New Built Kawasaki KX500AF

AJ
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Lowell, IN US

Since all the hype over Kawasaki releasing a new 2 stroke model..

Just a reminder we( Built500) have offered  modern 500 2 strokes for the last 27 years and counting Smile

 

You might dig pics of this one..

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JazzyJJ
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Nunya, WY US
6/29/2025 11:50am

That looks like the finest way to kill myself imaginable 

21
Flatliner
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CA
6/29/2025 11:51am

Any video reviews of these beauties?

2
kawasa84
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Flower Mound, TX US
6/29/2025 11:58am

Would be a blast to ride and send some heavy roost. Also would get a lot of looks at the track.

2
Zerofear66
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Anaheim, CA US
6/29/2025 12:12pm

Always beautiful  work AJ.

Well done sir

 

very-good
3

The Shop

SLAPAHO
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Newport Beach, CA US
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6/29/2025 12:13pm

Awesome!

I'd love to see what you could do with a 125... 

4
AJ
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6/29/2025 12:14pm
Flatliner wrote:
Any video reviews of these beauties?

Any video reviews of these beauties?

There's some yt vids out there, I have never done many..  I know mxa has one of our CR 125 250 500AF at Glen Helen last year..( and quite a few in years past)

I really should shoot some vid footage,just hard to find the time....

 

1
AJ
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6/29/2025 12:17pm
SLAPAHO wrote:

Awesome!

I'd love to see what you could do with a 125... 

Thank you!  I do build 125AFs.   I just get a lot more requests for 500s..

Smile

 

I actually just finished this one up and took photos yesterday... if guys are interested... I'd do a seperate post on it with details...

It's a CR144.

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vdrsnk04
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IL US
6/29/2025 12:17pm

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

11
AJ
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Lowell, IN US
6/29/2025 12:45pm
vdrsnk04 wrote:
Clean builds!But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve...

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

Thanks!!   

for what its worth 

The advatages of efi are mpst effective on 80cc up to about 250..with declining returns 

Coubterbskancing almost always details a 2 stroke.

Try to port or do whatever to a kdx220,it will never out perform a kx125 as example.

That doesn't mean it's a bad engine the kdx200 is fantastic for what it's intended for .

 

The powervalve on the kx500 is indeed archaic. 

Most 500s we build are cr500 engine based ,no power valve at all and really doesn't need one.

🤷‍♂️

Everyone has thoer own tastes, so thats whybwe have tons if various brands and models to choose from,thats a fsntastic thing.

 

as far as my demographic, typically they appreciate the modern lightness,feel handling, but also like the simplistic reliability and ease of maintenance odlf the CR500 engie ( or kx500)

3
Beeby
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Chicago, IL US
6/29/2025 12:50pm Edited Date/Time 6/29/2025 12:51pm

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

1
AJ
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929
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Lowell, IN US
6/29/2025 1:32pm
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

We offer 125 250 and 500.

The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds.  500s are available brand new from.us, for 27 years,that's longer than any Japanese pr euronpem made them.   And it's a nichemarket but we are fairly well known in it.

 250s and 125 are available from srveral regular oems at a lower price, so that's naturally going yo dampen our sales in those displacement.

 

I will say that one thing really surprised me is when I brought back the kdx200 in a new  modern chassis ( this was importantly prior to  ktm offering a 150 or 200 exc model)  I had very little demand for it. I honestly thought it would do really well as it was such a cool off road machine and handled better than any bike ever made 

( according to dirt rider and dirt bike mags) and it was a brand new production bike,every part.

Everyone loved it, but very very few ordered them. 

Currentl  it makes sense it would have limited sale  today, as there are oem.options,but back then there really wasn't anything out in that lightweight  offroad category ,a category the original kdx200 had absolutely dominated for years and kawasaki had sold  metric tons of them

Stuff like that is hard to predict  🤣

Anyway I still love building those,but noone orders them ha.

ADSC 0174.JPG?VersionId=oquig9IczYhCfa6AniagyOUSmbbY2dZaDSC 0194.JPG?VersionId=pUL4coGxWHv.VOdWV6mDb1kOKvfjufdb june 2012 cover 1Iii
11
vdrsnk04
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IL US
6/29/2025 1:33pm
vdrsnk04 wrote:
Clean builds!But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve...

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

AJ wrote:
Thanks!!   for what its worth The advatages of efi are mpst effective on 80cc up to about 250..with declining returns Coubterbskancing almost always details a 2 stroke.Try to...

