Kawasaki is bringing the two stroke back!

6/3/2026 7:49pm
Did you go with the x? I was going back and fourth but needed to make a decision on which one as the dealer said the...

Did you go with the x? I was going back and fourth but needed to make a decision on which one as the dealer said the rep told him they’re going cut off pre orders fast as they got hit with a lot of people putting Deposit down yesterday and today and the bike is selling fast . All my friends now ride trails now as we’re older so I ended up going with the x. And I’m sure if I do want to ride a track the x will still be pretty good for a old guy  

I ordered the X. My happy place is in the woods.

Already working on my day one mods list. Rear tubliss, front mousse, Renthal 999 (crossbar), Enduro Engineering bark busters. Already have everything except the bark busters in my garage.

Also going to grease the linkage (haven’t done that in a long time since my KTM is PDS) and steering stem before I ride it. 

It’s going to be a long 6 month wait but I’m very excited!

21
Gravel
Posts
1831
Joined
2/22/2014
Location
Ridgecrest, CA US
6/3/2026 8:22pm

Including the flat-black silencer? 🤔 Talk about retro!

😄

Got me there, I’d run a bare PC pipe and either a shorty or a SA silencer, depending on where I’m at. 

But damn, that’s a good looking scooter..

3
Village Idiot
Posts
2479
Joined
5/19/2023
Location
MXoN - a term used by newbs, goobs and rubes, PW US
6/3/2026 9:37pm

Including the flat-black silencer? 🤔 Talk about retro!

😄

Gravel wrote:
Got me there, I’d run a bare PC pipe and either a shorty or a SA silencer, depending on where I’m at. But damn, that’s a good...

Got me there, I’d run a bare PC pipe and either a shorty or a SA silencer, depending on where I’m at. 

But damn, that’s a good looking scooter..

Agreed. 👍

I could even get along with that grey Gun Kote finish Kawasaki put on the pipes for years.

And there's just something about the green/blue that just works, like the RMs. Those yellow Zukes just look soooooo good with those blue accents. The blue makes the green and yellow pop - much, much nicer than black. 

4
Pop Shmoke
Posts
1845
Joined
6/17/2020
Location
Boston, MA US
6/4/2026 12:07am Edited Date/Time 6/4/2026 12:50am

Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get from the stock kx250 engine. They took a 2003 kx250, used the stock crank, and modified it for +4mm stroke. Then they bored out the stock cylinder and used a 74mm wiseco piston. That got them to 327cc. 
 

IMG 5827 0

https://dirtbikemagazine.com/kawasaki-kx327-two-stroke-project/


Listening to weeges interview with the kawi guy he said the vision is to create more models of 2 strokes in the future. I’m sure that means a kx250, because if you can go up to a 327 from the 250 then you can go back down with the same general motor with a different bore and stroke. Theres no way they didnt design this from the start with plans to be able to make different models from the same general package. The fact that its a 327 makes me think a kx250 would be the next move from here. 

5
1

The Shop

DadBod86
Posts
228
Joined
7/31/2022
Location
Pittsworth, QLD AU
Fantasy
6/4/2026 4:25am
Pop Shmoke wrote:
Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get...

Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get from the stock kx250 engine. They took a 2003 kx250, used the stock crank, and modified it for +4mm stroke. Then they bored out the stock cylinder and used a 74mm wiseco piston. That got them to 327cc. 
 

IMG 5827 0

https://dirtbikemagazine.com/kawasaki-kx327-two-stroke-project/


Listening to weeges interview with the kawi guy he said the vision is to create more models of 2 strokes in the future. I’m sure that means a kx250, because if you can go up to a 327 from the 250 then you can go back down with the same general motor with a different bore and stroke. Theres no way they didnt design this from the start with plans to be able to make different models from the same general package. The fact that its a 327 makes me think a kx250 would be the next move from here. 

I was picking that up out of what he was saying as well, maybe Santa will announce a 250 closer to Christmas??

1
6/4/2026 4:50am

WHAT

Wonder if this means they’ll be adding the “F” back to the four-stroke model names.

