My friend Jon picked up a new XTZ the other day and yesterday we put the bike on the dyno to see what we could figure out to unleash some more power from the bike.

We fitted a PCIII from his previous XT660R, loaded a zero map to allow the bike to run on the default ECU fuel settings and I gave the bike a few runs until I started getting consistent HP figures.

Note, before people ask why the dyno numbers are low, please note that I run my Dynojet dyno at around 4500 ft above sea level and it is set up to measure torque in Ft-lbs, not NM. It seems to be a common problem with Dynojet dynos at this altitude to not compensate correctly, so if you want to know how much the HP and torque figures will be at close to sea level altitude, add 10 to 12% to my dyno figures. The correct way to do it is to take my HP figures and divide it by 0.9 to 0.88.

The 1st question we had was how this bike's HP and torque output compares to that of a stock XTR's. The dyno run below shows the difference between a stock XT660R and the new XT660Z. Both bikes where brand new with less than 300km's on the clock. The XTZ is the blue line and the XTR red.



As you can see, there is almost no difference in power output between the two. Only around 0.8HP difference at peak, so it is very safe to say that they deliver the same HP in stock form. Actually, in this case the XTZ was slightly better. As said earlier, take my dyno's 37.33HP / 0.88 and you get around 42HP from both bikes.

Next we made a custom PCIII map for the stock XTZ to see how much the fuel mapping would change power output. PLEASE NOTE THE FOLLOWING. The XTZ is running a bit lean (around 14:1 A/F Ratio) in the low to mid RPM ranges when you use less that 60% throttle. Then after 60% it tends to run rich, meaning lower than 13:1 A/F ratio. I strongly suggest that you do not install an aftermarket filter or exhaust without a PCIII or other fuel device.

Below is a dyno run showing the HP gains from the PCIII and a custom map that I built for the bike. Nothing on the bike was changed. Stock filter and exhaust, snorkel in place.



The PCIII with custom map made a big difference. The bike gained around 2.5HP at peak RPM, meaning it would push out around 45HP if I tested this at sea level. Jon who rode the bike with the new mapping said that the popping backfires under deceleration is much less now and it feels quicker when you accelerate. We checked the acceleration times in 4th gear and the new map helped the bike to accelerate from 2200 to 7200 RPM more than a second faster.

Then we played around with removing the snorkel alone, and we gained yet again, especially midrange power. There is a massive gain by doing this. I am not going to post that run as the stock filter did not fit snugly without the snorkel. I will test the bike again with the DNA filter and stage 2 adaptor this coming week and post the results.

We found another mod that really is going to give the bike a jump in HP, but you will have to wait and see.

More feedback coming soon.

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Disclaimer: any mod undertaken, are carried out at owners risk