I dropped the main jets another step, but left the SuperTrapp diffusers the way they were. I want to see the results first, before maybe adding the one diffuser I removed back.

That took care of the WOT/WFO flat spots, but was still able to occasionally get a 10 to show at WOT, so I might put the one SuperTrapp diffuser back. Noticeable pickup in midrange too by going with the leaner main jets. The lowest AFR witnessed was a 10.8:1 and it didn't feel like it prevented acceleration, even at higher altitudes. Only saw it for a split second, before the readings went more into the mid-11s. Mind you, this is on a RAM air bike, not one that relies only on atmospheric pressure.

AFR at Idle is still about the same as before, but under acceleration I'm mostly seeing ~12.5:1. At steady throttle from 1.5K - 3.2K it gets continuously leaner as we all would suspect, then steadily drops from 3.2K to 5K RPMs anywhere from high 14s into the lower 13s. Above that it doesn't change much unless I'm accelerating hard, then no matter what the RPMs are, I'm seeing 11s & 12s. Acceleration is quite good even when it shows 11s, surprisingly. At higher altitudes doing some 6th gear roll on/off/on does kind of throw out some crazy numbers. Some of that probably has to do with exhaust gas lag in getting to the O2 sensor to be measured.

In downhill riding scenarios at steady throttle it's common to see high 15s, low 16s. Off-throttle, low engine loading really doesn't mean anything other than that the engine isn't adding much fuel to basically spin the motor and to push what little drag there is being produced above 50 MPH. My bike seems to prefer anything from 11.0:1 - 14.7:1 on level ground, at speed.

Throttle response and acceleration throughout the RPM range feels really good and meaty now. I can certainly live with how she's performing:

Glad I have this device. I would not have thought the mains to be the current issue without it, but they were exactly the issue.

Now to see how the bike performs at lower altitudes and what kind of MPG numbers the newer motor is truly capable of, without the handicap of jets that were about ~5% too rich for riding conditions.

[kz550]

After several rides to lower and higher altitudes, the best compromise (carbs are a compromise), are their current settings with the diffuser back in place. I need it in there for the higher summits and it doesn't make fueling so lean it's an issue at lower altitudes. If I need to ride at one or the other for extended periods, I can add or remove onel diffuser, but fueling is really good. I'm not at the maximum nor the minimum diffusers, so for me, there is a sweet spot.

But it gets better, because I purchased a second AEM UEGO gauge and wired up my other 2000 Ninja ZX-9R with a Muzzy pipe. With virtually the same jetting, the SuperTrapp bike is head and shoulders above the Muzzy bike in power and performance. I'm still looking to see if the Muzzy exhaust bike can do better at WOT operation with richer or leaner jetting than what's in it now. My sense is that one step leaner is the right way to go, but the UEGO readings off both bikes, say I should try to match the AFR numbers from the SuperTrapp as best as I can to the Muzzy. I know it can do better. I just got its mid-range a ton better, which is resulting in a parallel, but richer fuel graph from 1K - 8K RPM than the SuperTrapp bike's fueling. I definitely need to clean up the mains. At 3/4 - WOT, the Muzzy bike is definitely richer and too rich, making it obvious that 3/4 throttle works better for it than WFO throttle at the moment. But ironically when compared to the SuperTrapp's graph, it's leaner near redline and fluctuating more in the higher RPMs.

The Muzzy bike is a work in progress, so this isn't conclusive for me yet. I'd like to try out different main jets to maximize the WOT performance, per Factory Pro's recommendation, which is to set the mains first and work your way down. Then I can fine-tune the mid-range and clean up the pilot circuit with the help of the EUGO readings.

Comparing the two bikes:
Off the line, SuperTrapp wins. Mid-range, SuperTrapp wins. Top-end, SuperTrapp wins. Rapid throttle response, SuperTrapp wins. Fuel efficiency, SuperTrapp wins. Exhaust weight, Muzzy wins.

Haven't actually quarter miled my two bikes against one another, but I did run the SuperTrapp against another owner's 2000 ZX-9R. His is a lower mileage bike that I helped him rejet this Spring, running the stock exhaust, with a -1 countershaft sprocket for quicker acceleration. He confirmed the changes we made woke his bike up. Then we did about 10 first gear roll-on drag races through 3rd gear mostly him egging me on to show me how quick his bike was. The two bikes were evenly matched in 1st geary, but my SuperTrapp bike was basically walking away from his bike or holding it's own if his bike got the jump on mine. The longer the drag, the further my bike pulled his, even with his acceleration friendly gearing. While I was, I also wasn't surprised at how well my SuperTrapp bike did. This bike scares me enough to know it has a dangerous side that needs to be respected.

