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The Triumph TF250-X is the newest 250 motocross machine so that means we haven’t had a lot of time with aftermarket mufflers yet until now. In stock form the TF250-X has a smooth low end power with a wide mid to top end but maybe lacks a little bit of excitement on low end (with standard 2024 mapping). FMF created a 4.1 titanium muffler for the new Triumph in hopes that it creates more power and a happier TF250-X rider. We bolted one on and tested it for ourselves.
Installing the Megabomb headpipe and 4.1 muffler is not as easy as others we have put on as it does take a little finagling of the Megabomb to get it to line up with the holes on the engine mount, but with a little wiggling we got it to line up well enough to attach the Megabomb headpipe. The 4.1 RCT muffler slip fits to the Megabomb headpipe easily without issue and the holes/bolts line up to the rear of the subframe perfectly. There wasn’t any binding while installing, just a little finagling with lining up the headpipe bolt attachment. The use of your stock headpipe springs will be utilized and help snug the front of the Megabomb to the Triumph’s cylinder head.
The FMF 4.1 titanium muffler system helped with low end/pulling power yet didn’t exactly give me more low end RPM response. The stock system has slighly better crack off idle and gives the the rider a fun feel/perception but still could use some more pulling power out of the corner when comparing it a Yamaha/KTM. With the 4.1 system installed the initial crack was mellowed somewhat but the pulling power out of corners in second and third gear was noticeably better. (Just for reference I run a 13/49 gearing instead of a 13/48 as well as the 2025 ECU spec that your Triumph dealer can update you with. I have been running this spec with the stock muffler system but with the FMF system the pulling power is even better). The TF250-X now has more mid range recovery and a harder pull once coming out of area 3 of corners. Mid range is also lengthened over stock and the mid rpm response is better with the 4.1 system installed. Top end is slightly improved over stock but it isn’t as noticeable as the mid range punch the FMF 4.1 gives. The over-rev feels similar to the stock system so don’t expect more over-rev in any gear you’re using.
With the titanium 4.1 system you will not be losing a ton of weight (just over one pound) over the stock system but the FMF system is quieter and deeper sounding than the stock racey sound. Repacking every 10-12 hours is required if you want a long life span from your 4.1 muffler can. I was impressed by this system and for $899.99 for he muffler and $475.00 for the headpipe this isn’t a cheap aftermarket option. I do think this is a reasonable upgrade over the stock system and it compliments the gearing change as well the ECU update.
You can check out fmfracing.com for more info or if you plan on ordering one, you can do so over on RMATVMC.com by using our banner on this site.
Note: We left insert in (screen cut out) with this model as it created a better throttle feel down low and gave each tester more rear wheel traction than without insert.
Any questions about this test, please feel free to email me at kris@keeferinctesting.com
