50 Hours On The 2019 KTM 450SX-F

I have been hammering down a lot of motos on the 2019 KTM 450SX-F before it has to make its way back to the KTM offices to make way for the 2019.5 KTM 450 Factory Edition. There are still some consumers out there that are concerned about KTM’s durability and wonder if you can trust the Austrian machine over the course of several hard hours. Well to try and give some real world feedback, I have purposely been a little “over abusive” on this particular test steed to see if in fact we can trust the KTM engineers and their R&D department. I have just went over the 52 hour mark last week and have accumulated over 20 of those hours in the past three weeks on rough test tracks near my home. This KTM 450 SX-F has seen its fair share of the testing workload on many parts, accessories, and product evaluations in its 50 hour lifespan. A 50 hour engine, on my scale, is like a 75-80 hour engine on a regular blue collar average racer/rider. If you’re looking for shiny new photos of the 2019 KTM 450 SX-F you came to the wrong place. You might as well go hit the back button and look at the 2019 450 MX Shootout photos because these pictures are of a work horse and not a show pony. Below are some of the key points I wanted to share with you current 2019 KTM 450 SX-F owners and maybe potential KTM buyers about our test unit. 


Engine/ECU Settings: KTM’s R&D department is well aware that they may have missed the mark on stock ECU settings on the 2019 KTM 450 SX-F, but that doesn't mean you should just dismiss this engine. Some “other” media outlets are claiming that it’s too difficult to ride with the rich down low and lean up top feel of the standard ECU setting. There are a couple things to consider here: one that this engine does take some time to break in and feel like it should and two it does get slightly better with some time. Let me explain… When you first get your KTM 450 SX-F and ride her it may feel very tight, sluggish off the bottom end, have some de-cel pop, and may even flame out on you in corners. Some of these symptoms die off after 8-10 hours of riding time on the engine. I used the stock ECU box/settings for the first 16 hours and I had some of those symptoms until around hour 9, then the de-cel popping went away and also some of that sluggish feeling coming out of corners. The rich feeling still seems apparent under low RPM’s no matter what, but KTM is aware of this and will be making some changes to the ECU come factory Edition time. So does that mean you current 2019 KTM 450 SX-F owners are screwed? No. I just wanted to make it clear that this bike is very much rideable in stock form without a ECU re-flash. 

If you DO NOT want to spend the money on a Vortex ignition you can get your standard box re-flashed from Jamie at Twisted Development or Chad at XPR Motorsports. Both of these companies have a better ECU setting for you current orange brigade riders out there. Either one of these guys have a map that gets some more excitement and a cleaner air fuel setting to make the power even more useable. If you DO want to spend the extra $800.00 or so, the Vortex is simply magic for this engine. The engine delivery still remains so smooth yet easier to ride and increases the use of second and third gear. Going to the Vortex ignition gives you the option to ride with less effort while deceasing your lap times because the workload is simply less with the power character the Vortex gives the orange machine. I repeat you DO NOT have to have the Vortex to make the KTM 450 SX-F engine better! You can save some money and re-flash your current ECU!

What about durability once you go with a Vortex ignition? I have yet to have any durability issues with going to an aftermarket ECU that is correctly mapped from either said company above. It is one of the only modifications you can make to your machine that will make a noticeable difference in power without sacrificing the lifespan of your engine. 


What about clutch life? I am notoriously hard on clutches and I usually only get 9-10 engine hours on any given Japanese manufacturer clutch, but with the KTM I can almost double my lifespan. The KTM 450SX-F has only seen two clutches in the past 50 hours and I have been letting my engine run on the same oil for 5-6 engine hours at a time. To me that is impressive. I also DO NOT notice slippage under load when the engine gets hot. The hydraulic clutch is something that I have come to appreciate more through the years and although the engagement of the KTM is a little on/off feeling the overall performance of the clutch itself is amazing under heavy race oriented type stress. 

What about engine maintenance? I am not going to sit here and tell you I am some great mechanic and I am busing out valve clearance checks every 20 hours. I did check the valve clearance after 25 hours and they were within spec and I haven't checked them since. Like I mentioned above I have used Blud Racing 10/40 or Maxima Premium 10/40 oil in this bike and have only changed the oil every 5-6 hours. I am usually a 2-3 engine hour oil change kind of guy, but the KTM has held the rigorous amount of riding time that I have put on it. 


Chassis/Suspension: During the course of the 50 hours I spent on this machine I went back and forth with the stock WP suspension and the WP Cone Valve fork/TRAX shock. The Cone Valve fork provided me with more front end traction (under lean angle) and I could just be more aggressive with getting over my front end without it being inconsistent on a longer moto. The TRAX shock has more of a dead feeling than the stock shock yet provided only minimum comfort gains (over stock). The stock WP shock is very good for my weight and for the combinations of trans we ride here in California. If you’re serious about racing and performance than I would recommend this set up. IF you’re a weekend warrior and want to improve your riding, DO NOT worry about this as the stock stuff will be just fine.

