2024 Kawasaki KX450 and KX450X

loganhallrv2
Posts
39
Joined
8/31/2015
Location
East Bernstadt, KY, USA
9/7/2025 8:15pm
Yeah it’s definitely an odd place for it to crack. Especially since I haven’t seen anyone else having any issues so I’m gonna chalk it up...

Yeah it’s definitely an odd place for it to crack. Especially since I haven’t seen anyone else having any issues so I’m gonna chalk it up to just being a fluke deal.

NicNak wrote:
Were the subframe bolts loose? Those bolts do not like to stay tight so gotta check em. If they get loose enough it could cause a...

Were the subframe bolts loose? Those bolts do not like to stay tight so gotta check em. If they get loose enough it could cause a cracked subframe. 

Yeah I’ve always tried to keep a check on the subframe bolts. But have had one of the lower ones kept coming loose a little blue loctite an no issues since.

1
9/7/2025 8:25pm
It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here...

It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here in over month stupid dusty and got involved in a pileup on a hillside and overheated the bike trying to get up it. Excuse the nasty soapy stuff on the exhaust I was in the middle of cleaning and going through the bike when I found the crack. IMG 6903 0

Mine cracked in the same exact spot at like 40 hours 

9/8/2025 4:58am
It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here...

It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here in over month stupid dusty and got involved in a pileup on a hillside and overheated the bike trying to get up it. Excuse the nasty soapy stuff on the exhaust I was in the middle of cleaning and going through the bike when I found the crack. IMG 6903 0

Stock or aftermarket exhaust?  If aftermarket, what brand?

1
loganhallrv2
Posts
39
Joined
8/31/2015
Location
East Bernstadt, KY, USA
9/8/2025 9:42am
It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here...

It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here in over month stupid dusty and got involved in a pileup on a hillside and overheated the bike trying to get up it. Excuse the nasty soapy stuff on the exhaust I was in the middle of cleaning and going through the bike when I found the crack. IMG 6903 0

Stock or aftermarket exhaust?  If aftermarket, what brand?

Stock exhaust, really wanting to splurge for an fmf but hard to beat the durability of the stock exhaust.

The Shop

30minmotos
Posts
1028
Joined
8/7/2025
Location
Rising Sun, MD, USA
9/8/2025 10:01am
It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here...

It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here in over month stupid dusty and got involved in a pileup on a hillside and overheated the bike trying to get up it. Excuse the nasty soapy stuff on the exhaust I was in the middle of cleaning and going through the bike when I found the crack. IMG 6903 0

Stock or aftermarket exhaust?  If aftermarket, what brand?

Stock exhaust, really wanting to splurge for an fmf but hard to beat the durability of the stock exhaust.

Cut more holes in the airbox and get a vortex before the exhaust.

1
1
MX529
Posts
76
Joined
3/26/2024
Location
Wilmington, NC, USA
9/8/2025 10:58am
It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here...

It had cracked towards the back, close to the exhaust mount. The head gasket was my bad, doing an off-road race and it hadn’t rained here in over month stupid dusty and got involved in a pileup on a hillside and overheated the bike trying to get up it. Excuse the nasty soapy stuff on the exhaust I was in the middle of cleaning and going through the bike when I found the crack. IMG 6903 0

Stock or aftermarket exhaust?  If aftermarket, what brand?

The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end 

People have punched them out and gained better performance 

Ideally the stock can is ugly and bulky and best replaced with FMF or Pro Circuit T-6 


air box mods are free.. vortex will run $700-900 

 it’s up to your skillset to determine what’s best, I’d buy suspension upgrades before a vortex ignition 

49weasel
Posts
975
Joined
4/12/2013
Location
CANAL WINCHESTER, OH, USA
9/8/2025 11:44am
MX529 wrote:
The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end People have punched them out and gained better performance Ideally the stock can...

The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end 

People have punched them out and gained better performance 

Ideally the stock can is ugly and bulky and best replaced with FMF or Pro Circuit T-6 


air box mods are free.. vortex will run $700-900 

 it’s up to your skillset to determine what’s best, I’d buy suspension upgrades before a vortex ignition 

Personally I don’t think the Vortex Ecu is worth it.  Spent the last few weekends trying each map and ultimately ended back on the the stock ecu.   

