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CRF450 Power Decrease?

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Hello, I know that this may sound a little akward, but I would like to ask if there is any way to decrease the power of a CRF450.

But first let me explain the situation I'm into.

I currently have a 2-stroke Husky WR250 which I mostly use for enduro rides and a little for motocross.

As the last 2 years I was out of the fields I'm currently in a bad shape(not that I ever was in a advanced level). So, my 2-stroke 250 tires me up sometimes, because it has lot of power, but sometimes I definitely need it's power, which a 125 would not give me(for example in big uphills etc.)

I'm 180lbs and I would like the bike to be as light as possible, so I decided to go for a motocross bike this time and not an enduro one. As I mostly like enduro I would prefer a 4-stroke bike.

Now, what's the problem I have...

I know that a CRF450 has plenty of power, even more than a 2stroke CR250, so I think that it may not be wise to buy a bike like that and would be better to go for a CRF250.

The problem is that I want a used bike and I cannot find a good CRF250 here in Greece(or even a YZ250F) but I have found some very good 450s.

So the thing I'm asking is, if there is any proper and easy way to decrease the power of a 450 to suit me, and maybe later in the future be able to use it in case I need it. Because I'm sure that a normal 450 will be too powerfull for an almost novice rider as I am and will tire me a lot rather than helping me improve.

I would be grateful if you can give me any advice or suggestions.

Thanks in advance.

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The easiest way to de-tune a CRF450 across the entire power band and have the ability tune it back to where you started is with an exhuast that will let you intsall and remove a quite core.

FMF and pro-moto billet are two examples of exhuast systems that have inserts to quite a motorcycle. These inserts are a cheap and effective way to de-tune your bike.

Kevin

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I have heard some off road riders looking for a mellower power delivery have put a FMF Q on the bike. It restricts the flow a little bit and there for mellows the bike a bit.

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The easiest way to de-tune a CRF450 across the entire power band and have the ability tune it back to where you started is with an exhuast that will let you intsall and remove a quite core.

FMF and pro-moto billet are two examples of exhuast systems that have inserts to quite a motorcycle. These inserts are a cheap and effective way to de-tune your bike.

Kevin

Putting in a quite core will not do much to your power! I could not tell the difference, a fly wheel is your best option if you feel the power is too much. Crf450 05 was my first bike and I learned with a flywheel, and then sold it.

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Utah,

4 strokes work off of pretty simple physics. The more air and gas you effectively move through the motor the more power you will have. Slow/restrict the air movement on either end (intake /exhuast) and the less power you will have.

Weighted fly wheels don't make less power on a 4 stroke. They just move the power to the lower end by making the bike rev slower. Once you get going you will have the same power.

Kevin

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wouldn't it be easier and cheaper to change the sprockets? add a few teeth to the rear. even 1 to the front. i know there would be no change in "power" but wouldn't the bike be a tad bit more controllable. making it easier to ride, especially since this rider is more into enduro? i know my crf450 was my first bike in over 15 years, and coming off an 83 xr200, i've transitioned well. personally, i think the 450 would be the way to go, you'll learn to appreciate the power.

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Hello, I know that this may sound a little akward, but I would like to ask if there is any way to decrease the power of a CRF450.

But first let me explain the situation I'm into.

I currently have a 2-stroke Husky WR250 which I mostly use for enduro rides and a little for motocross.

As the last 2 years I was out of the fields I'm currently in a bad shape(not that I ever was in a advanced level). So, my 2-stroke 250 tires me up sometimes, because it has lot of power, but sometimes I definitely need it's power, which a 125 would not give me(for example in big uphills etc.)

I'm 180lbs and I would like the bike to be as light as possible, so I decided to go for a motocross bike this time and not an enduro one. As I mostly like enduro I would prefer a 4-stroke bike.

Now, what's the problem I have...

I know that a CRF450 has plenty of power, even more than a 2stroke CR250, so I think that it may not be wise to buy a bike like that and would be better to go for a CRF250.

The problem is that I want a used bike and I cannot find a good CRF250 here in Greece(or even a YZ250F) but I have found some very good 450s.

So the thing I'm asking is, if there is any proper and easy way to decrease the power of a 450 to suit me, and maybe later in the future be able to use it in case I need it. Because I'm sure that a normal 450 will be too powerfull for an almost novice rider as I am and will tire me a lot rather than helping me improve.