Huh, I was right, lol

4
teledeluxe
Posts
5
Joined
3/4/2024
Location
Muenchen DE
6/4/2026 5:36am
Gravel wrote:

Needs gold rims

-MAVERICK- wrote:
1000011334

Near perfect! 

For me it needs other graphics. They are not bad, but could be better...

2
soggy
Posts
8665
Joined
12/3/2018
Location
UT US
6/4/2026 6:45am
dn315 wrote:
They’re different, that’s like saying, Honda, Kawasaki, Suzuki, and Yamaha were copying each others engine designs back when 2 strokes were still at the forefront because...

They’re different, that’s like saying, Honda, Kawasaki, Suzuki, and Yamaha were copying each others engine designs back when 2 strokes were still at the forefront because they looked similar. The Japanese brands all looked similar but were different. Were you expecting a modern fuel injected Japanese 2 stroke to look like what they were developing 20 years ago? 😂

 IMG 5457 0IMG 5459 0IMG 5460 0IMG 5458 0.png?VersionId=Kw77eb38o Zynh0ft.vcpc

 

Andy7 wrote:
I find it funny that Kawasaki designed an engine from scratch and somehow ended up placing everything exactly were it is on the SX 300 engine...

I find it funny that Kawasaki designed an engine from scratch and somehow ended up placing everything exactly were it is on the SX 300 engine LOL. The cylinder head looks almost identical. The balancer could be placed elsewhere. Again, nothing wrong with that. But I think using a KTM as your base is pretty much saying "you guys have figured it out so good, that I have no other option but to copy you".

On the othee hand, look up a TM 300 engine, a Beta 300 RX one, etc. They all look different from each other. However even the tilt is the same on the SX and KX.

BTW: I can almost bet that you can take a 300 SX pipe and it would mount on the KX.

1000351400.jpg?VersionId=yHfcBANLydJ8hYdkzhTZ44J6Ila1000351401.png?VersionId=up5n68mwHZVZF5DIOrQ

I guarantee you are wrong about the pipe

3
TAUTOG
Posts
1624
Joined
1/27/2023
Location
Mohrsville, PA US
6/4/2026 6:59am
Gravel wrote:

Needs gold rims

-MAVERICK- wrote:
1000011334

Make the blue, purple and I'm in!

3
BoxcarWilly
Posts
1163
Joined
10/5/2023
Location
Thunder Bay, ON CA
6/4/2026 7:01am

I'm hoping to go to the ISDE in 2027. This thing would probably rip through some Welsh mud bogs...

3
280driver
Posts
873
Joined
3/22/2017
Location
VA US
6/4/2026 7:26am
Andy7 wrote:
Now that it finally is out, the only thing that amazes me is how, in the recent years, Japan has had no shame at all copying...

Now that it finally is out, the only thing that amazes me is how, in the recent years, Japan has had no shame at all copying KTM (because this is more than inspiration, it is a copy). First it was the hydro clutch with a belleville wahser, no tool aribox, Brembo brakes, etc. Now, the engine looks the same as the KTM 300, they even have a nickel plated pipe instead of a black painted one. I am not hating at all, I am simply amazed by them doing this, because we usually call them stubborn, and "doing things the way they have always been done".

Who gives a shit.  

2
2
soggy
Posts
8665
Joined
12/3/2018
Location
UT US
6/4/2026 7:31am
Andy7 wrote:
Now that it finally is out, the only thing that amazes me is how, in the recent years, Japan has had no shame at all copying...

Now that it finally is out, the only thing that amazes me is how, in the recent years, Japan has had no shame at all copying KTM (because this is more than inspiration, it is a copy). First it was the hydro clutch with a belleville wahser, no tool aribox, Brembo brakes, etc. Now, the engine looks the same as the KTM 300, they even have a nickel plated pipe instead of a black painted one. I am not hating at all, I am simply amazed by them doing this, because we usually call them stubborn, and "doing things the way they have always been done".

280driver wrote:

Who gives a shit.  

new dirt bike still looks like dirt bike.  copy-cats!

