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Being that the Kawasaki KX450 is all new in 2024 I told myself that I would spend a good amount of time on this machine to dissect its strengths and weaknesses. Well now with 30 hours on the green machine, let’s discuss some important pieces that may help you with your new Kawasaki.
Durability: I mean we are not exactly at the 100 hour mark so let’s not celebrate yet but I am putting this in here because I think it’s worth noting that (knock on wood) the chain slider, chain guide and other fasteners haven’t completely shit the bed like on previous KX450s I have had. I have installed a D.I.D. ERT3 gold chain on for durability but the stock chain isn’t a complete piece of crap. I ran the stock chain for almost 15 hours which is more than I can get out of some other stock chains. The subframe is still intact and I haven’t destroyed any Pro Circuit mufflers over the course of these 30 hours, Hallelujah. The new 24’ KX450 airbox is tight and the filter system is easy to work on but is kind of janky. Twin air is making filters that are a little better for sealing and they are making a new cage system that won’t allow the filter to suck inward when opening up the throttle. So far, I haven’t had too many headaches with the new KX450 and this is one of the reasons I am liking this machine.
Just Note: There is a factory dealer modification bulletin to the frame that is getting sent out but I have not had this problem on my two test units. Kawasaki has noticed that there could be a crack in some frames on the inner right side of the frame spar (picture shown). If you do notice a crack in this area, please take your 24’ KX450 to your local Kawasaki dealership so they can remedy the problem. Do I know exactly what they will do? They will either fix the problem or replace your frame. This IS NOT happening on all frames so this IS NOT a wide spread RECALL at this time.
Pro Circuit Ti-6 Pro: Keefer, what about the Pro Circuit Ti-6? You can check a review of the Ti-6 right here on my site, but I have since switched over to the “Pro” version to see if I feel any difference? The Ti-6 Pro version is an AMA legal muffler for professional racing and has a little different core inside the muffler can. The muffler is meant to pass AMA/FIM sound regulations and with that of course you will get a little less low end/RPM response but with the TD Vortex that I have, this “Pro” version gives me a completely different feel to the rear wheel. With a little more linear low end power delivery, this Ti-6 Pro makes it easy to roll on the throttle sooner out of corners and keeps the rear wheel slightly more connected to the ground. I did try this “Pro” version with the stock ECU and although still MUCH better than the stock system, it didn’t have the low end power that the regular Ti-6 provided. I will say that the Pro Circuit muffler system is A LOT BETTER THAN THE STOCK MUFFLER! The Ti-6 slip on is also better than the stock system but you will not get the mid-top end pull that you get out of the FULL Ti-6 (or PRO) system(s). Mitch and the guys have made a nice gain in power with this muffler and I haven’t been able to say this in a long time but, this KX450 PC muffler system gives your machine more power everywhere over stock! That is something that is hard to do lately in the aftermarket muffler world but Kawasaki is giving these aftermarket companies an easy sell here. This is one of the first things that I would do to my KX450 when I got it from the dealership. A Pro Circuit Ti-6 or Pro muffler system. I prefer the “Pro” sound as it has a much more pleasant note to it than the Ti-6. I also cut the screen out of the insert and then put the insert back in for back pressure. The KX450 likes some back pressure for low end/RPM response.
Hinson Clutch Kit: The stock KX clutch isn’t bad and I like the clutch action at the lever but I was looking for a little longer life as well as maybe some added connection to the rear wheel when I as riding in hard pack areas. Coming from Hinson clutch kits on other machines I have noticed more clutch life as well as just a general better rear tire connection feeling when under load out of corners. This is the same feeling I get with the Hinson clutch kit (basket, inner hub, pressure plate, plates) on the 24’ KX450. Engagement at the lever is slightly wider with the Hinson set up over stock and so far my clutch plate life has been better than with the stock clutch guts inside.
REP Suspension: Mark over at REP Suspension has been working hard to get me a base setting that is comfortable and work well with this chassis. Since this chassis has so much comfort to it with a blend of good cornering character I was looking for the Showa suspension to offer me a little more hold up when coming into braking bumps at speed. Compared to the stock suspension the REP valving still keeps that faster stock fork feel that follows the ground well when leaning on throttle on the edge of tire, but I can now charge harder into bumps without getting a little twitchy feel through the bars like I do with the stock valving. I will say that I am still looking for more mid stroke comfort but we are already on the second spec so this will be an evolving portion of these articles. The shock is great on high speed compression compared to the stock valving as it has more hold up in the rear on acceleration and on slap down landings. The rear of the bike doesn’t kick side to side on de-cel and has a good amount of rear end traction on acceleration bumps out of corners. I hav kept the stock 105mm sag and am now running 3mm on the fork height to keep that nice stability that I enjoy so much on this chassis.
Twisted Development Vortex ECU: You don’t need a Vortex ECU to get some more power out of your 24’ KX450 as removing the air box grommet, drilling some holes in the side panel and installing a Pro Circuit muffler can help this bike a lot already. However, what fun is just stopping there? Why not let Jamie at Twisted Development map my 24’ KX450 to the PC muffler, airbag mods and ETS Racing MX18 racing fuel. I gave Jamie my bike to map on the dyno to the mods that I have done here (and will probably stick with for a while) and the difference is amazing. Even though I am not a dyno geek, Twisted did get almost 4 more horsepower out of the Vortex ECU compared to the stock box. The stock ECU setting is super rich so there is room for improvement with the Vortex already but mapping it to your muffler and fuel makes this bike even more powerful yet not so snappy that it feels like a YZ450F. The KX450 power (with these mods) now has more pulling power but more rear wheel connection feel than compared to my 2024 YZ450F test bike with the same mods (muffler, fuel, Vortex). The KX450 is easier to roll on the throttle in corners without wheeling and has this almost KTM-ish like linear power that is long and usable. I will still say that the KX450 is still a second gear in corners type of bike and is not a third gear cornering bike like the YZ450F, but second gear is so long on this KX450 now that I don’t mind it at all. Second gear is so usable and even though third gear is much better than when it was in stock trim, I like getting in and out of my corners in second gear. The power is so linear that it doesn’t bind the suspension like some other bikes do when rolling corners in second gear. This ECU really changed the power for me and made the 24’ KX450 much more fun to ride.
3D Printed Air Filter Cage: I was looking for an open air cage without a backfire screen as Twin Air didn’t have theirs out yet so Justin Kopcak on Instagram makes his own with his 3D printer. He is based out of Texas and is a great dude. I’ve only met him a couple times but using his 3D cage helps throttle response and low end feel. Look him up on social media. It’s crazy what you can find on Instagram these days.
ETS MX18 Racing Fuel: This isn’t a MUST but it’s nice to have a fuel that gives your bike more power and low end out of corners. The ETS MX18 fuel is a high end racing fuel that can withstand hot temps and will not boil as easy as VP MR Pro 6. You can have Jamie at Twisted map you a Vortex ECU with this fuel or pump gas but you will be getting the most benefit with race fuel.
Gearing : I am currently back on stock 13/50 gearing with these mods. I was on a 13/51 but it hurt my cornering too much as it didn’t allow second gear to pull as far as I liked yet didn’t make third gear that much more usable. The juice wasn’t worth the squeeze.