Dyno Day

After hearing so many good news stories about how an MT-10 responds to a decent tune, I bit the bullet and booked in for a re-flash yesterday. I had been putting that off until I added a link pipe, and then the tuner recommended an AIS blanking kit as well. I had last minute doubts about the link pipe, and ultimately decided to refit the standard cat and EXUP system as I found the Leovince decat and Akra muffler just too obnoxious around town. I am getting old I guess. Refitting the cat was easy, the cables were difficult until I worked out the routing and where they pass through the undertray; the shop manual was a guide but not quite enough. When I first turned the bike on I could hear the servo complaining but that stopped when I adjusted the cable slack.



The Dyno is located in Paeroa about 1 1/2 hours ride away, and for good measure we had high winds, cold temps and heavy showers, so the ride down wasn't the most enjoyable. The dyno is operated by Brett Roberts, he's been an independent mechanic and tuner for decades and has been dyno-ing for more than 15 years; he know his onions and is a go-to guy for many local racers.



Once strapped in a new cable was connected to the ECU plug (there's some blanked off pins for the purpose) and this cable and the diagnostic port were connected to the tuner's laptop via a Woolich racing box. O2 sensors were removed and a temporary external sensor connected to the tuning box. I've seen plenty of dyno videos but being there in person is a whole new experience; inside the dyno cell the deep bellowing noise from a redlining MT was incredible, and watching the bike fight against the hold down straps and compress the fork was cool. Being nerdy, I was also interested to see the goings on within the oil sight glass...



The baseline run got 138 bhp and a fairly wonky air-fuel ratio; lean down low, rich around 6-7 then lean again up high. After some 7 different iterations of fuel map and ignition timing, the best run yielded 150 bhp and smoother A/F ratio. I learned that even a warm engine doesn't give its best first time up, and a couple of dyno pulls are needed to get the oil hot for least drag, and in all 21 dyno pulls were recorded. It took a few minutes to load up each altered map to the bike.



I asked the tuner about storage of the original map and whether this could be re-loaded if I wasn't happy; the answer was yes, but no-one has ever asked for it. My test ride explained that, from the first touch of the throttle the bike responded more smoothly and immediately, and had a much more eager feel. The ride home was impressive, smoother and more mid-rangy and happy to be left in a higher gear, or revved out hard. I won't use 150 bhp but the mid range work is wonderful.