3
Coach529
Posts
402
Joined
4/1/2008
Location
Coeur d'Alene, ID US
6/4/2026 7:46am
Pop Shmoke wrote:
Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get...

Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get from the stock kx250 engine. They took a 2003 kx250, used the stock crank, and modified it for +4mm stroke. Then they bored out the stock cylinder and used a 74mm wiseco piston. That got them to 327cc. 
 

IMG 5827 0

https://dirtbikemagazine.com/kawasaki-kx327-two-stroke-project/


Listening to weeges interview with the kawi guy he said the vision is to create more models of 2 strokes in the future. I’m sure that means a kx250, because if you can go up to a 327 from the 250 then you can go back down with the same general motor with a different bore and stroke. Theres no way they didnt design this from the start with plans to be able to make different models from the same general package. The fact that its a 327 makes me think a kx250 would be the next move from here. 

Interesting.

So 74mm bore and 76mm stroke potentially on the KX 327. 

For reference Beta 350 is 78mm x 73.6mm

Tom Morgan 315 is 72mm x 77mm

Pop Shmoke
Posts
1845
Joined
6/17/2020
Location
Boston, MA US
6/4/2026 8:11am Edited Date/Time 6/4/2026 8:12am
Pop Shmoke wrote:
Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get...

Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get from the stock kx250 engine. They took a 2003 kx250, used the stock crank, and modified it for +4mm stroke. Then they bored out the stock cylinder and used a 74mm wiseco piston. That got them to 327cc. 
 

IMG 5827 0

https://dirtbikemagazine.com/kawasaki-kx327-two-stroke-project/


Listening to weeges interview with the kawi guy he said the vision is to create more models of 2 strokes in the future. I’m sure that means a kx250, because if you can go up to a 327 from the 250 then you can go back down with the same general motor with a different bore and stroke. Theres no way they didnt design this from the start with plans to be able to make different models from the same general package. The fact that its a 327 makes me think a kx250 would be the next move from here. 

Coach529 wrote:

Interesting.

So 74mm bore and 76mm stroke potentially on the KX 327. 

For reference Beta 350 is 78mm x 73.6mm

Tom Morgan 315 is 72mm x 77mm

Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else in the thread said its a 76mm stroke so therefore its def a 74mm piston. Its a bit undersquare so its gonna be torquey. 

2
sandman768
Posts
8028
Joined
3/21/2014
Location
Saratoga Springs, NY US
6/4/2026 8:20am

Word on street is MXA already ordered +1 tooth rear sprocket for glen helens massive hills

14
OleTex2
Posts
566
Joined
8/12/2021
Location
Central, TX US
Fantasy
6/4/2026 8:33am
Pop Shmoke wrote:
Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get...

Apparently dirtbike magazine was the first to build a kx327. The fact that they also picked that number must mean thats the biggest you could get from the stock kx250 engine. They took a 2003 kx250, used the stock crank, and modified it for +4mm stroke. Then they bored out the stock cylinder and used a 74mm wiseco piston. That got them to 327cc. 
 

IMG 5827 0

https://dirtbikemagazine.com/kawasaki-kx327-two-stroke-project/


Listening to weeges interview with the kawi guy he said the vision is to create more models of 2 strokes in the future. I’m sure that means a kx250, because if you can go up to a 327 from the 250 then you can go back down with the same general motor with a different bore and stroke. Theres no way they didnt design this from the start with plans to be able to make different models from the same general package. The fact that its a 327 makes me think a kx250 would be the next move from here. 

Coach529 wrote:

Interesting.

So 74mm bore and 76mm stroke potentially on the KX 327. 

For reference Beta 350 is 78mm x 73.6mm

Tom Morgan 315 is 72mm x 77mm

Pop Shmoke wrote:
Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else...

Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else in the thread said its a 76mm stroke so therefore its def a 74mm piston. Its a bit undersquare so its gonna be torquey. 

Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming review. 

I’m sure Mitch Payton is already working on one. 

1
6/4/2026 8:37am
Coach529 wrote:

Interesting.