I ended up running the stock AER fork for the last 20 or so hours on the KTM just to see if I can push around the track and found out that running the standard air pressure at 10.5 bars, with the compression at 20 clicks out, and the rebound at 14 clicks out was sufficient. This setting provided me the comfort without getting too harsh through the mid stroke during longer motos with bigger braking bumps/square edge. If you find this setting to be a little harsh on your hands and you're around 185 pounds go with a 10.6 bar setting, compression at 24 clicks out and a rebound of 14 clicks out. This will help hold the front end up on de-cel and help with harshness. 


What about the 2019 KTM’s stiffer frame? The stiffer chassis takes some time to get used to if you're coming off of a 2018 model. Don’t be scared off by the 10% increase in torsional rigidity stiffness. Just like the engine, the 2019 KTM 450 SX-F frame took me a little longer to break in to feel some quality bump compliancy (compared to Japanese machines). I see/hear riders complaining about the 2019 frame stiffness, but to me as a long term owner/consumer I prefer this. Why? A couple reasons: one the 2019 has a more positive cornering character than the 2018 does, feels lighter through mid corner, and doesn't feel clapped out at 50 hours! The 2018 frame (at 50 hours) felt worse than a 100 hour Yamaha YZ450F frame. With the stiffer chassis that KTM came out with in 2019, my test bike feels better now than it did when I was at 25 hours. The overall compliancy has softened up a little bit, but not so much where I feel the frame flexing under load like I did with the 2018 chassis.       


Gearing: I have ran the stock gearing, tried going to a 14/52, but have settled on a 13/49 for my final spec that I prefer at most tracks. I liked the 14/52’s traction character out of corners, but I feel like I lost a a little third gear recovery. I like running third gear through corners and with the 13/49 I feel like I can leave the KTM in third gear (with stock ECU) and fan the clutch minimally to get the orange brigade back into the meat of the power. The 13/49 gearing also doesn't hurt second gear pulling power that much to where I am forced to shift earlier than I did with the 13/48. I am fairly certain that Husqvarna will be making that 13/49 gearing change to their 2019.5 Rockstar Edition models as well. Give it a try if you're a third gear kind of rider. Oh and did I mention I have only changed out one set of sprockets/chain? Yep. 

Handlebars/Grips: I have been on a crossbar kick lately, so the Pro Taper Fuzion “SX RACE” bend has been on the KTM 450 SX-F for over half its life. I was in search of a slightly taller bar bend than what comes stock on the KTM (height 79.5mm, 52mm sweep) and a bar that flexed more, so going with the Pro Taper SX Race bend was great for me, especially in corners. I can still get over the front of the bike, but my elbows are up a little more naturally and I feel better when standing on the bike. If you're a crossbar kind of guy, the Pro Taper Fuzion bar has a EVO-ish flex character and will not feel as rigid as some other crossbar brands. Also note that the stock lock-on-grips/throttle tube also can get heavy after around 20 hours, so check your plastic tube for wear. The plastic on the lock on grips can get rough inside and make your throttle pull hard. IF you ware looking to put standard grips on go with a Motion-Pro throttle tube. I prefer plastic tubes more than aluminum ones for flex reasons. I am not a full time racer guy anymore so I don’t need the durability of an aluminum tube .   

Air Filter: Buy yourself a KTM 250SX two-stroke air filter cage because they come without a backfire screen and then go get a Twin Air filter. Just doing this little modification gave me some added RPM response which helps the KTM feel even lighter in tight sections of any given track. 

Wheels/Tires/Axle Blocks: You will have to check your sprocket bolts and spokes religiously, but if you use a little blue Loctite on your sprocket bolts you should be good. You can also increase the rear wheel traction by going with some Works Connection Elite axle blocks that will eliminate the fixed left side axle block from your axle. This allows both axle blocks to float under heavy load (acceleration) and will not give you a binding rear end (harsh) feel. It sounds minimal, but makes a difference on acceleration chop. You can also run your wheel a little farther back if you're changing your gearing to get some added straight line stability that the KTM can use at times. 

Rear Brake Pedal Spring: The stock one sucks! I break my brake pedal spring every 3-4 hours! You either are going to have to load up on brake pedal springs or go with a CRF450R brake pedal spring with the rubber over it (condom style). This helps with the vibration that the spring experiences, so it doesn't break. 


FMF 4.1 Muffler System: I have tried a lot of systems for this bike, but there is only one that I liked better than the stock system. The FMF 4.1 helps bottom end roll on power out of corners, gives you some added mid range meat, and keeps the stock system’s top end intact. You will shed almost 1.5 pounds and the exhaust note is not obnoxiously loud. I leave the insert out of this system and run it how it comes in the box. The KTM R&D team in Austria worked together with FMF to develop this muffler so it ensures that the air/fuel ECU mapping is correct when purchasing this system. Smart. 


Seat: I went with a Selle Della Valle seat for added butt traction out of corners. This seat is really good, but also really hard on your butt! I have been chaffed more times than I can remember, but it keeps you locked in that’s for sure! It also is super durable and takes washings well.