I would be grateful if you can give me any advice or suggestions.

Thanks in advance.

get the 450 and ride it,i bet you love the power delivery- power is spread out across the band instead of hitting suddenly like the 250

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Yeah he is right, the power is sweet, smooth. If you want less power, get a CRF250, they are sweet, and rev to like 12K RPM. BUt I own a CRF 450, and it is sweet.

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Depending on what year CRF 450 your are looking into buying you can replace the flywheel to a heavier one thus mellowing out the powerband. If you are looking at a 02 or 03 they already have a heavy flywheel. If you are looking at a 04 or 05 you can use one off of a 02 or 03 to tame it down since they are a few ounces heavier. Since Honda went with the lighter flywheels in 04 and 05 to give the bikes more snap on the bottom end. The diffirence is 2 or 3 ounces as I remember it. Check with a Honda dealer for exact specs as far as the weights of the flywheel goes. Then there are always different exhaust systems, and sprocket combos you can go with as well to tame down the bike a little. Good luck.

Tony

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Utah,

4 strokes work off of pretty simple physics. The more air and gas you effectively move through the motor the more power you will have. Slow/restrict the air movement on either end (intake /exhuast) and the less power you will have.

Kevin

true, but it is minimal, so it's just not going to help him much.

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For about $2 you can take the top of the carb off and drill it for a bolt and jam nut so you can limit the slide travel. Want a 25 hp 450? set it so you can only get about 1/2 throttle. Its sooo cheap to take HP out. Way more expensive to add more.

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Thank you very much guys for your replies.

To be honest I didn't have the chance to try an off-road 4-stroke. But I think that a 450 will have much more power than I need.

So are you are telling me that it may be easier to ride a 450 than a 250 2-stroke? If yes, then maybe I'll go for it.

The only thing I'm afraid of, is if a 450 is too powerfull and become dangerous to my hands.

The CRF450 I found is a '04 one.

I understand that a different exhaust may help but I don't think that it will make a big difference. A 3-5 HP loss won't make a difference.

About the flywheel you are telling, maybe it is a good solution, but I also find very good the idea of modifying the carb. Don't that be the best solution?

I don't know CRF's carb but I read that it is a Keihin FCR. In my KTM Duke II which I have installed a Keihin FCR41-MX there was a stopper that did what bd450 mentioned. It prevented the slide from opening more than 50% and I just replaced it with a one that opens 100%. No need for drills or damaging the carb, I just replaced the stopper screw with another one. Do you think that something like that would help and be a better solution than replacing the flywheel?

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A fourstroke 450 is so much easier to ride than a two stroke 250 its hard to even describe.

Even with the ultimate power being greater, its completely measured. A thumper isnt going to jump out from beneath you unless you open the throttle and tell it to.

As far as taming the thumper, Id have you ride it first. You'll end up reallizing how nice it is and just riding it the way it is... :)

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More on flywheels:

QUESTION SEVEN: DOES A HEAVY FLYWHEEL COST HORSEPOWER?

NO. Heavy flywheels do not cost horsepower. They only change the way the power is transferred to the ground.

QUESTION EIGHT: CAN A HEAVY FLYWHEEL MAKE A BIKE FASTER?

Yes. But only if the engine characteristics are too snappy, powerful or explosive for the rider’s style or track’s terrain. A bike with an engine that's too explosive will accelerate quicker with a heavier flywheel weight.

Why? Because the weight smoothes and broadens the transfer of power to the ground. The power is delivered more consistently and in more of a conservative manner. The bike is more hooked up off the line and less volatile on the course.

If you want to get more on the truth about flywheels(heavier) go to

http://www.motocrossactionmag.com/ME2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=7CAB46032CC84FECABD88FEB2D40E11D

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In my KTM Duke II which I have installed a Keihin FCR41-MX there was a stopper that did what bd450 mentioned. It prevented the slide from opening more than 50% and I just replaced it with a one that opens 100%.?

A KTM Duke II??

Isnt that Like a 640 or 650 with somwhere around 55-60 HP???

If soo, why do you think youll need to slow down the ol' 450? Just buy one, and ride it within you abbility. Remember, you have control over how fast YOU go.Its all in the wrists!!

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