Issue link: http://trailridermagazine.uberflip.com/i/935202
easy fix. Although the bike has EFI, it also had a nice Dubach aftermarket pipe. The only problem with that was the prior owner did not reprogram the ECU, so the bike has the typical off idle hit of a 4 stroke MX bike with EFI and then a bad flat spot in the middle of the powerband. The flat spot in the mid-pow- erband was clearly driven by lean conditions due to a more open exhaust. We tried all three ECU settings and determined that the setup for a hard-packed track was the closest to correct. We could go two routes: Buy a reprogramming kit for the ECU or try a spark arrestor to see if it would provide the requisite re- striction to fix the lean condition. We went with the second option since it was only 20 bucks and would be a good add even if it didn't accomplish the goal of smoothing out the powerband. As a bonus it took some of the unnecessary bark out of the exhaust note yet left it with a quieter but still throaty rumble. We like bikes to sound good but it's important to protect those precious riding areas. Simply adding the spark arrestor paid serious dividends as it smoothed out the low-end transition without sacrificing torque. The mid spot flat spot was completely gone and the transition to the top end improved significantly. Yes, you can restrict exhaust and pick up power at the same time! It's mostly about power delivery in the end anyway. For the final step we focused on the most important phase, the suspension. For that we turned to Race Tech. Race Tech continues to be my favorite stop for DIY suspension work. The 2013 KX came equipped with the Showa SFF system. The SFF stands for single function forks. All of the spring work is done by the right fork with the valving in the left. It sounds like an odd combo but it works and keeps weight down. It's also set up for an MX track and the stock setup is horrible in the woods. Race Tech has the goods. Servicing the spring side was super easy. We replaced all the seals, bushings and re-sprung it for Jack's weight. The left fork — now that was a different story. I was on the verge of sending it to Race Tech. They are pros and their rates are reasonable. I've worked with Louis Martinez at Race Tech a few times and he was able to talk me off the ledge. Louis instructed me to make a homemade spring compressor with a bench vice and ratchet strap rather than try to sell me a $200 tool. He explained that once I cracked open the inside I'd have a good bit of carryover from revalving the KYB's I'd been doing. Although the valv- ing side of the Showa SFF was indeed more complex than an open bath KYB, all of the principals were similar and it wasn't too bad. I was really glad he talked me into doing it myself. Mission accomplished. The end result was perfect! After breaking in the forks, Jack brought the bike up to Loretta Lynn's for a good ride. "The end result was awesome" he said. Jack was now able to control the bike at walking speed and then roll on the power to jump a log without any deflect. Those pesky roots and rocks that would cause havoc at higher speeds on the old MX suspension were now a non-event. Jack continues to add goodies to his bike, such as a better case guard from Topar, a Cycra skid plate, along with bark busters and other woods goodies. Now that the bike is properly set up for the woods, Jack's riding abilities continue to improve since he's no longer fighting his bike. His smile while riding says it all though! February 2018 23