2
loganhallrv2
Posts
39
Joined
8/31/2015
Location
East Bernstadt, KY, USA
9/8/2025 12:29pm

Yeah, I’ve done done got the airbox drilled out, and and the Chavez map in the ecu. The exhaust would be more for looks then power. Overall pretty happy with the power curve with the mods I’ve done, just like to have a nice exhaust on there. 

datkin128
Posts
279
Joined
12/23/2015
Location
Lakewood, CO, USA
9/8/2025 2:11pm
Yeah, I’ve done done got the airbox drilled out, and and the Chavez map in the ecu. The exhaust would be more for looks then power...

Yeah, I’ve done done got the airbox drilled out, and and the Chavez map in the ecu. The exhaust would be more for looks then power. Overall pretty happy with the power curve with the mods I’ve done, just like to have a nice exhaust on there. 

The aftermarket exhaust makes a big difference on this bike!

2
9/8/2025 3:07pm
Yeah, I’ve done done got the airbox drilled out, and and the Chavez map in the ecu. The exhaust would be more for looks then power...

Yeah, I’ve done done got the airbox drilled out, and and the Chavez map in the ecu. The exhaust would be more for looks then power. Overall pretty happy with the power curve with the mods I’ve done, just like to have a nice exhaust on there. 

datkin128 wrote:

The aftermarket exhaust makes a big difference on this bike!

I agree, the Yosh was a big improvement on mine.

MX529
Posts
76
Joined
3/26/2024
Location
Wilmington, NC, USA
9/8/2025 4:36pm
MX529 wrote:
The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end People have punched them out and gained better performance Ideally the stock can...

The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end 

People have punched them out and gained better performance 

Ideally the stock can is ugly and bulky and best replaced with FMF or Pro Circuit T-6 


air box mods are free.. vortex will run $700-900 

 it’s up to your skillset to determine what’s best, I’d buy suspension upgrades before a vortex ignition 

49weasel wrote:
Personally I don’t think the Vortex Ecu is worth it.  Spent the last few weekends trying each map and ultimately ended back on the the stock...

Personally I don’t think the Vortex Ecu is worth it.  Spent the last few weekends trying each map and ultimately ended back on the the stock ecu.   

Just a free flowing muffler or full exhaust system certainly wakes these bikes up.. they are choked up bad from the factory 


IMG 4392 2

4
NicNak
Posts
1063
Joined
2/18/2019
Location
Palm Desert, CA, USA
9/8/2025 7:57pm
MX529 wrote:
The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end People have punched them out and gained better performance Ideally the stock can...

The stock exhaust has two baffles.. one just behind mid pipe, other at exhaust end 

People have punched them out and gained better performance 

Ideally the stock can is ugly and bulky and best replaced with FMF or Pro Circuit T-6 


air box mods are free.. vortex will run $700-900 

 it’s up to your skillset to determine what’s best, I’d buy suspension upgrades before a vortex ignition 

49weasel wrote:
Personally I don’t think the Vortex Ecu is worth it.  Spent the last few weekends trying each map and ultimately ended back on the the stock...

Personally I don’t think the Vortex Ecu is worth it.  Spent the last few weekends trying each map and ultimately ended back on the the stock ecu.   

Who mapped your vortex ? Cause mine is significantly better than stock. 

9/9/2025 4:20am

I have a PC exhaust (although I’m convinced that a slip on would do the same thing).  I think I’m running the Chavez map.  I trimmed about 1/2 inch of material from the opening of the airbox behind the side panel with a Dremel and tore the foam off the inside of the side panel.  I’m pulling holeshots all the time, and don’t feel like I’m underpowered at any point in my races.  Even better, I didn’t mess up the smooth power delivery that lets me charge late in the motos when my competitors are sucking wind. I’m very happy with my bike.IMG 4359 4.jpeg?VersionId=CuPRj1VyGEW 5sPNb0C RjXQIT

3
1
9/9/2025 7:18am

Raced this past weekend at Glen, and noticed after the moto coolant was leaking out the weep hole and a little oil out the breather hose. Do you guys recommend oem water pump bearings or an after market?