Back to the Muzzy bike though, I checked the compression too thinking that must be contributing to it's lack of oomph, but its valve clearances are within specs and compression numbers looked good. So racing the two bikes wouldn't be fair to the Muzzy bike at the moment. It's just not ready and would get its clock cleaned.

I'll know more in a week or two as I experiment more with the Muzzy's jetting. Since its exhaust flow is not adjustable like the SuperTrapp's, jetting is the only thing that I can use to adjust mixture readings. One way or the other, with the AEM UEGO gauge to help guide me, the Muzzy bike should improve to some level where I don't think I can improve it anymore. Then I can make a final determination on how it compares to the SuperTrapp bike. But I'm already eyeing my third 4" aluminum racing series muffler in place of the Muzzy CF muffler. I'm just not confident the Muzzy exhaust does as much for performance as the adjustable SuperTrapp. And performance is a motivator to make changes.

p.s. once the Muzzy bike is tuned ideally, I have my baby, my 2002 ZX-9R (SuperTrapp) that is ready to accept the UEGO gauge too. It's much closer in performance to my 2000 ZX-9R, but I'll be curious to see if it too can benefit some after I draw out it's RPM fuel mapping and compare it to the other SuperTrapp bike. Stay tuned. There's more to learn.

[kz550]

The Muzzy bike is still a work in progress. I checked the valve clearances and replaced the Factory Pro +4 ignition advance with a stock timing rotor. From a previous ride, I started to see a glimmer of hope, but the jetting was too lean though the midrange and too rich on top. So I adjusted the fueling some more, reducing the mains one step and bumping the jet needles up a notch to what Factory Pro recommends as a starting point.

There's no way to sugarcoat it, the Muzzy pipe sounds sterile and stupid, like slapping your hands together in water when opening it up from 1/2 to WOT. Power is awful other than at WOT from 7K RPM up. The bike is just falling on its face by comparison, if I try to ride it like my other SuperTrapp ZX-9Rs. There is power and acceleration there, but it feels like its 15 HP down on the SuperTrapp bikes. For instance, rolling from a stop. With the SuperTrapp bikes, you almost don't need to go above idle while slipping the clutch. It's effortless. With the Muzzy bike, you have to rev it a little and slip the clutch for what seems like an eternity, by comparison. With the SuperTrapp bikes power is like a Tesla's powerful electric motor, it's instantaneous, everywhere and always on tap. With the Muzzy exhaust, if you want the same kind of power, you have to downshift a couple gears and by then, if it was an emergency, it's too late.

But I'm still working on it and I'm getting closer now that the main jets are fairly close and timing isn't interfering. I know what I have to do next inside the carburetors, since I cannot tune using an adjustable exhaust, like with the SuperTrapp's easy to swap diffusers.

FWIW, the AFR is still too rich, but primarily in the low-end and midrange. I think I can take some of that out, split the difference at the jet needle, it will hopefully restore some of the power that's not there like it could be.

I'm serious, I feel like a sitting duck without the SuperTrapp kind of power I'm accustomed to. But I'm going to suffer through it until I think it's as close to ideal as possible, before ordering my aluminum racing series SuperTrapp slip-on. I just want to see for myself what other people experience. And so far, I can see why there are so many owners who are talked into putting on some other aftermarket muffler and soon after sell their bikes. I'm about to that point, except for the fact I know there's a soul in there waiting to be unleashed.

[kz550]

Quite the classic story behind today's 213 miles to reserve. A personal record for this Muzzy equipped bike, its first time over 180.

On Friday I needed fuel in the bike's tank since it was empty and ended up stealing the SuperTrapp 9R's tank out of convenience. It was full and only had 10 miles on it. Rode around Saturday doing a whole lot of WOT and high RPM tests to accumulate AFR data off the UEGO. Figured I'd go for a stroll again with it, not remembering that if I did need fuel I'd need to bring the key to unlock the tank cap. At this stage however, I was completely unaware, only focused on testing out the new jetting.