So 74mm bore and 76mm stroke potentially on the KX 327. 

For reference Beta 350 is 78mm x 73.6mm

Tom Morgan 315 is 72mm x 77mm

Pop Shmoke wrote:
Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else...

Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else in the thread said its a 76mm stroke so therefore its def a 74mm piston. Its a bit undersquare so its gonna be torquey. 

OleTex2 wrote:
Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming...

Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming review. 

I’m sure Mitch Payton is already working on one. 

Bore is larger than stroke is over square. But I’m actually impressed you’re aware of the concept. I’ve always been a fan of square, because I think they’re the best all over. Undersquare for grunt, oversquare to rev. 

3
1
TeamGreen
Posts
36914
Joined
11/25/2008
Location
Thru-out, CA US
6/4/2026 9:40am

Anyone take the time to realize -why- it took so long for this bike to “go public”…? 

1
2
6/4/2026 9:50am
TeamGreen wrote:

Anyone take the time to realize -why- it took so long for this bike to “go public”…? 

That's good because they were taking time to work out bugs

2
chuckie108
Posts
823
Joined
2/8/2012
Location
Mira Loma, CA US
6/4/2026 10:03am
Pop Shmoke wrote:
Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else...

Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else in the thread said its a 76mm stroke so therefore its def a 74mm piston. Its a bit undersquare so its gonna be torquey. 

OleTex2 wrote:
Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming...

Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming review. 

I’m sure Mitch Payton is already working on one. 

MoogenKen wrote:
Bore is larger than stroke is over square. But I’m actually impressed you’re aware of the concept. I’ve always been a fan of square, because I...

Bore is larger than stroke is over square. But I’m actually impressed you’re aware of the concept. I’ve always been a fan of square, because I think they’re the best all over. Undersquare for grunt, oversquare to rev. 

Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then in the 80's things were generally square (kudos to Honda, they figured this out by 1981 and is part of why CR250's ruled the 80's). By the 90's most the OE's figured it out. The only oversquare off-road 2 strokes you'll see these days are either poorly designed or are hamstrung by some design parameter that can't be moved. Part of why this should be a really interesting machine- should be a clean sheet design always intended to be this displacement. As opposed to the 300sx, Beta 350, BRC500's etc. which are generally trying to make a big bore out of a 250 lower end.  

2
6/4/2026 10:23am
chuckie108 wrote:
Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then...

Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then in the 80's things were generally square (kudos to Honda, they figured this out by 1981 and is part of why CR250's ruled the 80's). By the 90's most the OE's figured it out. The only oversquare off-road 2 strokes you'll see these days are either poorly designed or are hamstrung by some design parameter that can't be moved. Part of why this should be a really interesting machine- should be a clean sheet design always intended to be this displacement. As opposed to the 300sx, Beta 350, BRC500's etc. which are generally trying to make a big bore out of a 250 lower end.  

I’m not claiming to be Smokey Yunick nor Mitch Payton, but I’ll just leave this here:

Under-square engines (which have a smaller bore than stroke) naturally produce more torque at lower RPMs, while over-square engines (larger bore than stroke) are designed to rev higher and make more horsepower. [1, 2]
Here is a breakdown of why this happens and what it means for performance:
 
Under-Square Engines (Long-Stroke)
  • Design: The cylinder is narrower, but the piston travels a longer distance.
  • Why it makes torque: The longer stroke creates a larger leverage arm on the crankshaft (like using a longer wrench), which generates high twisting force (torque) at lower engine speeds. [1, 2, 3]
  • Characteristics: Excellent for pulling, towing, or daily driving where you need immediate power off the line. Because the piston has to travel further, these engines have higher piston speeds and cannot safely rev as high. [1, 2]
 
Over-Square Engines (Short-Stroke)
  • Design: The cylinder bore is wider, and the piston does not have to travel as far up and down. [1, 2]
  • Why it makes horsepower: Because the stroke is short, the piston doesn't travel as far per rotation, resulting in lower piston speeds. This allows the engine to safely reach much higher RPMs. Since horsepower is a function of torque multiplied by RPM, the ability to spin much faster allows these engines to produce higher peak horsepower. [1, 2, 3]
  • Characteristics: Ideal for sports cars and motorcycles. They generally feature larger valves (which improves airflow at high speeds) but tend to have less low-end grunt compared to under-square engines. [1, 2]
1
2
OleTex2
Posts
566
Joined
8/12/2021
Location
Central, TX US
Fantasy
6/4/2026 10:37am
Pop Shmoke wrote:
Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else...