1
NicNak
Posts
1063
Joined
2/18/2019
Location
Palm Desert, CA, USA
9/9/2025 9:01am
Raced this past weekend at Glen, and noticed after the moto coolant was leaking out the weep hole and a little oil out the breather hose...

Raced this past weekend at Glen, and noticed after the moto coolant was leaking out the weep hole and a little oil out the breather hose. Do you guys recommend oem water pump bearings or an after market?

oh yeah i've had that happen. Make sure to get a new water pump gasket too. I don't think it matters but most people would say OEM is best. 

It's kind of a nuisance to change it with the way the radiator & the pipes are all routed. it helps to loosed up the radiator & the the radiator pipe on the far side...just saying for me!

1
RCMXracing
Posts
891
Joined
8/10/2011
Location
N., TX, USA
9/9/2025 9:52am

100+ hrs going strong no issues… aftermarket clutch put in before stock had 30hrs, but it was fine

Funny to me, the throttle cable… still original and that sucker is stretched but gonna run it till out of adjustment 

2
9/9/2025 10:12am
Raced this past weekend at Glen, and noticed after the moto coolant was leaking out the weep hole and a little oil out the breather hose...

Raced this past weekend at Glen, and noticed after the moto coolant was leaking out the weep hole and a little oil out the breather hose. Do you guys recommend oem water pump bearings or an after market?

NicNak wrote:
oh yeah i've had that happen. Make sure to get a new water pump gasket too. I don't think it matters but most people would say...

oh yeah i've had that happen. Make sure to get a new water pump gasket too. I don't think it matters but most people would say OEM is best. 

It's kind of a nuisance to change it with the way the radiator & the pipes are all routed. it helps to loosed up the radiator & the the radiator pipe on the far side...just saying for me!

Thank you, just shy of 10 hours too kind of surprised me

9/12/2025 9:02am Edited Date/Time 9/12/2025 9:05am

For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start new? Finally got myself a syringe and look forward to messing with the oil lvl.

30minmotos
Posts
1028
Joined
8/7/2025
Location
Rising Sun, MD, USA
9/12/2025 9:06am
Leemur891 wrote:
For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start...

For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start new? Finally got myself a syringe and look forward to messing with the oil lvl.

I added 7cc to each leg through the bleeder 

2
Rocket164
Posts
148
Joined
4/18/2017
Location
Napoleonville, LA, USA
9/12/2025 10:39am
Leemur891 wrote:
For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start...

For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start new? Finally got myself a syringe and look forward to messing with the oil lvl.

When replacing the fork spring, I drained all the stock fluid in the outer chamber and added new fluid. 

When only adding fluid, 20cc’s in my case, I removed the top fork cap and added the oil directly to the outer chamber. Quick easy process and may be a better option if adding larger amounts of oil. 

Seems like small amounts of oil (5-10cc’s) can be added through the bleed hole with a syringe. 

I’m no suspension expert, this is my opinion based on a lot of research. 

1
9/12/2025 11:36am
Leemur891 wrote:
For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start...

For you guys that added fork oil, did you just add to what was put in from the factory or did you completely drain and start new? Finally got myself a syringe and look forward to messing with the oil lvl.

Rocket164 wrote:
When replacing the fork spring, I drained all the stock fluid in the outer chamber and added new fluid. When only adding fluid, 20cc’s in my case...

When replacing the fork spring, I drained all the stock fluid in the outer chamber and added new fluid. 

When only adding fluid, 20cc’s in my case, I removed the top fork cap and added the oil directly to the outer chamber. Quick easy process and may be a better option if adding larger amounts of oil. 

Seems like small amounts of oil (5-10cc’s) can be added through the bleed hole with a syringe. 

I’m no suspension expert, this is my opinion based on a lot of research. 

Popping the caps is what I was thinking. Was mainly concerned about mixing oils and/or if that small of an amount would matter. I’ve got some 5wt Maxima in the shop

9/12/2025 11:54am

I’ve always added it 10ccs at a time with a syringe through the air bleed screw holes and I’ve never had any problems doing that.

