FMF FACTORY 4.1RCT MEGABOMB SYSTEM
APPLICATION: All four-strokes (Tested here on 2011 KTM 250SX-F)
-All new incorporating the latest in Resonance Chamber Technology.
-Patented core shape lowers sound level while maintaining maximum power output.
-Patented canister shape increases internal volume for more sound absorbing material.
-Patented chamber design to enhance and refine exhaust pressure.
-Factory Forward Engineering centralizes mass and is less prone to crash damage.
-Tuned exhaust with optimized core specifications for each application.
-Innovative rear endcap for simple installation of tuning top inserts or spark arrestors.
WHAT WE LIKE
-The system is much lighter than the stock KTM boat anchor. It knocked several pounds off our KTM 250SX-F test bike, and in all the right places. Our more sensitive test riders could feel the difference in the way it allows the bike to handle, out on the track.
-Power gains are immediately noticeable and plenty impressive. Throttle response is snappy and immediate, and the bike enjoys a much beefier hit down low. In addition to the improved low-end, the Factory 4.1 system also packs a noticeably bigger punch in the middle that really makes the new Katoom come to life! Hitting tight inside lines was easier accomplished with the system on, as it yields much better power for said instances.
-Top-end over-rev is improved slightly over stock, and the bike continues to pull into the upper echelons of the rpm range.
-The system is easily rebuilt, and FMF offers muffler-packing kits that fit perfectly into the 4.1RCT muffler.
WHAT WE DIDN’T LIKE
-As is always the case with KTM motorcycles, changing the exhaust system is an exercise in logical deduction. While the stock system requires you to unbolt the rear shock to remove it, the FMF system is easiest to install when starting from the back, as in muffler first, followed by the mid pipe, then header pipe last.
WHAT WE REALLY THINK
It’s been a while since we were this impressed with the performance gains yielded by an exhaust system on a 250cc four-stroke. The 2011 KTM 250SX-F is one of the fastest bikes in the class in stock condition, but bolting on an FMF Factory 4.1RCT Megabomb system makes it feel like a full-blown race bike.