Yep thats what I’m seeing, stock 2003 kx250 is a 72mm stroke so +4 is 76 and the 74mm wiseco piston got to 327. Someone else in the thread said its a 76mm stroke so therefore its def a 74mm piston. Its a bit undersquare so its gonna be torquey. 

OleTex2 wrote:
Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming...

Yeah the “stroker” under square 2T engines are beasts. Lots of power throughout. This one is on the small side, so I’m interested in the upcoming review. 

I’m sure Mitch Payton is already working on one. 

MoogenKen wrote:
Bore is larger than stroke is over square. But I’m actually impressed you’re aware of the concept. I’ve always been a fan of square, because I...

Bore is larger than stroke is over square. But I’m actually impressed you’re aware of the concept. I’ve always been a fan of square, because I think they’re the best all over. Undersquare for grunt, oversquare to rev. 

Thank you. I like square engines too. 

Maybe I mis-read it, but isn’t the stroke larger (longer) than the bore on this 327? Making it under square? I may be confusing myself at this point lol

 

1
6/4/2026 10:46am Edited Date/Time 6/4/2026 10:48am
OleTex2 wrote:
Thank you. I like square engines too. Maybe I mis-read it, but isn’t the stroke larger (longer) than the bore on this 327? Making it under square...

Thank you. I like square engines too. 

Maybe I mis-read it, but isn’t the stroke larger (longer) than the bore on this 327? Making it under square? I may be confusing myself at this point lol

 

Bore bigger than stroke, over square. 

Stroke bigger than bore is undersquare. 

Think about it this way, Harley’s are notoriously undersquare. Why they’re all grunt off the bottom. 

Yes Sir, I’ve got to stop and think about it. Then I’ll start doing equations, trying to figure out how, when, and why 5252 happens. Yep, tune myself right out of a race! 🤣🤣🤣

Borexborexstrokex.7854

RCMXracing
Posts
891
Joined
8/10/2011
Location
N., TX US
6/4/2026 10:49am

From the last couple posts would it be accurate to say that the KX 327 engine will be gruntier, torquier than a KTM 300 SX?

If so good for offroad, may need some massaging to gain top end right? Lower compression, raising ports, mapping fuel and ignition, etc., or could it have more top end than a 300 SX just based on the configuration of ports, compression, ECU, all of it?

Either way 2 strokes are endlessly modifiable 

1
6/4/2026 11:20am
RCMXracing wrote:
From the last couple posts would it be accurate to say that the KX 327 engine will be gruntier, torquier than a KTM 300 SX?If so...

From the last couple posts would it be accurate to say that the KX 327 engine will be gruntier, torquier than a KTM 300 SX?

If so good for offroad, may need some massaging to gain top end right? Lower compression, raising ports, mapping fuel and ignition, etc., or could it have more top end than a 300 SX just based on the configuration of ports, compression, ECU, all of it?

Either way 2 strokes are endlessly modifiable 

Gotta be careful with the torque / low end grunt thing....what a lot of guys think is low end torque is really just engine inertia.  Look at a XR400, impossible to stall and sets the gold standard for low rpm, it's very undersquare relative to all it's peers....it has a HUGE flywheel, lots of reciprocating mass but has less torque than all the MX bikes that stall if you look at them wrong.

How this Kawi rides is really going to depend on a) where the power is produced but more importantly b) how much flywheel weight they've engineered into the bike.  I'm not exactly sure what to think about the 327, it's sorta aimed at the 'enduro' crowd but I bet it's more sim to a GNCC style bike akin to a KTM XC vs a XCW, the XCW would be more of a modern KDX.