Thanks!!   

for what its worth 

The advatages of efi are mpst effective on 80cc up to about 250..with declining returns 

Coubterbskancing almost always details a 2 stroke.

Try to port or do whatever to a kdx220,it will never out perform a kx125 as example.

That doesn't mean it's a bad engine the kdx200 is fantastic for what it's intended for .

 

The powervalve on the kx500 is indeed archaic. 

Most 500s we build are cr500 engine based ,no power valve at all and really doesn't need one.

🤷‍♂️

Everyone has thoer own tastes, so thats whybwe have tons if various brands and models to choose from,thats a fsntastic thing.

 

as far as my demographic, typically they appreciate the modern lightness,feel handling, but also like the simplistic reliability and ease of maintenance odlf the CR500 engie ( or kx500)

Oh I am positive you have a big market for exactly what you are building. Rightfully so, those are impressive machines. Just not for me, I think I have been spoiled by the new 2 stroke stuff haha.

AJ
Posts
929
Joined
4/1/2008
Location
Lowell, IN US
6/29/2025 1:34pm
vdrsnk04 wrote:
Clean builds!But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve...

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

AJ wrote:
Thanks!!   for what its worth The advatages of efi are mpst effective on 80cc up to about 250..with declining returns Coubterbskancing almost always details a 2 stroke.Try to...

Thanks!!   

for what its worth 

The advatages of efi are mpst effective on 80cc up to about 250..with declining returns 

Coubterbskancing almost always details a 2 stroke.

Try to port or do whatever to a kdx220,it will never out perform a kx125 as example.

That doesn't mean it's a bad engine the kdx200 is fantastic for what it's intended for .

 

The powervalve on the kx500 is indeed archaic. 

Most 500s we build are cr500 engine based ,no power valve at all and really doesn't need one.

🤷‍♂️

Everyone has thoer own tastes, so thats whybwe have tons if various brands and models to choose from,thats a fsntastic thing.

 

as far as my demographic, typically they appreciate the modern lightness,feel handling, but also like the simplistic reliability and ease of maintenance odlf the CR500 engie ( or kx500)

vdrsnk04 wrote:
Oh I am positive you have a big market for exactly what you are building. Rightfully so, those are impressive machines. Just not for me, I...

Oh I am positive you have a big market for exactly what you are building. Rightfully so, those are impressive machines. Just not for me, I think I have been spoiled by the new 2 stroke stuff haha.

Totally understand that! I feel the ktm300 is a really well rounded off road bike as example.

FGR01
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AZ US
Fantasy
6/29/2025 1:47pm
vdrsnk04 wrote:
Clean builds!But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve...

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

Lots of guys would like to ride a fuel injected, electronic power valve 2-stroke.  Including many that own a TBI KTM that won't run.  🤭

6
6/29/2025 2:02pm

If I ever wanted a 500AF, I know who I would want to get it from. The older I get, the less balls I have though

2
theraptur712
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Victoria, TX US
6/29/2025 2:23pm

Who needs a power valve to increase top end power or hit on a 500cc 2 stroke? Jesus.

LOL. Just use 2nd and 3rd on most mx tracks. 4th if you have big balls. 5th if the balls are brass.

6/29/2025 2:31pm
Who needs a power valve to increase top end power or hit on a 500cc 2 stroke? Jesus.LOL. Just use 2nd and 3rd on most mx...

Who needs a power valve to increase top end power or hit on a 500cc 2 stroke? Jesus.

LOL. Just use 2nd and 3rd on most mx tracks. 4th if you have big balls. 5th if the balls are brass.

I wanna ride the track you get use 5th on a 500. Or watch a rider who's good enough to use 5th on a 500 on any track

mxaniac
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Airway Heights, WA US
6/29/2025 10:05pm
AJ wrote:
Since all the hype over Kawasaki releasing a new 2 stroke model..Just a reminder we( Built500) have offered  modern 500 2 strokes for the last 27...

Since all the hype over Kawasaki releasing a new 2 stroke model..

Just a reminder we( Built500) have offered  modern 500 2 strokes for the last 27 years and counting Smile

 

You might dig pics of this one..

1000023810 01000023814100002382210000238211000023825

Looks gorgeous.  I'd  built one many years ago, but it wasn't a work of art like yours. Unfortunately it burned up in a fire in 2020.

