Mc Garage

2017 Kawasaki Z125 Pro DCR Cam Install and Dyno Test Video

Does DCR’s high-lift cam push the Z125’s power to new heights?

July 1, 2016

The last time the Z125 Pro was on our Dynojet dyno we’d just installed Yoshimura’s RS-2 Mini exhaust. Well, Daniel Crower Racing (danielcrowerracing.com) saw our video and volunteered to send up one of their performance cams. Never one to turn down an opportunity to spend some time in the shop, we graciously accepted.

As with most things on the little Z125, installing the cam was easy and only took an hour and basic tools. One snag was getting a wrench on the cam-chain tensioner bolt. The starter motor is in the way, so you have to unbolt and dislodge it. The starter is held on with three Phillips-head bolts—I used an impact driver to get them out and then replaced them with hex-head bolts for easier removal the next time around.

Besides that, I struggled to get the cam timing right during reassembly because the motor kept bumping past top-dead center. If you can get a helper to hold a wrench on the rotor bolt so the motor doesn’t turn, you’ll have a much easier go of it. And of course, you need to reset valve clearances once the new cam is in.

On the dyno the cam gifted the Z125 with 0.62 more peak horsepower, pushing the top of the curve from 9.14 to 9.76 horsepower. But all the cam’s gains are from 7,500 rpm up. Below 7,500 rpm, the bike is actually making less power and torque than stock.

Red is stock, blue is with Yoshimura’s RS-2 exhaust installed, and green is with the pipe and the DCR cam. As you can see the Z “comes on the cam” at 7,500 and keeps building power all the way to the rev limiter. That top-end power comes at the cost of midrange grunt.©Motorcyclist

That sort of shift in power is pretty much what I'd expect from a hi-lift cam. Static cam timing is always a compromise (that's why Ducati Variable Timing technology is so rad), so in order to build up top-end performance you typically have to mine power from the midrange. On the plus side, that stronger top-end performance pushed the Z's top speed up 3mph, from an indicated 63 mph on the stock bike to a smoking 66 mph!

It’s worth noting that our Z still has the stock air filter and air box, as well as an unmolested ECU. We’ll be adding those parts next, and I expect we’ll see more top-end improvements and hopefully some of the midrange power restored as well.

So, Daniel Crower Racing’s $298 cam nets you substantially better high-rpm performance, a few more mph in top gear, and puts a dent in the midrange. Say what you will about whether it’s a worthwhile modification, but it sure is easy to install!