Athena CRF450 reduction kit?

FGR01
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FGR01
Edited Date/Time 1/21/2022 2:42pm
Saw this posted. Athena kit that reduces a CRF450 to 413cc.

Anyone have any info or experience with this?

Link in case you can't see the embed below: https://www.instagram.com/p/CYey9afPTMB/

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LouisianaMotocross 1/12/2022 10:42am
1/12/2022 10:42am Edited Date/Time 1/12/2022 10:42am
Is the link not working for anyone else? I ask because the old work computer blocks stuff sometimes.
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RF145
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RF145 1/12/2022 1:19pm
1/12/2022 1:19pm
LouisianaMotocross wrote:
Is the link not working for anyone else? I ask because the old work computer blocks stuff sometimes.
Link worked for me.
FGR01
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FGR01 1/12/2022 5:17pm
1/12/2022 5:17pm
HenryA wrote:
I believe that it's the same kit that is used on the CRF400RX. https://www.redmoto.it/?prodotto-moto=crf-400rx-enduro-2021&lang=en [IMG]https://www.redmoto.it/wp-content/uploads/HONDA_CRF400RX_PRINCIPALE.png[/IMG]
I believe that it's the same kit that is used on the CRF400RX.
https://www.redmoto.it/?prodotto-moto=crf-400rx-enduro-2021&lang=en


Appears you are right! Here's the kit itself:

https://www.redmotousa.com/product-page/400rx-engine-kit

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TeamGreen
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TeamGreen 1/12/2022 5:29pm
1/12/2022 5:29pm
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
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cmotodad
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cmotodad 1/12/2022 8:39pm
1/12/2022 8:39pm
Or make it a 488 that mellows and smooths out the power. Super easy to ride
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bents
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bents 1/12/2022 8:40pm
1/12/2022 8:40pm
Great idea-Will look forward to seeing how this works. My 99 YZ400F had such an amazingly easy power to use. So fun and not threatening.
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bite_the_curb 1/12/2022 9:28pm
1/12/2022 9:28pm
wasnt carolios factory sx-f essentially a 400?
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Kennyfreemoney 1/12/2022 9:31pm
1/12/2022 9:31pm Edited Date/Time 1/12/2022 9:33pm
Honest question, what would be the benefits of this vs a 350? Is it going to be much power difference? Or is it for someone that wants specifically a Honda “350”?
Pirate421
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Pirate421 1/13/2022 3:49am
1/13/2022 3:49am
Kennyfreemoney wrote:
Honest question, what would be the benefits of this vs a 350? Is it going to be much power difference? Or is it for someone that...
Honest question, what would be the benefits of this vs a 350? Is it going to be much power difference? Or is it for someone that wants specifically a Honda “350”?
If you look at their site they also make a 300 kit for the 250 so I’m not sure which one would be their “350” equivalent. They do make it sound on their website that these kits are available as an OEM option if I read it right. Very cool if so.
luke11
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luke11 1/13/2022 4:17am
1/13/2022 4:17am
I would love a 300. Even a 350 is slightly too much but a 250 is slightly not enough
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Richy
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Richy 1/13/2022 4:44am
1/13/2022 4:44am Edited Date/Time 1/13/2022 4:45am
bite_the_curb wrote:
wasnt carolios factory sx-f essentially a 400?
I may be wrong, but although there were rumours of that I believe they (KTM and/or the FIM) tore it down a couple of times and it was a 350, then he switched to a full bore 450.

With how in-bed KTM and Luongo are, and how the 350 was a shared vision, who knows if either of them would tell the truth anyway, but likewise why lie.

Either way it is certainly believable a young Cairolli and factory 350 would be totally capable.
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Richy
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Richy 1/13/2022 4:45am
1/13/2022 4:45am
luke11 wrote:
I would love a 300. Even a 350 is slightly too much but a 250 is slightly not enough
Kind of agree, at least in the UK, I'd love a TM 300 4 stroke... And matching 2 stroke haha
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luke11
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luke11 1/13/2022 4:52am
1/13/2022 4:52am
luke11 wrote:
I would love a 300. Even a 350 is slightly too much but a 250 is slightly not enough
Richy wrote:
Kind of agree, at least in the UK, I'd love a TM 300 4 stroke... And matching 2 stroke haha
Yea I think Americans prefer the 350/450 because the tracks are so much bigger/faster. I 100% believe for the tracks we have here a 250 is quicker than a 450 90% of the time. Even more so when you factor in the energy loss by riding a 450
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jleews6
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jleews6 1/13/2022 7:10am
1/13/2022 7:10am
I think this is a great idea. I have a 250RX and my son has a 450RX and my bike needs more but his is just to much so this might be the answer to making a 450 easier to ride for off road. My other son has a 450RL and that motor is perfect for off road hair scramble type riding.
RCMXracing
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RCMXracing 1/13/2022 7:51am
1/13/2022 7:51am
Following…
Obv lose some torque, but gain quicker revs right? Gotta be a positive somewhere or why shrink down the displacement?
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WDSRCR
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WDSRCR 1/13/2022 10:23am
1/13/2022 10:23am
A friend is supposed to receive his Redmoto 400RX kit this week. I will be trying it out in SC before the first NEPG in a few weeks. I think it will be just about perfect. I have rode the 300RX and it's punchy but it seems to rev out too quickly. I think the mellowed down 400 could be the way to go.
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PFitzG38
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PFitzG38 1/13/2022 10:36am
1/13/2022 10:36am Edited Date/Time 1/13/2022 10:44am
The best mod I ever did to my crf450 was a big bore with a flywheel wt. much easier to hang onto and I could pull holeshots basically whenever I felt like it…..and you want to sleeve it down? Yeah, NO!!
The only bike that should be sleeved is a CR125 down to a 100 - 40 yrs ago.

