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XR and CRF power ratings

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I'm having little luck finding horsepower and torque ratings for the bikes I love. I have seen tests showing XR100 at 7 HP and heard the XR200 is 12 HP. What about the XR250 and 400? A comparison to the CRFs would be interesting, but I just don't have that much money to spend.

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A stock CRF-X puts out 25 hp - with CCC mods closer to 30. CCC mods add top end but don't boost bottom end power on CRF250-X.

An "uncorked" XR400 puts out 30 hp and has more HP and Torque than a CRF250-X until you reach 7k rpm or so (rickramsey.net has a comparison). At 7k rpm an XR400 has twice the torque of a CRF250X (at the same rpm). At that same RPM the xr400 has 12 more horsepower than the crf250x.

The XR motors were designed for off-road. They deliver significant torque at lower RPMs and respectable HP at lower rpms The CRF motors were designed to compete with 2 strokes on a motocross track. They have ultra-short strokes and produce power and torque at much higher rpms. So, it's not just peak power, it's the quality of the power for "trail work" that should be considered.

I plotted the XR250R dyno curve that is referenced above against the CRF-250X (and the XR400) An uncorked XR250R produces more HP than a CRF250X until you reach 7k rpm or so. At 4k rpm an XR250R produces 30% more HP than a CRF250X. It produces 40% more torque at that rpm.

To see hp and dyno curve comparison of CRF250X, XR250 and XR400 look here

- jeff

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why don't u do a comparison of stock vs stock instead of uncorked versus stock?

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Using dyno curves available from a dirtrider test (on-line at www.dirtrider.com).. They have a dyno curve of a 250X with 250R cam and headpipe, baffle and snorkel removed. This changes the story on top, but doesn't change the story down low to mid and actually you give up a little bottom and mid to get gains on top. An uncorked XR250R still puts out more HP than a CRFX up to 7500 rpm - averaging 3 HP from 4000 to 7500 rpm.

Motor-wise - Add a pipe and a carb to an XR250R and it is very competitive to the CRF-X and in tight woods has a distinct advantage.

- jeff

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it's still a bad comparison considering they are using a cam that actually loses low end power. i'm sure the figures are much closer using the stock cam. i couldn't care less about top-end hp. there is a reason why that is called the "closed-course competition" mod. not really meant for increasing trail riding perfermance.

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The same dirtrider test has a dyno curve for a CRF250X with an FMF "Q" pipe installed. Adds a half pony and all of what I said above still holds true - maybe they didn't pull the snorkel, add another 1/2 a pony.

The thing is, you can't take a motor with an extremely short stroke and make it a torque-monster with a different cam... An XR has a much longer stroke than the CRF(X) and that provides it with ample HP and torque down low. An XR still has it's place in this world - too bad honda discontinued it - and I wish they would have produced it with a decent set of front forks. I just went and picked up a new one yesterday - wanted to get a new one before they are all gone. I also have a gasgas ec300 enduro and a gasgas trials bike in the garage.

- jeff

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i understand what u are saying but what r u comparing. the XR250 is not exactly a torque monster compared to the CRF. 2-3 more ft lbs of torque in the lower revs isn't exactly an enormous difference. again, this is with a cam that robs low-end power. don't compare a CRF250 with the XR400. the 400 has an advantage of another 150cc.

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FYI - The torque curve shown is for an "X" model. I took this off of rick ramsey's website - www.rickramsey.net.

The dirtrider dyno curve that I referenced above for the "Q" pipe was with the stock "X" cam.

15 pounds versus 12 pounds of torque (3 pounds difference) is noticable. Add a 280cc kit and bump compression slightly and the difference will be even greater. This can be done at a very low cost (no installation of sleeve required).

The CRF can put out over 30 horsepower on top - this is something that an XR (even pumped to 300cc) is not capable of. This is what the motor was designed for. The XR comes at it from a different direction - longer stroke, different cam timing, lower compression - good bottom end power and torque.

- jeff

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if u got it off rick ramsey's site, it is a comparison of an xr400 vs a crf250r. yes his site is for a 250x but the dyno chart is for a 250r. check ur facts.

again what is the point of saying that a 280kit would make a bigger difference? put a 280 kit on an x and again the differences are minimal. compare apples to apples.

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Oh okay - you are right - I was wrong about rick ramsey's site. But the data with the "Q" muffler on the dirtrider mag site is relevant.

