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2021 isn’t a ground breaking year for Kawasaki’s KX450, but it did get a couple key changes that make a difference on the track. Kawasaki put more of its R&D focus on the KX250 in 2021 with several changes. I mean the 2020 KX450 was on the podium in almost every media shootout, so a couple refinements could go a long way. I spun some laps on a tight, ruttier type of track rather than the high speed chop of GH and Cahuilla, where most of the other media outlets tested, just so I could abuse the clutch as well as see how the new handlebar made me feel in tight ruts. Here are some thoughts about the refined version of the 2021 Kawasaki KX450.
2021 Change Points:
New Cone Disk Spring Clutch (On The Track):
Last year I had a problem with the Nissin hydraulic clutch slipping under load. The clutch slipped at times under heavy load/under throttle on super deep tracks. You could also feel the lever start to creep in towards your grip when accelerating out of corners at times. To combat this you had to remove the judder spring and add a fiber to the clutch pack. For 2021 the updated cone disk spring clutch feels much more linear than the 2020 and slips less under load. I say “less” because it can still slip if abused, but now without the judder springs, the KX450 gets traction to the rear wheel in a much better fashion. I experienced more rear wheel traction from area 2-3 in corners and was able to get on the throttle extremely hard without breaking the rear wheel loose (similar to a KTM feel). I also thought the engagement was a little wider and I could feel that when doing starts back to back with the 2020. It did feel like the clutch change Kawasaki made in 2021 did affect throttle response a little however. I thought the 2020 had slightly more excitement on low throttle situations, but also broke the rear end loose more when the track hardened up. I will gladly take slightly less throttle response with this new cone disk clutch in order to roll my corners better and exit harder. This change can also roll over into your 2019 or 2020 KX450 as well! You can simply order the basket, inner hub, pressure plate, fibers, steels, springs, clutch cover and update your older KX to the cone disk style.
2021 Change Points:
Renthal 839 Fatbar (On The Track):
It’s just a bar Keefer!? Well… It isn’t just a bar, but it’s also a change to your rider traingle. Yes, of course you can put another set of bars on your older KX’s, but I am still going to tell you about this 2021 change. The 839 Fatbar is the same bar Honda uses on their CRF250/450R models and I love it! It has a lower height (91mm) than the older 971 7/8 bend and a rise that is only 51mm. I also felt slightly more connection to the front tire when pushing hard through corners. How? The larger diameter doesn’t flex as much on the ends of the bar, giving me more of a positive feel through the clamps down to the front wheel. The Renthal Fatbar wasn’t so rigid on slap downs that I felt I needed to go back to 7/8 on this chassis! Welcome to 2021 Kawasaki! Happy to have you!
Weight Feeing (Chassis): The 21 KX450 is very free feeling yet connected, which makes this bike have a very light/nimble feeling through corners. I am able to lay it down with ease and cut down under a blown out rut almost as easy as a KTM/Husqvarna. I do get a little twitch on de-cel (which can be fixed with a fork spring change), but it wasn’t a horrible or un-easy feeling. Straight line stability is still the same straight and arrow Kawasaki feel that you expect, but with added traction because of the clutch. The frame absorption is the best attribute to this machine and other manufacturers should take notice of how well this KX450 feels when the track goes to crap. The whole bike feels friendlier than a lot of other machines on square edge and the only other one that comes close in comfort is the Yamaha YZ450F
Engine Feel: Just in case you were trying to decide on if the 2021 KX450 is better than the 2020 version, scroll back up and read about the new clutch and what it does to the power of the new KX450. The 2021 comes on slightly smoother yet still has that lighter/free-revving feel and has minimal engine braking. I went with the stock ECU settings and the white coupler and seemed to like that the most when the track was deep or hard pack. The white coupler gave it slightly more throttle response, but didn’t make it jumpy feeling like the 2020 KX450. The 2021 KX450’s mid range has a nice amount of meat and the smoother pulling power of the top end/over-rev is noticeable on longer straights. I didn’t lose mid to top end pulling power with the black coupler (compared to the the white one), but I could ride the KX450 more aggressively through corners. I however feel like the black coupler is simply too smooth on deeper tilled tracks. The 2021 engine is super connected to the rear wheel and never steps out coming out of corners. This is an impressive power plant! I revisited my 2020 map and preferred the standard map with the white coupler for the 2021 version.
The 2021 Kawasaki Showa fork has tons of comfort, but is also too soft/divy for my liking on de-cel. The track I tested at required you to be hard on the throttle then brake heavily coming into the corner and the fork was too low in the stroke, which caused some oversteer. Going stiffer on the compression only hurt de-cel bump comfort, so I settled on going slower on the rebound, which helped some. I then went to a heavier spring rate (0.51) and the balance of the bike greatly improved off throttle. I would think some of that comfort would diminish, but I ended getting more comfort on de-cel bumps because the fork stayed higher up in the stroke. The shock is soft on high speed compression so going in on your high speed compression helps make the shock feel less empty on its end stroke. Below is a setting that I think can make a wide range of riders happier with their stock Showa suspension.
2021 KX450 Base Suspension Settings:
Spring Rate 0.51 Spring (0.50 is stock) *If B level rider and over 200 pounds 0.52 springs are also a great option*
Oil Level: Standard
Compression:11-13 clicks out
Rebound: 11 clicks out
Fork Height: 3mm
Spring Rate: Standard (190 pounds or over, try one spring rate heavier)
Low Speed Compression: 16 clicks out
High Speed Compression: 1 1/8 turns out
Rebound: 10-11 out
I want to cleanse my sins right here! To the team green die hards out there, you’re right! I NEED to ride this machine more on my own time. Every year I say this and I end up only riding this bike to get you all settings and then I hand it off to one of my testers to create more content. I am NOT going to be doing that in 2021. Can you Keefer Inc. readers/listeners please hold me accountable for this statement in 2021? Every time I ride this bike I really enjoy it, so I must follow my heart and ride this more in 2021. Sincerely, Kris.