That being said I would love to find a big bore jug for my KTM 450. I haven’t pulled a holie since I bought it, I loved the power advantage and confidence a big bore gave me
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davis224
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davis224 1/13/2022 10:36am
1/13/2022 10:36am
bite_the_curb wrote:
wasnt carolios factory sx-f essentially a 400?
His Yamaha was
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bite_the_curb 1/13/2022 2:30pm
1/13/2022 2:30pm
feel like it couldnt be too hard to de-tune a 450 via ecu mapping or using one of those throttle cam things, flywheel weights and gearing

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H.E.penyypacker432 1/13/2022 2:58pm
1/13/2022 2:58pm
PFitzG38 wrote:
The best mod I ever did to my crf450 was a big bore with a flywheel wt. much easier to hang onto and I could pull...
The best mod I ever did to my crf450 was a big bore with a flywheel wt. much easier to hang onto and I could pull holeshots basically whenever I felt like it…..and you want to sleeve it down? Yeah, NO!!
The only bike that should be sleeved is a CR125 down to a 100 - 40 yrs ago.

That being said I would love to find a big bore jug for my KTM 450. I haven’t pulled a holie since I bought it, I loved the power advantage and confidence a big bore gave me
Hate to break it to you but the big bore isn’t what’s holding your starts back
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PFitzG38
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PFitzG38 1/13/2022 3:38pm
1/13/2022 3:38pm
H.E.penyypacker432 wrote:
Hate to break it to you but the big bore isn’t what’s holding your starts back
You should hate to, cause I hate to hear the fact. I see plenty of KTMs get holeshots. Holeshots usually go to whoever expects and wants it most. I lost the confidence when I lost the advantage - I've had a hard time gelling with my steel frame and shift points of a "small bore' 450. After 60+ hours I'm just now starting to figure out how changes like pull rods, bell cranks, diff AER shim stacks/seals and clicker settings effect it. I had my Honda dialed, I could feel a difference with a 1 click or a couple-millimeter change on my fork height.
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mvd61
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mvd61 1/13/2022 8:27pm
1/13/2022 8:27pm
HenryA wrote:
I believe that it's the same kit that is used on the CRF400RX. https://www.redmoto.it/?prodotto-moto=crf-400rx-enduro-2021&lang=en [IMG]https://www.redmoto.it/wp-content/uploads/HONDA_CRF400RX_PRINCIPALE.png[/IMG]
I believe that it's the same kit that is used on the CRF400RX.
https://www.redmoto.it/?prodotto-moto=crf-400rx-enduro-2021&lang=en


FGR01 wrote:
Appears you are right! Here's the kit itself:

https://www.redmotousa.com/product-page/400rx-engine-kit

I’ve ran the 400 and 300 kit on the 250. Both really good. Hoping before the Sumter enduro I’ll get to try the new bike with 300. If you’re off-road check out the RM tanks. I have one on my 21 450rx. It’s 1.5” narrower than stock and I believe two gallon. I cut my own dry break in.
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Timo
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Timo 1/13/2022 8:44pm
1/13/2022 8:44pm
With ignition retard you can really tame a 450, making it very easy to ride. Just hop on your phone and play with, oh wait it's a Honda... If only they had the technology of a Suzuki.
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TheGetFresh 1/13/2022 9:03pm
1/13/2022 9:03pm
What’s the difference in mass of moving engine parts with this kit? One of the advantages of a 350 is the moving parts in the engine are close to the weight of a 250 than a 450, thus the bike is overall more easy to maneuver with less gyro in the engine. Retuning a 450 just makes the power more manageable but the spinning mass in the engine still needs to be overcome.

I’m not suggesting this kit drops enough mass to make a difference, but I am curious.
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Leave Us To
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Leave Us To 1/13/2022 10:41pm
1/13/2022 10:41pm
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
Great point.
backinthesaddleagain 1/14/2022 6:10am
1/14/2022 6:10am
bite_the_curb wrote:
feel like it couldnt be too hard to de-tune a 450 via ecu mapping or using one of those throttle cam things, flywheel weights and gearing

Yeah. Or leave a rag in the air box.
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soggy
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soggy 1/14/2022 7:18am
1/14/2022 7:18am Edited Date/Time 1/14/2022 7:20am
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
THIS TAKE IS SO TIRED. I don’t know who you are manny but I know you are smarter then this. Engine inertia and rotating mass are a real thing that ECU tuning can’t overcome. You could detune a 450 to make power like a 350 but doing so would actually make the bike feel heavier. Giving you none of the benefits of a smaller bore and all the drawbacks of a bigger bore
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cmotodad
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cmotodad 1/14/2022 7:32am
1/14/2022 7:32am
I am curious as to where the drop in weight will happen. A smaller piston but thicker walled cylinder seems like it is a wash.The weight difference in rotating mass is minimal. I'm confused?
soggy
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soggy 1/14/2022 7:38am
1/14/2022 7:38am
cmotodad wrote:
I am curious as to where the drop in weight will happen. A smaller piston but thicker walled cylinder seems like it is a wash.The weight...
I am curious as to where the drop in weight will happen. A smaller piston but thicker walled cylinder seems like it is a wash.The weight difference in rotating mass is minimal. I'm confused?
Smaller piston = less engine inertia
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