A personal examples is I have a 2022 450 XCF and a 2023 450 XCFW, engines are almost identical, slightly different cams, slightly different comp ratio but the XCFW has a much heavier flywheel and stalls 10x less in tech.

Another extreme example was my Montessa trials bike - virtually impossible to stall off idle even though it had 1/2 the torque off idle as the 450's.

image 3156image 3155
2
chuckie108
Posts
823
Joined
2/8/2012
Location
Mira Loma, CA US
6/4/2026 12:18pm
chuckie108 wrote:
Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then...

Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then in the 80's things were generally square (kudos to Honda, they figured this out by 1981 and is part of why CR250's ruled the 80's). By the 90's most the OE's figured it out. The only oversquare off-road 2 strokes you'll see these days are either poorly designed or are hamstrung by some design parameter that can't be moved. Part of why this should be a really interesting machine- should be a clean sheet design always intended to be this displacement. As opposed to the 300sx, Beta 350, BRC500's etc. which are generally trying to make a big bore out of a 250 lower end.  

MoogenKen wrote:
I’m not claiming to be Smokey Yunick nor Mitch Payton, but I’ll just leave this here:Under-square engines (which have a smaller bore than stroke) naturally...

I’m not claiming to be Smokey Yunick nor Mitch Payton, but I’ll just leave this here:

Under-square engines (which have a smaller bore than stroke) naturally produce more torque at lower RPMs, while over-square engines (larger bore than stroke) are designed to rev higher and make more horsepower. [1, 2]
Here is a breakdown of why this happens and what it means for performance:
 
Under-Square Engines (Long-Stroke)
  • Design: The cylinder is narrower, but the piston travels a longer distance.
  • Why it makes torque: The longer stroke creates a larger leverage arm on the crankshaft (like using a longer wrench), which generates high twisting force (torque) at lower engine speeds. [1, 2, 3]
  • Characteristics: Excellent for pulling, towing, or daily driving where you need immediate power off the line. Because the piston has to travel further, these engines have higher piston speeds and cannot safely rev as high. [1, 2]
 
Over-Square Engines (Short-Stroke)
  • Design: The cylinder bore is wider, and the piston does not have to travel as far up and down. [1, 2]
  • Why it makes horsepower: Because the stroke is short, the piston doesn't travel as far per rotation, resulting in lower piston speeds. This allows the engine to safely reach much higher RPMs. Since horsepower is a function of torque multiplied by RPM, the ability to spin much faster allows these engines to produce higher peak horsepower. [1, 2, 3]
  • Characteristics: Ideal for sports cars and motorcycles. They generally feature larger valves (which improves airflow at high speeds) but tend to have less low-end grunt compared to under-square engines. [1, 2]

Sorry if I'm coming across as a know it all asshole- not my intent. Was just trying to share some knowledge. 

What you shared is all true- but that is mainly focused on 4 cycle engines. When you look at data about "engines", the default "engine" everyone assumes is the dominate 4 cycle format of course. Not our niche but common racing 2 strokes. 

The most important parameter to performance of any engine is volumetric efficiency. So while bore and stroke certainly have massive effects on power character and power band, they will still always be second to VE in terms of power output. 4 strokes intake ports are on the top of the cylinder, therefore oversquare engines allow more port area per cc to create more power. Conversely, 2 stroke intake ports are in the side of the cylinder, therefore slightly undersquare engines allow for more port area per cc to make power. This why a YZ250F and a YZ250, even though they are the same displacement and application, have wildly different B@S's. (66.4x72) vs (77x53.6) 

The point of all this, the new KX327 being undersquare is not an indication of it being designed to be "torquey", as pretty much all current hi-performance 2 strokes are undersquare. Port area and timing will more effect the style of power. I'm hoping it ends up somewhere around 79x72.6, which will indicate Kawi designed it with peak overall output in mind. No one has brought a purpose-built mid-size 2 stroke to market to compete head to head with 4 strokes, so this should be a really interesting proof of concept when it hits the track. 