49weasel
Posts
975
Joined
4/12/2013
Location
CANAL WINCHESTER, OH, USA
9/12/2025 12:25pm
NicNak wrote:

Who mapped your vortex ? Cause mine is significantly better than stock. 

Xpr

49weasel
Posts
975
Joined
4/12/2013
Location
CANAL WINCHESTER, OH, USA
9/24/2025 12:21pm

Is it possible or has anyone put a Brembo clutch master cylinder on ?

9/27/2025 1:58pm

I have a problem with the motorcycle stopping whenever it wants. The fuel pump fault appears on the gauge (4 high and 6 low). The fault appears after 25 minutes of engine operation. I disconnect the ECU and it starts normally. I'm scared of a jump... Has anyone else had something similar happen to them? The engine has 30 hours on it.

ARM670
Posts
2224
Joined
12/11/2020
Location
Napoleon, OH, USA
9/27/2025 2:52pm
5362
1
7
chasetwo79
Posts
1595
Joined
12/1/2019
Location
Truckee, CA, CA, USA
9/27/2025 3:51pm

Talked to someone at the track today who had 250 hours on their 450 already. Lots of woods riding, but he was sending today at the track on that motor and the bike sounded solid still.

4
fiddy
Posts
38
Joined
3/24/2014
Location
USA
9/28/2025 4:13pm

Anybody have a problem with bike getting hot after a riding a moto.Come back and try to start bike and seems like battery is weak and will not start.After it sits for a couple of minutes it starts right up.Bike is running good when I ride it.

nch209
Posts
486
Joined
1/1/2017
Location
NoVa, VA, USA
9/28/2025 11:31pm

Some updates on mine. 

Got my junk vortex ecu back from TD (scumbag here on vital sold me a broken unit), but we got it to work in best overall power mode so it helps the bike, but doesn’t have any adjustability. Kinda jaded over the whole vortex thing, but that’s a whole long story.  Don’t buy these used.  This was under a year old and they wouldn’t stand behind it because I wasn’t first owner.  I get it, but still bummed dude screwed me as he knew it was broken but didn’t disclose it.  Was boiling fuel (pro6) but swapped to the ht flavor and that seems to have cured it  


Went through forks for just a freshening up.  Not too much internal wear, but upper inner tubes had some weird corrosion on them near the bushings. No matter, put new Showa bling on for a fresh look. Wish coloring was more consistent between the two, but ya get what ya get with these. Did bump up oil to 370, haven’t rode them yet. Forgot to add an oring on slide tube to track travel, was a late night on the install. Can’t bring myself to use a zip tie.  lol. May bust one apart and add it one of these days. 

Laced new hubs up to stock hoops, may do another set this fall with excels and use this set for backups, and run some Mx14s for spring mud. But for now I like 34s. Cut the ribs out of stock hubs and may have them ceracoated, but the billet hubs look so much better. . Not much of a weight difference which was surprising. 

Loving the oversized front rotor and Nissan setup. 

Back to stock gearing, but did chop a link out of the chain. 

Running pc clamps which have a stiffer feel which I prefer. 

Previous gen water spout to remove the stock atrocity. 

Added pc water pump.  Zero noticeable difference but looks kinda cool. 

Overall good bike, but prefer my yz250 as it’s more playful.  I do plan to add a bit of cmt carbon bling and then probably focus on building a fresh yz smoker because the current steed has insane hours on it  


IMG 7683 2.jpeg?VersionId=dF1nmWcpeYSpsKw.9AIMG 7675 1IMG 7618 1IMG 7616IMG 7613 3IMG 7614 2.jpeg?VersionId=JGyoNsqUtseJxHLMbe.mxdu7uIMG 7615 1.jpeg?VersionId=rR dCbDQ0Zdkxu1RMWZYZ8DJCP8 S

IMG 7396.png?VersionId=vT7apudvIMG 7393 1


 

12
Golfnut721
Posts
38
Joined
8/31/2024
Location
HELTONVILLE, IN, USA
9/30/2025 7:11am

Anyone drill the stock motor mounts to soften the feel?

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