I took off for some local hills, a 60 mile loop and I think the odometer showed I'd put about 145 on the day before. Actually was just cruising with it thus far today (Saturday), since I've not ridden this bike in anger, not even once. It hasn't been up to the task, which explains that. At the turnaround on the other side of the mountains, I saw another HD or something coming over the hill towards me, still about 1/4 mile away, so I turned around and kept up my cruising pace through the lower slow MPH zone only to find the HD wasn't a HD, it was a sportbike and he was hauling. So I dropped a knee into the first corner then the second and asked the Muzzy bike for the beans. Not great, but I was accelerating. The other rider was a little further back when I exited the parabolic corner, and I moved over on a short straight to let the guy have the right of way if he so chose. I was content in cruising with my unknown quantity Muzzy. Next thing I knew, he brushed past me, deliberately within a couple feet doing 50 over what I was.


Hey, I know that guy. He's on his Kawasaki H2 and he's really moving, probably more so to impress or intimidate the guy on the 20 y.o. sports-tourer. He had carried too much momentum into the turn ahead and had to slam on his brakes, so...oh yeah, let's see if I can keep up with a 200+ HP H2. lol Sure enough, I picked up momentum and reeled him in, making up about 60 yards of the 100+ yards he had on me when he zipped past, as we entered the lower set of corners. In each successive turn, I took another 10 yards out of his H2, then he'd gun it on the straight and pull away, leaving a black rubber line on the road from his rear tire. But not pulling away as much as I would have imagined for a H2 belching out black smoke as he hammered the throttle. He definitely couldn't corner well with the bike. By this time, I was down into 4th gear to get the bike to pull and carry my lines I'd need to catch up to him. Still figured I'd get dusted. I mean, he's an ex-dirt flat track racer with the advantage of a near new state of the art fuel injected supercharged bike at altitude (6,000' AMSL). He knows how to ride fast. He should blow the doors off my sluggish, test-n-tune Muzzy 9R.

The H2 had again taken back the full 100 yards back on me into the next turns after the straight, which had some 180s and elbows. With the help of my upgraded Triumph Nissins (on my Kawasaki I made back about 70 yards on the second of two turns, made up an additional 10 or so in the 180 and the next turn, before he'd launch again onto a longer straight ahead. But this time, in a better gear, I was able to minimize the losses there, somewhat because he choked setting up for the S-turn ahead, slamming his brakes whereas I could carry my momentum through the S and into the next 180 uphill corner. Now I was within 15 yards of him and I came out of those turns within about 10. He launched his H2 for all it was worth, taking back some, then losing it back in a fast LH sweeper that lead into another LH 180 and RH elbow. Going into the 180, with the help of my Nissins, I was again about 10 yards from him and by the time we left the RH'er, I had closed to within feet of his rear wheel. Damn it, though! If I had been on the SuperTrapp ZX-9R, I could have truly messed with his head and gone for a pass much earlier and probably repeatedly. That bike just leaps out of corners, power is like turning a faucet handle. I wouldn't have been successful, of course, but that would have been hilariously funny to do, just so he'd know he'd been owned by a ZX-9R.

And it gets better and worse! Going up the next straight we were both coming in just sub triple digits (KPH ), nearing an area where the local sheriff likes to hang out. It was hot out and I was going to toss caution to the wind, simply because what are the chances the sheriff had just showed up and was parked and roasting, just to catch speeders? No way, he's probably back at the station dunking donuts in an air conditioned room.

I again was carrying my momentum after the straight to reel him in and was about to drop the puck on the floor in a blind RH corner when the vehicle going in the other direction was the sheriff! The H2 rider and I were easily 30 over as we both scrubbed speed off as the sheriff passed by. We were busted, no ands ifs or buts. I thought about pulling off and accepting my fate, but that's never worked out in the past. I'd seen the sheriff's tail lights as he went around the bend behind us. You know that feeling where you just hope he didn't have his radar on or something.

The H2 and I proceeded to ride onward around additional corners, both acting like we were angels, not a couple of hooligans tearing up deserted backroads. I didn't look back over my shoulder, didn't want to. But in my mirrors I couldn't see either the sheriff or him lighting us up. So about 3/4 of a mile ahead, which felt like eternity to get to, I split off into a residential area, while the H2 rider stuck to the main highway. His route only gave him two options. One, onto a road that would double back in the direction we'd come or at the fork up ahead he could continue into a town where there was almost certain to be a deputy. I figured if the sheriff was still turning around or had radioed up ahead to his deputies, he'd only be able to tag one of us this way...and probably not me.

