WHAT IS IT? KTM, Husqvarna and GasGas are all spec’ed with WP XACT air forks, which work great for a wide range of riders, but there's a loud portion of riders who can’t wrap their minds around air forks. There are several suspension companies that have built their businesses around creating drop-in spring conversion kits for the WP air forks. Surprisingly, WP joined in on the fun and came up with their own spring conversion kit, capitalizing on the wide range of riders who prefer spring forks over air. For this test, MXA used WP’s spring conversion kit for the KTM 65SX and had it re-valved and tuned by REP Suspension.
WHAT STANDS OUT? Here’s a list of things that stand out with REP Suspension’s KTM 65SX spring conversion kit.
(1) REP. The REP acronym stands for “Research Engineering Performance,” and Mark Johnson is a mad scientist who leaves no stone unturned when it comes to finding the perfect suspension settings. Mark worked at WP for 10 years before branching out on his own, and he also writes a monthly column in MXA (see “Suspension Simplified” on page 90). For the past few years, REP has been based out of the AEO Powersports dealership in Murrieta, California, but now REP has grown and needs more space. REP has its own building now, right down the road from AEO.
(2) Concept. REP Suspension utilizes a re-valved version of the WP XACT Pro 7500 drop-in cartridge kit that the production-style fork caps to keep the bike AMA-legal. This is intentional, and something done on request, while keeping the bike legal for the Limited (stock) class. This modification also allows the rider to pressurize one of the fork legs for more front-end hold-up. REP also modifies the fork springs to meet optimal preload measurements and achieve a preload target different from what WP originally designed the kit for.
(3) Performance. Right away our MXA mini wrecking crew test riders felt that REP’s spring conversion kit had a much plusher and smoother feel than the stock air fork. Their biggest praise for REP’s spring conversion kit came when navigating large braking bumps and larger jumps. They felt a much more controlled feel as the fork worked through their stroke. This allowed our young test riders to blast through rougher parts of Glen Helen’s track with more speed and aggression.
Another positive was that our 65cc test riders raved about how controllable and comfortable the front end of the 65SX felt in the turns. They stated the bike was more balanced through the turns, allowing for smoother and faster cornering. Of course, the best part about spring forks is that you don’t have to set and check the air pressure every day at the track.
WHAT’S THE SQUAWK? Being that the price is so high, this kit is not for everyone. This is an upgrade designed for the 65cc Junior Cycle racers who are racing the Amateur Nationals.