KX450 steering stem bearings

NicNak
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998
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2/18/2019
Location
Palm Desert, CA US
Edited Date/Time 3/4/2021 11:00am
So I ride KX450s. I currently have a 2021 KX450, I’ve also had this same problem on the 19 & 20. The steering stem bearings last about a weekend (exaggerating) but they wear out super quickly.

Anybody have any tips or tricks on how to avoid this issue moving forward?

& for the love of God, yes I grease them for all the vitards that are going to ask.
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cmotodad
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1007
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12/18/2013
Location
Yorba Linda, CA US
3/2/2021 8:26pm
Hoping for an answer too. Go thru bearings way too fast.
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hititpind
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401
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2/27/2015
Location
UT US
3/2/2021 8:35pm
How can you tell when they go bad? Honest question
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Moto520
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Schaumburg, IL US
3/2/2021 8:48pm
I’m at 82 hours and they are fine. I did grease them and try my best not to direct spray the freaking thing
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Yeti831
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1/30/2020
Location
UT US
3/2/2021 9:37pm
Genuine question: did you ride it as is or grease everything up on delivery? And did you for sure flush everything up?

The Shop

coastie44
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559
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1/19/2013
Location
NorCal, CA US
3/2/2021 10:07pm
36hrs on my 17 and 19 are both sets are perfectly fine???
neysbo
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2005
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4/1/2008
Location
Edelstein, IL US
3/3/2021 4:41am
I think it is caused by water from power washing. Must get through the seal at the top , I wonder if can put some silicone around the seal at the top.
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KPS_46
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15
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11/30/2020
Location
NE, OH US
3/3/2021 5:08am
Get some of that motorex long term 2000 grease, have had good luck with it.
Zeke27G
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11/8/2011
Location
Ascot Park, CA US
3/3/2021 5:35am

38 hours on my 2019 and using Maxima grease without any issues.

And FWIW, I don't use a pressure washer, just Mr. Clean Multi-Purpose cleaner and one of those fire hydrant style garden hose nozzles.
pete24
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2733
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10/20/2011
Location
Marlborough, MA US
3/3/2021 6:54am
put two sets in my 17 each at 35 hrs, greased when new obviously, my 20 has 50 hrs greased them again at 25hrs probably change them before this season starts,
be glad you dont have a yamaha they burn threw fork seals, front wheel bearings and steering bearings
50dippin
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361
Joined
10/4/2009
Location
Los Angeles, CA US
3/3/2021 12:19pm
Mine have lasted just as long as my old yz450, I seem to get about 1.5 years out of them. I do try and limit pressure washing that area and that seems to help. Its always the lower bearing since water will pool in that area after a wash.
loftyair
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2899
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7/3/2009
Location
riverside, CA US
3/3/2021 12:24pm
Be sure the races are good before just a bearing swap. Bad races will ruin bearings in a day.
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zehn
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Location
Anchorage, AK US
3/3/2021 12:28pm
hititpind wrote:
How can you tell when they go bad? Honest question
Was wondering the same thing? Maybe these guys have freakish attention to detail?
3/3/2021 12:36pm
hititpind wrote:
How can you tell when they go bad? Honest question
zehn wrote:
Was wondering the same thing? Maybe these guys have freakish attention to detail?
move bars side to side on stand easiest way to tell, will be notchy feeling or even sum play when moving front forks back & forward. most wont notice when you are riding though
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DB97
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1179
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7/28/2016
Location
Orlando, FL US
3/3/2021 4:33pm
I think these frames hold water or moisture. If you don’t have the bottom skid plate on there’s open holes. I greased my 19 and let it sit in the garage for a few weeks. Took the clamps off to put my xtrigs back on and there was moisture on the stem. Didn’t ride or wash it at all. I’m in Florida so it worst case probably but still... also water tends to leak out of the frame when I load it up to a certain angle.
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Timo
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Location
Wichita, KS US
3/3/2021 5:25pm
pete24 wrote:
put two sets in my 17 each at 35 hrs, greased when new obviously, my 20 has 50 hrs greased them again at 25hrs probably change...
put two sets in my 17 each at 35 hrs, greased when new obviously, my 20 has 50 hrs greased them again at 25hrs probably change them before this season starts,
be glad you dont have a yamaha they burn threw fork seals, front wheel bearings and steering bearings
Stock fork seals on my yzfx only lasted 25 hours, so I'll give you that. Wheel bearings have over 50 hours on them and just greased for the 1st time. I've never had to replace steering stem bearings, and I've had 5 Yamaha's in the last 20 years.
MX369
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84
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1/25/2020
Location
Cape Girardeau, MO US
3/3/2021 6:42pm
ALL new bikes come with only about half a thimble of grease in the stem bearings, wheel bearings and rear suspension links. First thing when purchasibng a NEW bike is GREASE the hell out of it!
kkawboy14
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11486
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6/5/2015
Location
TX US
3/3/2021 6:43pm
I have ridden kx since 1982 and own a 2020 Kx450f I have never had to replace steering bearings in any bike.
Jbulz
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871
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3/29/2016
Location
Ithaca, NY US
3/4/2021 5:46am
Myself and 3 friends owed 2019 KX450s new. I know every one of us has had multiple steering stem bearing rusting issues. I personally did 4 sets in 2 seasons on my bike.