By this time my odometer was at about 175 miles, but I was up high and could coast through the rural residential area to a fire escape road I knew about, if only I could make it there without being detected. The fire road let out down below onto another highway that if I took the short route home, would possibly take me past the sheriff again, if he were lucky enough to spot me out there, so I considered my fuel and felt it would be close, but I was going to take the long way home and go the other way. I was headed directly opposite to my way home and was planning on looping around several other mountain ranges that would probably add another 60 miles to my trip. Mind you, I had no idea what to expect from the Muzzy bike's range. IIRC, it had never topped 180 miles (to reserve) before I'd made changes to the jetting.

But I made it. So no performance award. No stranding. Still feel a little lucky in the circumstances. But the bike came through when I needed it to live up to its potential.

[kz550]

Lately, I’ve been focusing more attention on my SuperTrapp (ST) sE1, because the Muzzy is getting closer to something resembling acceptable throttle response and power. I’m experimenting with new fuel jetting to match to the flow characteristics on my ST and Muzzy exhausts. The reason for that is that I’ve already established what I like. I know the ST worked beautifully on my first two Ninja ZX-9Rs. The number of diffusers isn’t at the maximum nor at the minimum. The ST FAQ helped me arrive at what worked best, great torque and top end, while civilized for around town riding. Not an all-out track-only setup, like my Muzzy will probably take. Thus far the Muzzy exhaust has been a major expectations letdown.

Focusing on my ZX-9R sE1, I tried some shortcuts by adjusting only the jet needle height, similar to what worked on the Muzzy bike, but the results this time were steps back. Factory Pro, which makes jet kits, says in their how-tos to always start with the main jet; set the best main jet first. They are right There is no shortcut to any of the lower fuel circuits until the best main jet is established. Back on track, I found the best main jet at the end of the week. Then methodically, I reset each of the lower fuel circuits based on what my Lambda UEGO gauge was telling me. Two more adjustments and a test ride was all it took.

From the ride on Saturday, August 9th, I still bumped into some 10.9s (AFR) while in too tall of a gear for the slow mountain corners I was in, but high and low, she felt much more like her old (motor) self. Range was phenomenal. One complaint about power, there was a hint of throttle lag, but not always. And that was due to a fueling change, something I'll have to keep an eye on. But otherwise, she just Eff'in boogies and the ST sounds badass!

Lots of high 11s getting on the power on summit curves or passing slower traffic. Cruise AFR (75-80 MPH) is in the 12.9 - 12.5 range. Still richer than I would like for steady throttle, but for now, I think I'm okay with all of it. Top to bottom, bottom to top and everything in between just feels awesome or close to it. How awesome? It makes my Muzzy ZX-9R feel like a 600 from idle up to about 8,000 RPMs. Only then does it begin to rival the ST’s power output. That’s the meat of where I ride on the street. I’m not going to ride in corners at 8K RPM just to be in the Muzzy’s powerband! There’s way too much engine power by then for me to control.

Sunday August 10, 2020, was a hot dry Summer day and also a good test to find weaknesses in my tune. We had planned a group ride which included some summit crossings and elevation changes of greater than 5,000.’ The results however, didn’t find any new weaknesses, so I may still be over-fueling, but the throttle envelope is quite unrestricted, matched beautifully to my SuperTrapp’s flow.

Instead of taking point of the group ride initially, I followed. That afforded me a better vantage point to test throttle response and acceleration under varying conditions without affecting other following riders. Settings confirmed midway through the day, I moved to point for some spirited riding and had the riders stack up behind me going back into the mountains. I stuck to the bike’s top two gears to constrain acceleration, so as not to excessively speed, nor present a danger to anyone out on our mostly deserted 3 - 4 mile twisty mountain road. But I did unleash her in a spirited manner.

We had established at the bottom that we were ready to stop for a late lunch picnic at the top of the mountain, which gave us the forum to tell our ride stories from each rider’s perspective. Once settled in for lunch, the last two riders said they lost touch with us shortly after we hit the curves at the bottom and began the climb. Going faster than they normally did, they were aghast that they could only see the third rider, but not me and one other rider after only a few turns.