6
6/4/2026 12:27pm Edited Date/Time 6/4/2026 12:28pm
chuckie108 wrote:
Sorry if I'm coming across as a know it all asshole- not my intent. Was just trying to share some knowledge. What you shared is all true-...

Sorry if I'm coming across as a know it all asshole- not my intent. Was just trying to share some knowledge. 

What you shared is all true- but that is mainly focused on 4 cycle engines. When you look at data about "engines", the default "engine" everyone assumes is the dominate 4 cycle format of course. Not our niche but common racing 2 strokes. 

The most important parameter to performance of any engine is volumetric efficiency. So while bore and stroke certainly have massive effects on power character and power band, they will still always be second to VE in terms of power output. 4 strokes intake ports are on the top of the cylinder, therefore oversquare engines allow more port area per cc to create more power. Conversely, 2 stroke intake ports are in the side of the cylinder, therefore slightly undersquare engines allow for more port area per cc to make power. This why a YZ250F and a YZ250, even though they are the same displacement and application, have wildly different B@S's. (66.4x72) vs (77x53.6) 

The point of all this, the new KX327 being undersquare is not an indication of it being designed to be "torquey", as pretty much all current hi-performance 2 strokes are undersquare. Port area and timing will more effect the style of power. I'm hoping it ends up somewhere around 79x72.6, which will indicate Kawi designed it with peak overall output in mind. No one has brought a purpose-built mid-size 2 stroke to market to compete head to head with 4 strokes, so this should be a really interesting proof of concept when it hits the track. 

First, not at all. I’m here for it! Old dogs and new tricks. While I’m espousing what I know to be true, I’m not opposed to learn that other things are also true. If that makes sense. 

I understand VE etc; and geek out on things like spark events. You nailed it though. Most of my “real world” experience actually relates to nasty NA, Nitrous, Turbo V8s. 

I’m currently building a 72x70


 

1
6/4/2026 12:56pm
chuckie108 wrote:
Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then...

Two stroke tech has been undersquare for decades now. It's about port area. Even modern 125's are undersquare. For comparison, my '78 YZ400 is 85x70. Then in the 80's things were generally square (kudos to Honda, they figured this out by 1981 and is part of why CR250's ruled the 80's). By the 90's most the OE's figured it out. The only oversquare off-road 2 strokes you'll see these days are either poorly designed or are hamstrung by some design parameter that can't be moved. Part of why this should be a really interesting machine- should be a clean sheet design always intended to be this displacement. As opposed to the 300sx, Beta 350, BRC500's etc. which are generally trying to make a big bore out of a 250 lower end.  

MoogenKen wrote:
I’m not claiming to be Smokey Yunick nor Mitch Payton, but I’ll just leave this here:Under-square engines (which have a smaller bore than stroke) naturally...

I’m not claiming to be Smokey Yunick nor Mitch Payton, but I’ll just leave this here:

Under-square engines (which have a smaller bore than stroke) naturally produce more torque at lower RPMs, while over-square engines (larger bore than stroke) are designed to rev higher and make more horsepower. [1, 2]
Here is a breakdown of why this happens and what it means for performance:
 
Under-Square Engines (Long-Stroke)
  • Design: The cylinder is narrower, but the piston travels a longer distance.
  • Why it makes torque: The longer stroke creates a larger leverage arm on the crankshaft (like using a longer wrench), which generates high twisting force (torque) at lower engine speeds. [1, 2, 3]
  • Characteristics: Excellent for pulling, towing, or daily driving where you need immediate power off the line. Because the piston has to travel further, these engines have higher piston speeds and cannot safely rev as high. [1, 2]
 
Over-Square Engines (Short-Stroke)
  • Design: The cylinder bore is wider, and the piston does not have to travel as far up and down. [1, 2]
  • Why it makes horsepower: Because the stroke is short, the piston doesn't travel as far per rotation, resulting in lower piston speeds. This allows the engine to safely reach much higher RPMs. Since horsepower is a function of torque multiplied by RPM, the ability to spin much faster allows these engines to produce higher peak horsepower. [1, 2, 3]
  • Characteristics: Ideal for sports cars and motorcycles. They generally feature larger valves (which improves airflow at high speeds) but tend to have less low-end grunt compared to under-square engines. [1, 2]
chuckie108 wrote:
Sorry if I'm coming across as a know it all asshole- not my intent. Was just trying to share some knowledge. What you shared is all true-...