My first sign of rust on these bikes is when you take the bike off the stand after it sits for a few days the bars will be locked straight until you break them free. It's downhill quickly after that and they get extremely notchy, to the point where it can be pretty scary to ride, especially on rutted straights. I was surprised it would feel it while riding to be honest!

It looks to me like there is not an adequate seal between the upper inner race and the steering stem, so water runs down and rusts the lower bearing. I've also seen water run out of the bottom of the frame, even after the bike has sat for a week, so maybe that could be causing it too? Either way, no amount of grease will protect against that.

Side note... How come the guys who brag about not using a pressure washing are always from California? Whistling
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captmoto
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Rancho Cucamonga, CA US
3/4/2021 10:34am
neysbo wrote:
I think it is caused by water from power washing. Must get through the seal at the top , I wonder if can put some silicone...
I think it is caused by water from power washing. Must get through the seal at the top , I wonder if can put some silicone around the seal at the top.
How bad is your mud that you need to pressure wash behind the number plate? I use a hose and wash as much as I can first then Shout laundry pre-treater to get the rest of it. I only used a low power pressure washer when things here are really bad or after riding a clay track that dries like mortar on the bike.
I heard just recently that Yamahas (?) have a thicker seal on their bearings. Maybe research that.
Jbulz
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Location
Ithaca, NY US
3/4/2021 11:00am
neysbo wrote:
I think it is caused by water from power washing. Must get through the seal at the top , I wonder if can put some silicone...
I think it is caused by water from power washing. Must get through the seal at the top , I wonder if can put some silicone around the seal at the top.
captmoto wrote:
How bad is your mud that you need to pressure wash behind the number plate? I use a hose and wash as much as I can...
How bad is your mud that you need to pressure wash behind the number plate? I use a hose and wash as much as I can first then Shout laundry pre-treater to get the rest of it. I only used a low power pressure washer when things here are really bad or after riding a clay track that dries like mortar on the bike.
I heard just recently that Yamahas (?) have a thicker seal on their bearings. Maybe research that.
I purposely avoid the stem area and still have the issue.

This was my first race on my 2021 😬

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Mperez_43
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Sant Celoni, Barcelona ES
2/5/2025 10:33am
Jbulz wrote:
Myself and 3 friends owed 2019 KX450s new. I know every one of us has had multiple steering stem bearing rusting issues. I personally did 4...
Myself and 3 friends owed 2019 KX450s new. I know every one of us has had multiple steering stem bearing rusting issues. I personally did 4 sets in 2 seasons on my bike.

My first sign of rust on these bikes is when you take the bike off the stand after it sits for a few days the bars will be locked straight until you break them free. It's downhill quickly after that and they get extremely notchy, to the point where it can be pretty scary to ride, especially on rutted straights. I was surprised it would feel it while riding to be honest!

It looks to me like there is not an adequate seal between the upper inner race and the steering stem, so water runs down and rusts the lower bearing. I've also seen water run out of the bottom of the frame, even after the bike has sat for a week, so maybe that could be causing it too? Either way, no amount of grease will protect against that.

Side note... How come the guys who brag about not using a pressure washing are always from California? Whistling

Did you at some point find the way to solve this issue? Dealing with it constantly on my 23' KX450...

 

Thanks !

Kyle978
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10/7/2013
Location
Dirt, NM US
2/5/2025 10:49am
Mperez_43 wrote:

Did you at some point find the way to solve this issue? Dealing with it constantly on my 23' KX450...

 

Thanks !

They just let water in more than other brands from what I can tell, I have to replace mine every 20 hours or so. I pack the shit out of them with grease, but water still gets in. 

Only solution is to disassemble the front end after you wash to get rid of moisture (and who the hell is going to do that?), or just buy a couple bearings and change them out every so often. I just use the cheap aftermarket ones, OEM doesn't last any longer. 

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Mperez_43
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2
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2/5/2025
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Sant Celoni, Barcelona ES
2/5/2025 11:01am
Mperez_43 wrote:

Did you at some point find the way to solve this issue? Dealing with it constantly on my 23' KX450...

 

Thanks !