So restating, and correcting, what I have said -> The XR puts out more ponies than a CRF-X at lower RPMs and the comparison of torque is not known. Relative to a CRF250R - an XR250R generates more torque until 7k rpm.

Relative to the 280cc kit. You cannot bore an "X" to 280cc - the stroke is already extremely short relative to the bore. An xr250r has a much longer stroke - you can bore it and yield good HP and torque gains as a result. Because of the extremely short stroke of the CRF-X, you will not see the same relative gains if you go with a larger bore - it's already at the limit (in terms of efficiency). You can increase the stroke on the CRF - but the expense is great.

- jeff

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as far as a big bore kit, there is a 270 kit, but i was just making a point that comparing a big bored xr to a stock crf doesn't make sense. given that they are they start with the same cc, of course u will get better results if u big bore one.

we can go round and round on the dyno's, but lets face it. going out and riding fast, u are gonna go faster on a CRF vs. XR mod for mod. while the crf may give ponies down low, it revs up so quickly that it makes no difference. since it has much better suspension and handling, u will be able to carry higher corner speeds, etc.

what does this all mean for a casual trail rider?

adsolutely nothing. if u are wanting to go exploring and a easy pace, the crf ain't gonna do a damn thing for u. if u like to ride fast, the crf will definitely be a better ride. does it have more maintenance? absolutely. is it worth it? that's for everyone to decide for themselves.

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u are gonna go faster on a CRF vs. XR mod for mod.

Somehow I doubt that, but I could be wrong. The kind of trails I like are really twisty, back and forth, up and down, pretty technical, where you rarely get out of 2nd gear. I can't imagine a CRF-250 going faster in those situations...

It doesn't even come CLOSE to the 400 in power or torque, not at the RPMs I typically ride (and at my pudgy 230lbs... ).

I was considering buying one, but when I saw the curves all graphed out like that, it just seems like it's not suited to the kind of riding I do (which is basically what you said above :) ).

Who knows though? If I ever get a chance to throw a leg over one, maybe those curves won't mean a thing, and I'll say: "Dang, I shoulda bought one of these a long time ago!"

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as far as a big bore kit, there is a 270 kit, but i was just making a point that comparing a big bored xr to a stock crf doesn't make sense. given that they are they start with the same cc, of course u will get better results if u big bore one.

we can go round and round on the dyno's, but lets face it. going out and riding fast, u are gonna go faster on a CRF vs. XR mod for mod. while the crf may give ponies down low, it revs up so quickly that it makes no difference. since it has much better suspension and handling, u will be able to carry higher corner speeds, etc.

...

.

Well, at least I have you past "the denial stage" when it comes to the XR250 putting out more power than your CRF at low to mid rpms. :)

For me, it's a preference thing, I would rather ride a modified XR250R than anything else - I add good front forks, so the suspension part for me - is a non-issue (zoke shiver's off of a cannondale). It is shorter and has a tighter rake and as a result turns tighter than anything else in the woods (especially after you toss the wimpy front fork and triple clamp). I can go faster on this in tight woods than anything else - CRF-X included (I have ridden one).

So I spend $150 on the motor and pump it out to 280cc - That's what you'll spend on one valve for your CRF-X. I'll add a keihin FCR 35mm (have one left over from old bike) and a baffle insert - net result will be a bike that has more HP and torque than your CRF-X. And it will run for 3 years without a re-build and maintenance will be regular oil changes and a valve adjust once a year...

- jeff

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"denial stage"?

at what point did i say that the crf has more low-end power?

i merely pointed out that ur comparisons were flawed.

again, u keep pointing out how once u have heavily modified ur bike, u like it better. great! but fact is most people who get a bike are not gonna get into these type of conversions. really, how many people are gonna find a fork off a cannondale to fit on their xr250's?

i am talking about stock vs stock comparisons or comparisons of mod for mod.

u are absolutely right that it is a preference thing. there is nothing wrong with ur bike, but off the show room floor the crf is a better performing bike. let's not go back to reliability as that issue is very well covered.

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I was considering buying one, but when I saw the curves all graphed out like that, it just seems like it's not suited to the kind of riding I do (which is basically what you said above :) ).

Dyno curves are only part of the equation. Overall gearing determines what speed you'll be travelling when you get into the power curve. Just because the power band occurs at a higher RPM for the X does not mean that it is not well suited to slow, technical rides. In fact, the stock gearing for the X puts the bike in the meat of the power band at very low speeds in 1st gear. In addition, the X power band is quite wide giving you broad latitude in gear selection.

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