1jm6o1 0.jpg?VersionId=mKOZWDbl3e2gmmMlTLwfc.gGG
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mx691
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Stockholm SE
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6/29/2025 10:27pm
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

AJ wrote:
We offer 125 250 and 500.The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds...

We offer 125 250 and 500.

The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds.  500s are available brand new from.us, for 27 years,that's longer than any Japanese pr euronpem made them.   And it's a nichemarket but we are fairly well known in it.

 250s and 125 are available from srveral regular oems at a lower price, so that's naturally going yo dampen our sales in those displacement.

 

I will say that one thing really surprised me is when I brought back the kdx200 in a new  modern chassis ( this was importantly prior to  ktm offering a 150 or 200 exc model)  I had very little demand for it. I honestly thought it would do really well as it was such a cool off road machine and handled better than any bike ever made 

( according to dirt rider and dirt bike mags) and it was a brand new production bike,every part.

Everyone loved it, but very very few ordered them. 

Currentl  it makes sense it would have limited sale  today, as there are oem.options,but back then there really wasn't anything out in that lightweight  offroad category ,a category the original kdx200 had absolutely dominated for years and kawasaki had sold  metric tons of them

Stuff like that is hard to predict  🤣

Anyway I still love building those,but noone orders them ha.

ADSC 0174.JPG?VersionId=oquig9IczYhCfa6AniagyOUSmbbY2dZaDSC 0194.JPG?VersionId=pUL4coGxWHv.VOdWV6mDb1kOKvfjufdb june 2012 cover 1Iii

I had a -89 and a -91 KDX 200. Awesome engines!

My dreambike once was that engine in a modern enduro chassie.

6/30/2025 7:02am
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

AJ wrote:
We offer 125 250 and 500.The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds...

We offer 125 250 and 500.

The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds.  500s are available brand new from.us, for 27 years,that's longer than any Japanese pr euronpem made them.   And it's a nichemarket but we are fairly well known in it.

 250s and 125 are available from srveral regular oems at a lower price, so that's naturally going yo dampen our sales in those displacement.

 

I will say that one thing really surprised me is when I brought back the kdx200 in a new  modern chassis ( this was importantly prior to  ktm offering a 150 or 200 exc model)  I had very little demand for it. I honestly thought it would do really well as it was such a cool off road machine and handled better than any bike ever made 

( according to dirt rider and dirt bike mags) and it was a brand new production bike,every part.

Everyone loved it, but very very few ordered them. 

Currentl  it makes sense it would have limited sale  today, as there are oem.options,but back then there really wasn't anything out in that lightweight  offroad category ,a category the original kdx200 had absolutely dominated for years and kawasaki had sold  metric tons of them

Stuff like that is hard to predict  🤣

Anyway I still love building those,but noone orders them ha.

ADSC 0174.JPG?VersionId=oquig9IczYhCfa6AniagyOUSmbbY2dZaDSC 0194.JPG?VersionId=pUL4coGxWHv.VOdWV6mDb1kOKvfjufdb june 2012 cover 1Iii

All for what, $25,000?

motomike137
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Fenton, MI US
6/30/2025 7:13am
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

If you know how to ride them they are just big ol teddy bears Wink

4
motomike137
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Location
Fenton, MI US
6/30/2025 7:17am
Who needs a power valve to increase top end power or hit on a 500cc 2 stroke? Jesus.LOL. Just use 2nd and 3rd on most mx...

Who needs a power valve to increase top end power or hit on a 500cc 2 stroke? Jesus.

LOL. Just use 2nd and 3rd on most mx tracks. 4th if you have big balls. 5th if the balls are brass.

I wanna ride the track you get use 5th on a 500. Or watch a rider who's good enough to use 5th on a 500 on...

I wanna ride the track you get use 5th on a 500. Or watch a rider who's good enough to use 5th on a 500 on any track

It wasn't so much using 5th on a track as it was making these bikes well rounded for any type of riding. They make great off road weapons as well. Add a tooth to the front and a spark arrester and you have a northern Michigan fire trail and woods beast not to mention ice bike in the winter Smile

loftyair
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riverside, CA US
6/30/2025 7:54am

The KTM 200 and 380 in a new chassis would be sweet!

Gravel
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Ridgecrest, CA US
6/30/2025 12:57pm
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

If you know how to ride them they are just big ol teddy bears Wink

It’s the learning how to ride them part that can be painful, lol! My first 500 must have hated the sight of me, it threw me on the ground constantly for about a year. Then we came to an agreement that I’d be nicer to the throttle and it’d let me finish a ride without crashing. They really are easy to ride once you learn how, throttle control is the key..

