The 2021 KTM 450 SX-F orange brigade is an amazing machine to ride! It only gets better with some modifications and some tweaks. The KTM 450 SX-F responds well to a few mods and with that makes for one hell of a fun motorcycle to ride/race. Here are few things that you can do to make your 2021 KTM 450 SX-F better. Do one or do them all, but just note that each mod makes enough difference on the track for my tired old ass to type about it when I get back to the office.
Engine/ECU: For 2021 KTM has a better ECU setting and although it’s clean, I still would like some more added RPM response/puling power. I have been on the Vortex ignition bandwagon for a couple years with this machine and for 2021 it hasn't wavered. If you want the same great rear wheel connection as well as more pulling power everywhere, look into a Vortex ignition from Chad at XPR Motorsports or Jamie at Twisted Development. I have turned a lot of KTM riders onto this mod and have had a 100% approval ratio. What I like about this modification is that it doesn't hurt reliability and makes for a very usable yet powerful engine for almost every type of rider. Yes, it will set you back around $800.00, but to me is much better than slapping on a muffler system and will do more for your engine. A stock re-map will not get you nearly the rpm response or pulling power that a Vortex will give you. Another good reason to get a Vortex ECU is that they have great resale value. You will also most likely be able to keep that Vortex ECU in circulation (if you get a new 2022 KTM) until 2022.5 as that will most likely be the year that KTM will release it’s new model.
Suspension: If you haven't listened to my WP XACT Pro Components suspension podcast you may want to at least check that out, but if you're sticking with the stock suspension for a while, you can try this setting to see if this helps comfort when the track gets rough. This setting below should be in the ballpark for riders around 165-200 pounds, but if you’re heavier than 200 pounds going to a stiffer rear spring will help the ride attitude of the KTM. I have went to several tracks and tried many different settings, but this specific setting had the most “track toughness”. The KTM’s stock WP suspension doesn't quite have the comfort like the Husqvarna does, but the KTM/WP set also holds up more in the stroke, which is a better fit for me personally. To get some added comfort back with the added hold up, try this setting.
Fork (Stock Triple Clamp):
Height: 5mm
Air Pressure: 11.0 Bars
Compression: 13-14 clicks out
Rebound: 15 clicks out
*With KTM Hard Parts Triple Clamps or Ride Engineering Split Clamps*
Height: 5mm
Air Pressure: 11.1 Bars
Compression: 15-16 clicks out
Rebound: 13 clicks out
Shock:
Sag: 104mm
Low Speed Compression: 10 clicks out
High Speed Compression: 1-1/2
Rebound: 11 clicks out
WP XACT Or Spring Conversion:
This is a question I get a lot! Which is better? Should I get a spring conversion or XACT Pro Component fork? I have tried Enzo’s KYB conversion as well as a REP valved XACT fork and both have their advantages. The Enzo KYB conversion soaks up small bump/hard pack chatter better than a REP XACT fork, but the REP XACT fork moves less and to me has slightly better performance with slightly less comfort. Both spring set ups are better than other re-valved AER set ups that I have tried and to me the spring set ups are way more consistent throughout the day. You will have to decide on how much money you want to spend (Enzo KYB Spring Conversion is around $2000.00 and the XACT fork is around $3000.00) as well as what type of rider you are in order to get the most out of your suspension. If you like a fork that moves in the stroke a lot and follows the ground well (front tire contact patch), the KYB conversion is great. If you want the most hold up as well as a fork that allows the rider to charge/hammer through big bumps easier, the XACT fork set up is also a great choice.
Chassis: Aftermarket engine mounts are all the rage right now and some of you may not have the money to spend on a pair of engine mounts for your KTM. I will say that I do feel like the KTM chassis is stiff when new, but be patient as it will break in and feel better after 15 hours or so. I decided to play around with torque specs on the engine mounts for fun and stumbled across some more comfort. If you’re experiencing a stiff feeling chassis sensation and want the KTM to settle while leaning (under throttle), there is an inexpensive way to achieve some extra front end traction (as well as an overall more planted feel). You can torque all top engine mount bolts to 30Nm. This band aid will give you a more planted sensation when on throttle while leaning the KTM 450SX-F through sweepers and fast straights. You will have to make sure that all engine mount bolts have blue Loctite to ensure they do not back out (you should do this regardless if you keep all the bolts in or not). You can also try torquing your swingarm pivot bolt to 95 Nm (instead of 100Nm) to help rear end traction out of corners. The downside to doing these mods is that the chassis will flex a little more, so if you’re riding deep tilled tracks this modification might have too much flex for some (especially when chopping throttle).