The third rider was keeping their own pace and said they were able to see me and one other rider briefly going around a bend midway up the mountain, but also lost touch. The fourth rider, the one behind me was on his Suzuki SV-650 sporting a Leo Vince SBK muffler. He has only been somewhat successful by redlining his 999cc KTM 990 Super Duke trying to keep up on a previous ride on this same mountain. He went on to volunteer in a very animated way that he had his bike pinned in 3rd and 4th gears giving it everything he had to unsuccessfully chase down my 9R. He made some jokes too, in jest, of course, but followed up by repeating several times to me his astonishment of the situation he believed would turn out much differently, that my ZX-9R was no joke. Even with a more nimble bike, he said in a disheartened tone, that my 9 just disrespected his Suzuki everywhere. And by the time we finished the main series of twisties a few miles later, the gap between us had stretched to several hundred yards before we both slowed to allow for the other riders to regroup.

Not my Muzzy ZX-9R and not just any plain old ZX-9R. My Ninja ZX-9R, one of two that I own with awesome SuperTrapp mufflers. And now for the record, apparently it is this 2000 model ZX-9R sporting an aluminum racing series SuperTrapp that is in his words, no joke.

Observed a lot of 11.4s climbing and some 17s descending. Exceptionally hot in the latter portion of the day. No pinging and I tried to make her ping. She wouldn't do it, no matter the gear, load, how hot the engine coolant temp was or throttle position. One constant is that no matter what the steady throttle reading is, opening the throttle makes it lower. For fun, on the way home we each did one run at the old airstrip. I took it up to 135, which at WOT showed a ~12.5:1. The trend was heading leaner from the 11s it was showing going through 110 MPH in top gear. Some of that could be skewed by the hot dry air temps and altitude too.

[kz550]

As circumstance would have it, I had to take my backup bike, my other SuperTrapp ZX-9R, for a group riding trip. We met several other riders, most who were on sportbikes too. By day we rode curvy roads. By night we social distanced at the local brewery. Good times. Eventually, as all festive trips go, it was time to head for home. In one last opportunity to ride together, we rode out of our way to take in the windiest road we could find. And because one of our riders brought their Ducati Panigale V4-S, an 1103cc 219 horsepower fire breathing obnoxiously loud sportbike eater, we were required to stop every 70 miles or so for him to take on fuel. In our last stop for fuel, I flipped the cameras on to share the experience.

My backup ZX-9R hasn't undergone the complete UEGO conversion just yet. I'm still assembling information on my other two bikes. But the tune on my 9R isn't far from perfect, just not the same as the other two at the moment. The O2 sensor is already installed though.


We had six riders in our ride group. The Ducati and KTM riders are trackday regulars, each capable of lapping 20+ seconds/lap faster than I can on my 9Rs, but it's been a while since I've been to the track. Some of that has to do with my fear of accidents at speeds I wouldn't ever see on the street. So my only comparison with them is from technical curvy roads we ride together. The order is ZX-9R, Panigale, Super Duke.



On went the cameras. My primary concern was safety and not holding up my faster track riding buddies. SuperTrapp power didn't disappoint. I edited the full video down to just the unobstructed portion and sped it up so it would appear more exciting. At the mid-start, a slower vehicle had just moved over to let us through, so I stretched the legs a little, then slowed on the next straight to regroup.



* Pronunciation

[kz550]

Got the old girl fixed. It was my mistake putting the original burned out fuel pump into the bike, thinking a simple filing of the contact points would solve it. Apparently on some of them, when they fail they stay on and end up draining the battery while you're riding, just like what happens when the stator on a motorcycle or alternator on a car fails. Lesson learned. She has a new fuel pump and 250 miles under her now.

She's just shy of 143,000 miles. I know she's old and many would discard such a bike at that age or sell it for something newer, but she's without debate my bike of choice. It almost feels like I'm still getting her customized to my liking, each iteration feels better than the last.

For her maiden voyage we took her out riding into the mountains with two other sport riders. One was on a new KTM 790, the other on a Ducati 1098. She was not only the class of the field, able to gap them or chase them down depending on how we lined up, she was running in her normal 2.5x their range mode. So either they were pushing and burned a lot more fuel or they weren't pushing and they still burned more fuel. I've seen the videos of them riding, so I'm guessing they were pushing.