Kyle978 wrote:
They just let water in more than other brands from what I can tell, I have to replace mine every 20 hours or so. I pack...

They just let water in more than other brands from what I can tell, I have to replace mine every 20 hours or so. I pack the shit out of them with grease, but water still gets in. 

Only solution is to disassemble the front end after you wash to get rid of moisture (and who the hell is going to do that?), or just buy a couple bearings and change them out every so often. I just use the cheap aftermarket ones, OEM doesn't last any longer. 

We're at the same point, 20 hours in only is crazy, if I find out about a better way than replacing them that often i'll post it, for now i'll have to stick to that...

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bvm111
Posts
10076
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7/1/2008
Location
Las Vegas, NV US
2/5/2025 11:15am

I have had that issue on every KX i have owned… I service my head bearings every 10 hours (excessive i know, but i’m retired and bored) and it’s still pretty nasty in there  after that low of hours. 

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wwdiii
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2533
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4/15/2019
Location
League City, TX US
2/7/2025 6:33am

I’m no grease/lubricant expert by any means.  All I know is what I learned  working all those years on instrumentation and control devices, refineries and other industrial facilities.  We used many different oils and grease on mechanical devices.

With that said when I pulled the steering head off my 24 KX450 I picked up right after Christmas.  It was lubed with a crystal clean grease, it was slick as snot too.   Probably a high end synthetic grease, it was good grease best I could tell.  

As I recall the clear synthetic lubricants are used for corrosion resistance.  Where a grease like high end red tacky grease or Maxima grease has better lubricantion properties, but lack corrosion resistance of a these high end clear synthetic lubricants.  I thought about buying some clear synthetic lube just to have some, Amazon sells it but it’s higher then cats ass.  

My point is, Kawasaki may have an issue with steering bearing corrosion.  Therefore type lube they use on steering bearings.  Just a guess on my part.   I lubed my steering head with Maxima, it will do just fine for my purpose. 

 

Sandusky26
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3385
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7/28/2021
Location
Eastern, NC US
2/7/2025 6:41am

I think the problem is all the holes in the frame collect water and condensation is the problem. I think the more humid the climate the worse it is.

I can't wash a KX450 and not have a little water/condensation in the bearing. The bottom bearing is usually worse, don't make sense if water runs down.

The best thing I've done is mix anti seize in my grease and grease every 10 hours. Leave the front end together and drop it to grease lower bearing doesn't take long.

This is my hypothesis from my scientific data collected from 2 KX450's ridden by a construction worker.

wwdiii
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2533
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Location
League City, TX US
2/7/2025 10:01am
Sandusky26 wrote:
I think the problem is all the holes in the frame collect water and condensation is the problem. I think the more humid the climate the...

I think the problem is all the holes in the frame collect water and condensation is the problem. I think the more humid the climate the worse it is.

I can't wash a KX450 and not have a little water/condensation in the bearing. The bottom bearing is usually worse, don't make sense if water runs down.

The best thing I've done is mix anti seize in my grease and grease every 10 hours. Leave the front end together and drop it to grease lower bearing doesn't take long.

This is my hypothesis from my scientific data collected from 2 KX450's ridden by a construction worker.

Mixing anti size sounds like a good idea.  I never thought of that.  

wwdiii
Posts
2533
Joined
4/15/2019
Location
League City, TX US
2/7/2025 10:18am
Sandusky26 wrote:
I think the problem is all the holes in the frame collect water and condensation is the problem. I think the more humid the climate the...

I think the problem is all the holes in the frame collect water and condensation is the problem. I think the more humid the climate the worse it is.

I can't wash a KX450 and not have a little water/condensation in the bearing. The bottom bearing is usually worse, don't make sense if water runs down.

The best thing I've done is mix anti seize in my grease and grease every 10 hours. Leave the front end together and drop it to grease lower bearing doesn't take long.

This is my hypothesis from my scientific data collected from 2 KX450's ridden by a construction worker.

Also never thought about dropping the front with everting still together to get to the lower beating.  But lots of things I’ve never thought of lol.

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kawasa84
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1717
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Location
Flower Mound, TX US
2/7/2025 10:21am
kkawboy14 wrote:
I have ridden kx since 1982 and own a 2020 Kx450f I have never had to replace steering bearings in any bike.

Been on Green since 1979. Currently have a stable of 6 KX's. I doubt anyone on here would believe me, but I have an '05 KX250 2 stroke with over 900 hours. It was my main bike for 17 years!

Impeccably maintained, but I never have had to change the stem bearings. I've greased them at least twice per year every year. But I've wore out and replaced parts on that bike that most would never think can wear out. I still ride it frequently. Full Race Tech suspension and the bike settles into corners like a dream. 

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