Sorry if I'm coming across as a know it all asshole- not my intent. Was just trying to share some knowledge. 

What you shared is all true- but that is mainly focused on 4 cycle engines. When you look at data about "engines", the default "engine" everyone assumes is the dominate 4 cycle format of course. Not our niche but common racing 2 strokes. 

The most important parameter to performance of any engine is volumetric efficiency. So while bore and stroke certainly have massive effects on power character and power band, they will still always be second to VE in terms of power output. 4 strokes intake ports are on the top of the cylinder, therefore oversquare engines allow more port area per cc to create more power. Conversely, 2 stroke intake ports are in the side of the cylinder, therefore slightly undersquare engines allow for more port area per cc to make power. This why a YZ250F and a YZ250, even though they are the same displacement and application, have wildly different B@S's. (66.4x72) vs (77x53.6) 

The point of all this, the new KX327 being undersquare is not an indication of it being designed to be "torquey", as pretty much all current hi-performance 2 strokes are undersquare. Port area and timing will more effect the style of power. I'm hoping it ends up somewhere around 79x72.6, which will indicate Kawi designed it with peak overall output in mind. No one has brought a purpose-built mid-size 2 stroke to market to compete head to head with 4 strokes, so this should be a really interesting proof of concept when it hits the track. 

One of the issues the 2T's are going to have regardless of how much power they make (and being undersquare only exacerbates the issue) is useable RPM.  For equivalent HP, 2T has 3-4k less RPM which means it's generally going to produce more torque but useable RPM is a huge benefit to a 4T...you can get higher RPM out of a 2T but you start getting into shorter stroke engines that don't have the low end power needed.  I think for a 2T to really be competitive you need to have a substantial tech leap to make that happen.  All the cool stuff in the past, variable dimension exhaust pipes, rotary valves, water injection, etc. etc....I just don't see it with this 327, but WTF do I know (not much).

2
1
Pop Shmoke
Posts
1845
Joined
6/17/2020
Location
Boston, MA US
6/4/2026 12:59pm
OleTex2 wrote:
Thank you. I like square engines too. Maybe I mis-read it, but isn’t the stroke larger (longer) than the bore on this 327? Making it under square...

Thank you. I like square engines too. 

Maybe I mis-read it, but isn’t the stroke larger (longer) than the bore on this 327? Making it under square? I may be confusing myself at this point lol

 

MoogenKen wrote:
Bore bigger than stroke, over square. Stroke bigger than bore is undersquare. Think about it this way, Harley’s are notoriously undersquare. Why they’re all grunt off the bottom. Yes...

Bore bigger than stroke, over square. 

Stroke bigger than bore is undersquare. 

Think about it this way, Harley’s are notoriously undersquare. Why they’re all grunt off the bottom. 

Yes Sir, I’ve got to stop and think about it. Then I’ll start doing equations, trying to figure out how, when, and why 5252 happens. Yep, tune myself right out of a race! 🤣🤣🤣

Borexborexstrokex.7854

Youre both saying the exact same thing

1
TDC
Posts
390
Joined
8/4/2023
Location
HTown, TX US
6/4/2026 1:19pm Edited Date/Time 6/4/2026 1:22pm

If the 327 has the grunt of a carb'd 300, perhaps that would explain the plus 27cc. Yet will be smooth as butta', like the TBI's. 

Kawi really needs to not have the MX version need re-flash updates for an aggressive response. Although it's been reported that spicier jetting makes the Beetah 350 more tiring. Anyway, there needs to be enough to appease the ole BITD 500 boys.

3

Post a reply to: Kawasaki is bringing the two stroke back!

The Latest