Beautiful work, that KX would look amazing in my garage!

SEEMEFIRST
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Location
Arlington, TX US
6/30/2025 1:27pm
Beeby wrote:
That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked...

That looks awesome. I actually can’t believe you get so much demand for 500’s they are just so damn fast. I’d imagine a 250 that looked like that would sell well though, hey Kawi ;-)

AJ wrote:
We offer 125 250 and 500.The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds...

We offer 125 250 and 500.

The 500s put sell the others by a lot,but most of that is due to the custom nature of our builds.  500s are available brand new from.us, for 27 years,that's longer than any Japanese pr euronpem made them.   And it's a nichemarket but we are fairly well known in it.

 250s and 125 are available from srveral regular oems at a lower price, so that's naturally going yo dampen our sales in those displacement.

 

I will say that one thing really surprised me is when I brought back the kdx200 in a new  modern chassis ( this was importantly prior to  ktm offering a 150 or 200 exc model)  I had very little demand for it. I honestly thought it would do really well as it was such a cool off road machine and handled better than any bike ever made 

( according to dirt rider and dirt bike mags) and it was a brand new production bike,every part.

Everyone loved it, but very very few ordered them. 

Currentl  it makes sense it would have limited sale  today, as there are oem.options,but back then there really wasn't anything out in that lightweight  offroad category ,a category the original kdx200 had absolutely dominated for years and kawasaki had sold  metric tons of them

Stuff like that is hard to predict  🤣

Anyway I still love building those,but noone orders them ha.

ADSC 0174.JPG?VersionId=oquig9IczYhCfa6AniagyOUSmbbY2dZaDSC 0194.JPG?VersionId=pUL4coGxWHv.VOdWV6mDb1kOKvfjufdb june 2012 cover 1Iii

That KDX is sweet! Those were incredible bikes. Woods killers, but I always loved the 500s more.

Today? The KDX is looking like a better choice.

APLMAN99
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Tualatin, OR US
Fantasy
6/30/2025 1:35pm
vdrsnk04 wrote:
Clean builds!But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve...

Clean builds!


But, I don’t want a 2 stroke from 30 years ago. I would take that bike if it had a fuel injected, electronic power valve, counterbalanced 250 2 stroke though. 

AJ wrote:
Thanks!!   for what its worth The advatages of efi are mpst effective on 80cc up to about 250..with declining returns Coubterbskancing almost always details a 2 stroke.Try to...

Thanks!!   

for what its worth 

The advatages of efi are mpst effective on 80cc up to about 250..with declining returns 

Coubterbskancing almost always details a 2 stroke.

Try to port or do whatever to a kdx220,it will never out perform a kx125 as example.

That doesn't mean it's a bad engine the kdx200 is fantastic for what it's intended for .

 

The powervalve on the kx500 is indeed archaic. 

Most 500s we build are cr500 engine based ,no power valve at all and really doesn't need one.

🤷‍♂️

Everyone has thoer own tastes, so thats whybwe have tons if various brands and models to choose from,thats a fsntastic thing.

 

as far as my demographic, typically they appreciate the modern lightness,feel handling, but also like the simplistic reliability and ease of maintenance odlf the CR500 engie ( or kx500)

Always love seeing your creations and glad that you have been able to continue after Service Honda. I still get a little bit aggravated when I see people refer to other conversions as ‘AFs’ because that should only refer to yours!  

As for the vibration, it sounds like one of the things people like about the ‘new’ BRC YZ500 engine is the lack of heavy vibration. Is it that big of a difference and if so is there a way to work with the CR/KX engines to get the same effect?  

1
1
toomanykaws
Posts
506
Joined
4/1/2008
Location
Henderson, NV US
6/30/2025 1:48pm
Love my 500’s. Have had six at once. Still have four. And one AF I built.
Inferno
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388
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Laguna IC
6/30/2025 4:14pm

Nice builds, man! 😍

Joko
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Location
Haddam, CT US
Fantasy
6/30/2025 9:23pm

AJ, Do you build the KX500 with only the 19-23 model, or do you also offer the 24-25 model frame? Do you find the 19-23 frame turns better with the 500 in it than the 450 engine?

6/30/2025 10:17pm

This is what Prado has been looking for. 

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