Handlebars: The stock Neken handlebar is too stiff and doesn't offer too much comfort. Throw them in the trash. Get yourself a set of Pro Taper bars and make your arms and hands happy again. The Pro Taper SX Race bar worked well for riders from 5’8 to 6’1. The SX Race bend comes in a crossbar or crossbar-less style and is 800mm width, 87mm height, 54.5 rise, and 54mm sweep. If you’re looking for a better “stand up feel” from your KTM look for handlebar close to this measurement. If you do like the stock bar try the Pro Taper Husqvarna Stock bend with 5mm bar mount risers (Ride Engineering sells these).
Triple Clamps: After riding back to back with the stock triple clamps, the KTM factory clamps and the Ride Engineering clamps I have realized that the stock clamps are stiffer. I have since installed the Ride Engineering triple clamps on our 2021 KTM 450 SX-F with excellent results. The front end has more of a softer initial touch on slap downs and the fork action is smoother on de-cel bumps. It’s crazy to think that the fork feels softer now with the Ride clamps installed, but that is exactly how it feels when riding on the track. I was able to increase my air setting on my fork to help hold up off-throttle and kept more comfort through the entire stroke (with the stock AER fork). I also get slightly more lean angle front end traction (or cornering stability) with the Ride clamp because the front end isn't bouncing around inside long/choppy ruts. The KTM factory clamps are close in comfort to the Ride clamps, but offer slightly less straight line front tire feel.
Rear Brake Pedal Spring: Purchase a Honda CRF450R rear brake pedal spring with the rubber around the spring. The KTM rear brake pedal spring vibrates and will break every 3-4 engine hours. Orrrrrrrrr. Get a Fasst Co rear brake return spring and be done with it! Fasst Co’s rear brake return spring offers tunable pedal resistance and a more controllable feel by placing the spring in compression instead of tension, minimizing the "on-off" feel of most rear brakes.
Gearing: I like the stock 13/49 gearing for most conditions. If you remember last year I thought 14/52 was better in sandier conditions, but have come to the realization that I liked the gear spacing more with the 13/49 gearing.
Twisted Development Exhaust Flanges:
The Twisted Development exhaust flanges are shaped differently than the stock OEM flange, which can change the engine character of the KTM 450 SX-F. I went through several during testing and found out a size/shape that can actually enhance the low to mid range power character. Compared to the stock piece the TD Performance flange will give you better throttle response through area 2-3 (mid to exit) of corners. Another advantage to me is that the TD flange helps pulling power out of corners as well and helps third gear lugability. The TD flange just helps the RPM’s pick up quicker, which in turn makes the KTM feel lighter when the track gets bumpy. There is no need to remap your ECU and it takes minutes to install.
The TD flange works with the stock headpipe/muffler system or any aftermarket system. I tried it on a stock muffler system as well as a full FMF system and with both, the TD flange helped in aforementioned areas. For $200.00 bucks, to me, it’s a great way to get a little more snap out of your KTM 450 SX-F.
Rear Axle/Axle Blocks: Going to a Works Connection Elite axle block kit or Ride Engineering axle block kit will get rid of the fixed left axle block on the stock KTM’s axle. This will help the rear end to move more freely under throttle and improve the shock’s comfort on acceleration chop. Both are great, but you will have to decide if you want a complete axle/axle block kit like Ride Engineering’s or just the blocks themselves like WC’s.
Muffler: To me, FMF makes the best muffler system for the KTM 450 SX-F. There are some other companies that have other bikes dialed in more, but on the KTM, FMF has got it down. You will get more low to mid RPM response as well as more mid range pulling power. Top end is increased plus the over-rev is as good as stock. It is one of the few times that I was impressed because it was actually better than stock in almost all areas. The downside is that you must keep up on muffler packing (every 10-12 engine hours) because the FMF will blow out and that could damage your expensive titanium can. Did I mention that you will lose almost two pounds with this system? If you slap on spring forks you will be gaining almost three pounds. You can get most of that back with a 4.1 Titanium FMF Muffler system.
If you have any questions about any of these settings or mods please contact me at kris@keeferinctesting.com and I am happy to help you.