Athena CRF450 reduction kit?

usp4u
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usp4u 1/14/2022 7:39am
1/14/2022 7:39am
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
An ECU should not be viewed as a volume knob.

There are several considerations with de-tuning via fueling and timing(which is all you are touching with a ECU). Without additional changes such cam profile, valve events, temperature considerations all you would be doing is dropping the engines volumetric efficiency as you "dial the knob down".

This can result in among other things: detonation, poor throttle response, carbon build up, bearing life concerns, higher EGTs, ect....

Minor tweaks via the ECU is fine...making large changes to an engines character should done as a package to ensure longevity and meeting stated goals without creating new problems.

There is a difference between a guy who works on engines and an Engine Builder.
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Leave Us To
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Leave Us To 1/15/2022 2:51pm
1/15/2022 2:51pm
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
usp4u wrote:
An ECU should not be viewed as a volume knob. There are several considerations with de-tuning via fueling and timing(which is all you are touching with...
An ECU should not be viewed as a volume knob.

There are several considerations with de-tuning via fueling and timing(which is all you are touching with a ECU). Without additional changes such cam profile, valve events, temperature considerations all you would be doing is dropping the engines volumetric efficiency as you "dial the knob down".

This can result in among other things: detonation, poor throttle response, carbon build up, bearing life concerns, higher EGTs, ect....

Minor tweaks via the ECU is fine...making large changes to an engines character should done as a package to ensure longevity and meeting stated goals without creating new problems.

There is a difference between a guy who works on engines and an Engine Builder.
I know from reading his posts for years Team Green is aware an ECU is not a volume knob.. Before I would spend the dollars for this kit which will only provide minimal inertia reduction, I would dial back the power as Team Green suggested.
2
usp4u
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usp4u 1/21/2022 11:14am
1/21/2022 11:14am
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
usp4u wrote:
An ECU should not be viewed as a volume knob. There are several considerations with de-tuning via fueling and timing(which is all you are touching with...
An ECU should not be viewed as a volume knob.

There are several considerations with de-tuning via fueling and timing(which is all you are touching with a ECU). Without additional changes such cam profile, valve events, temperature considerations all you would be doing is dropping the engines volumetric efficiency as you "dial the knob down".

This can result in among other things: detonation, poor throttle response, carbon build up, bearing life concerns, higher EGTs, ect....

Minor tweaks via the ECU is fine...making large changes to an engines character should done as a package to ensure longevity and meeting stated goals without creating new problems.

There is a difference between a guy who works on engines and an Engine Builder.
Leave Us To wrote:
I know from reading his posts for years Team Green is aware an ECU is not a volume knob.. Before I would spend the dollars for...
I know from reading his posts for years Team Green is aware an ECU is not a volume knob.. Before I would spend the dollars for this kit which will only provide minimal inertia reduction, I would dial back the power as Team Green suggested.
I dont understand you guys are expecting a change in "inertia" with a slightly smaller bore.

Reciprocating mass has much less to do with it than rotating mass. Shorten the stroke, lighten the crank, then worry about the bore. I would much prefer a short stroke/ large bore combo to prevent valve shrouding.
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TeamGreen
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TeamGreen 1/21/2022 2:25pm
1/21/2022 2:25pm
usp4u wrote:
An ECU should not be viewed as a volume knob. There are several considerations with de-tuning via fueling and timing(which is all you are touching with...
An ECU should not be viewed as a volume knob.

There are several considerations with de-tuning via fueling and timing(which is all you are touching with a ECU). Without additional changes such cam profile, valve events, temperature considerations all you would be doing is dropping the engines volumetric efficiency as you "dial the knob down".

This can result in among other things: detonation, poor throttle response, carbon build up, bearing life concerns, higher EGTs, ect....

Minor tweaks via the ECU is fine...making large changes to an engines character should done as a package to ensure longevity and meeting stated goals without creating new problems.

There is a difference between a guy who works on engines and an Engine Builder.
Leave Us To wrote:
I know from reading his posts for years Team Green is aware an ECU is not a volume knob.. Before I would spend the dollars for...
I know from reading his posts for years Team Green is aware an ECU is not a volume knob.. Before I would spend the dollars for this kit which will only provide minimal inertia reduction, I would dial back the power as Team Green suggested.
usp4u wrote:
I dont understand you guys are expecting a change in "inertia" with a slightly smaller bore. Reciprocating mass has much less to do with it than...
I dont understand you guys are expecting a change in "inertia" with a slightly smaller bore.

