2017 Kawasaki Z125 Pro Bazzaz Z-AFM Install, Dyno Test, and Top Speed Run Video

When we left off we’d slapped a performance intake on the Kawasaki Z125 Pro’s throttle body in place of the restrictive, labyrinthine stock airbox, and supplemented the air increase with more fuel from a Bazzaz Z-Fi piggyback fuel module (click here to see that installment video). That pumped up power quite a bit (both mods complimented the DCR camshaft and Yoshimura exhaust we’d installed earlier), but the little Kawasaki was running on a universal base map and we wanted more precise fueling.

Installing a Bazzaz Z-AFM self-mapping module (see www.bazzaz.net) seemed like a worthwhile and easy add-on, and with lots more engine mods in the pipeline we figured a self-mapping function would be pretty handy. True, we have a dyno in house and can build a map pretty easily, but it's a lot more fun to do it while you ride!

The Z-AFM costs about $350 and comes with a piggyback module that plugs into the Z-Fi fuel controller. Bosch’s latest 02 sensor is included in the kit and sniffs the Z’s exhaust to decipher the air-fuel ratio. From there, the Z-AFM module makes fuel-trim suggestions that you can accept with the push of a button (on your laptop). It’s an impressively easy system to use, and besides having to get a larger O2-sensor (a $30 accessory) welded onto the Yosh header, it’s easy to install.

A note on that bung: I opted to have it tacked on in place of the stock 02-sensor bung. That’s good positioning since you want the sensor as close to the exhaust port as possible, but the bigger sensor sits right against the cylinder and oil line. If I were to do it again, I would angle the bung out another 10 degrees to give the setup more clearance. To be fair, Greg at MNNTHBX, who suggested the Z-AFM, warned me that clearance might be an issue.

Once installed, you just plug the Z-Fi into your laptop, use its easy interface to tell the Z-AFM to start recording, and then go for a ride. After a 20-minute blast around town I’d gathered data (including info that showed the Z was running dangerously lean at 100-percent throttle) that I then applied to the fuel map with the click of a button.

On the dyno, the refined fuel map pushed power from 10.27 to 10.46 hp, while torque seemed to suffer a little in the lower half of the rev range. A quarter-horsepower isn’t much, but it’s progress, and the goal with the Z-AFM wasn’t necessarily to achieve big power gains but to allow us to rapidly tune the bike’s fueling. The Z-AFM is so easy to use that it’ll make future mods (like a big-bore kit or a different exhaust) very quick and easy to map for.

Another interesting note: A top-speed run revealed that it's time to install taller gearing. We're banging against the rev limiter in 4th at an indicated 67 mph. The previous top speed was 66 (with about 9.8 hp, stock it would go about 63 mph), but it took forevvvver to get there. This time it sprinted up to its max speed quite a bit faster.

More speed definitely makes the Z better for everyday riding, and with the Z-AFM installed we’ll be able to quickly and easily adapt the bike’s fueling as we continue to mod it. I think 70 mph is within reach!