Reciprocating mass has much less to do with it than rotating mass. Shorten the stroke, lighten the crank, then worry about the bore. I would much prefer a short stroke/ large bore combo to prevent valve shrouding.
I get the feeling you might be someone who tried/tested/ridden some of these "optional engines".

For what's being discussed here, I'd be much more inclined to try the 300 kit on the 250.

There's so much "torque & traction" along with power moderation available in a good ECU these days. As someone who's ridden all the Hondas, the new 450X engine is a Do-ALL engine with awesome power characteristics. It's just stuck in a HEAVY package. I know. I've got one. But, using that type of ECU base setting as a starting point in the R/RX would be a good way to go.

The 413cc kit is cool for the guys that want to fiddle with stuff; but, as I said in the onset...a good ECU tune will accomplish comparable results. Folks like Jamie Ellis have proven this to me.

Don't think I ever called an engine computer with 3D mapping capabilities a "Volume Knob"...? Grinning

No worries. Everyone's got opinions. I was just offering mine.
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Phillip_Lamb
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Phillip_Lamb 1/21/2022 2:42pm
1/21/2022 2:42pm
i remember around 2007-2008? someone made a 400 kit for the Yz450 and Drd tested it. but i could never find it\\

i imagine the benefits are to get more of a 350 feel, less inertia feel from the bike and a little less torque. this is why i prefer a 350, it has the lighter feel weigh wise and inertia feel of a 250 but enough grunt to get over pesky jumps.

on a 450 i always feel like i have to fight to keep it in check
CharlieJ125 1/21/2022 3:41pm
1/21/2022 3:41pm
Classic Vital thread here, the question was if anyone had any additional info/experience with the kit. Follow that up with speculation and advice to big bore and use an ecu Laughing
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CarlinoJoeVideo
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CarlinoJoeVideo 1/22/2022 7:24am
1/22/2022 7:24am
I’d be really interested in hearing a a Honda 413 bike test. Sounds like it could be a fun bike?
Berni
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Berni 1/22/2022 8:21am
1/22/2022 8:21am
An enduro CRF is sold in Europe with this kit through Redmoto in Italy. If you look for some CRF400 RX bike test, maybe it will help with your question
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mark_swart
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mark_swart 1/22/2022 8:27am
1/22/2022 8:27am
TeamGreen wrote:
Uh…yeah…

Or, you could just dial down the power via your ECU, right?
soggy wrote:
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...
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
Amen!! What makes a 450 hard to ride isn't just the acceleration, it's the mass in motion. For me the most nerve racking thing about 450s is actually corner entry and getting them into the turns where I want. And of course when they get a bit out of line you have less chance of getting them back.

Unfortunately, I don't think changing just the piston and bore would have that much impact on all of that mass, but I could be wrong.
bite_the_curb 1/22/2022 9:08am
1/22/2022 9:08am
people have been putting flywheel weights on bikes forever, along with taller gearing.

all of those would be alot cheaper than this
MBR
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MBR 1/22/2022 9:24am
1/22/2022 9:24am Edited Date/Time 1/22/2022 9:28am
I have tested the Honda Redmoto 400 a few times and the difference to CRF450R is much bigger than you can achieve with ECU (I have plenty of experience on that also). I really liked the 400 especially on hard pack and slippery conditions. The engine picks up rpm much faster, has less inertia and engine braking and is easier to control. I could get on the gas much earlier and my corner speed was improved. The lighter feeling engine makes the whole bike feel much lighter and easier to ride. I’m actually considering installing the kit also to my motocross bike this season.
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Greenbush
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Greenbush 1/24/2023 7:35pm
1/24/2023 7:35pm
MBR wrote:
I have tested the Honda Redmoto 400 a few times and the difference to CRF450R is much bigger than you can achieve with ECU (I have...
I have tested the Honda Redmoto 400 a few times and the difference to CRF450R is much bigger than you can achieve with ECU (I have plenty of experience on that also). I really liked the 400 especially on hard pack and slippery conditions. The engine picks up rpm much faster, has less inertia and engine braking and is easier to control. I could get on the gas much earlier and my corner speed was improved. The lighter feeling engine makes the whole bike feel much lighter and easier to ride. I’m actually considering installing the kit also to my motocross bike this season.

I know this is a year later but I’m wondering if you went ahead and did the 400 kit for moto and what are your thoughts? Thinking of maybe going that route but not much info out there that is motocross specific. Mostly just off-road.

 Thanks 

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