Any articles on the 05 CR models?

[Studboy]

OK OK, so you have more peak horsepower over a narrow RPM range, unless you are real good at keeping the RPMs right there, the bike with more power over all is going to be faster.

 

[Rcannon]

I wonder if it is more complicated than simply...POWER!!!

Many times on the track you see things that should not be possible. The 125 passing the 250 on the straights. The guy on the XR 250 keeping up with the YZ's and KX's.

I watched studboy ride the xr 250. The bikes with double the power were never able to pull away from him.

Honestly I would look at the dyno chart on the 2002 cr 250 and laugh. I know what the numbers say......close to 47 hp. I also compared it to shifters crf 450. The crf was fast and powerful and would show about 47 hp. Yet, in real life riding the crf would run away from the 250.

If I remember anything from physics (which is doubtful) it was that troque was just as important as horsepower. When we open the throttle on a powerful truck or motorcycle, is'nt torque what we feel???

 

[steve125]

It still is not an accurate comparison unless you do a pre modified baseline....

You just can't pull a dyno chart out of a hat to prove that another bike is "more powerful" unless you do them all on the same day and same dyno...

And still, different dyno's read differently so this is why it is important to do them all on the same dyno...

All im saying here is that dyno chart that Marcus provided shows that bikes true HP numbers for the state of tune it was in. Sorry you don't like the numbers, but the SAE software is there so the runs can be compared on different days and temps.

His chart is good and since there has been no other comparasion made on that dyno to the one he's shown I don't know what the beef really is with it?

Is the number too low in your mind?? if so don't worry it only applies to that dyno anyway.

 

[pace]

All im saying here is that dyno chart that Marcus provided shows that bikes true HP numbers for the state of tune it was in. Sorry you don't like the numbers, but the SAE software is there so the runs can be compared on different days and temps.

His chart is good and since there has been no other comparasion made on that dyno to the one he's shown I don't know what the beef really is with it?

Is the number too low in your mind?? if so don't worry it only applies to that dyno anyway.

In the car world, we see different dynamometers throw out vastly different SAE corrected horsepower numbers. Horsepower is a derived value (from torque), and different dynos with differing mechanisms will produce different numbers. I cannot imagine motorcycle dynos are any different in this regard. SAE correction attempts to normalize for barometric conditions, but different equipment will still derive different results. Even dynos of the same type can produce different numbers due to calibration variances.

That is the fact that John is alluding to, I believe. Any engine builder knows that comparison between different dyno charts are largely meaningless unless it's the same dyno on the same day.

-pace

 

[marcusgunby]

Sorry but that is fred bollys world gp winning 2002 bike-i can put up a husky gp 250 but it would embarrase the honda engine so bad its not funny, i can put it in any conversion factor you want and its still the same chart give or take a hp.

Good 250 is 50rwhp-any more is dreaming, any less is crap.

still not seen the 54hp one??

kart engines etc are pointless as they cant be used in mx-i want to see mx engine dynos. :moon:

 

[marcusgunby]

And becuse i couldnt resist heres the comparison, the husky cr engine was later tamed down to around 50hp for more rideable engine and more bottom end.Doesnt say much for the honda cr LOL.

 

[steve125]

That is the fact that John is alluding to, I believe. Any engine builder knows that comparison between different dyno charts are largely meaningless unless it's the same dyno on the same day.

-pace

What is the difference between 1 day and the next on the same dyno?? Temp and humidity that can influence the results right? The SAE correction factors that out, so runs can be compared on different days. I've done it many times when repeating runs on different days and my numbers have not changed when returning to a previous setting. Now with no correction??? My numbers are all over the place.

 

[marcusgunby]

You can get small variations day to day even on something like how dry the chain is(nearlry 1hp more on a oiled chain BTW) but a good dyno operator looks to mininalise these changes to provide usefull real world data.KP has done 10000s of runs and doesnt use the dyno to try to make one engine look good or bad-just wants to see whats wrong and how to fix it, i suspect honda knew they had a problem and thats how the bike ended up on the dyno, everyone assumes the factories know how to build fast bikes but look at the cr125s of the last 5 years.

 

[pace]

What is the difference between 1 day and the next on the same dyno?? Temp and humidity that can influence the results right? The SAE correction factors that out, so runs can be compared on different days. I've done it many times when repeating runs on different days and my numbers have not changed when returning to a previous setting. Now with no correction??? My numbers are all over the place.

I don't think anyone is disputing that a particular dyno will produce the same SAE result on Wednesday as on Monday of the same week. The 'same dyno, same day' comes from observations that dynos do get out of calibration, that tires do wear, that motors heatsoak under certain conditions, etc. And the main point of contention is that different dynos will produce different results, SAE or not. Furthermore, different engines react differently to differing ambient conditions. SAE is good for a 'ballpark' figure, but if you think it's universally infallible then you might want to read up on what happens when we SAE correct high-altitude output, particularly from turbocharged motors (just one example).

There are bunches of good articles on the web that talk about the problems with trying to compare charts from different dynos - the different methods in which horsepower is derived, the variables that SAE does not take into consideration.

You can find the same dyno chart vs. dyno chart bickering on every auto forum out there, and many of these arguments arise from ignorance in the fundamentals of how horsepower is 'measured'. Now it personally makes no difference to me whether the CR makes 0.5 HP more than the YZ, or vice-versa. Does your bike feel good at the track... are you pulling on other riders...? My riding partner pilots an '00 KX250, so he's my main target. He pulls me on the bottom, and then I walk him on top. Overall my bike is faster. That's really all I care about, not what my 'SAE' output measures at on dyno XYZ.

-pace

 

[Someone]

Yeah it was a good read....He left Honda because they wouldn't sign him to the deal he wanted..

And, he sure didn't have any problem with his starts in 02' when he had the perfect season...Even against a whole laod of 4 strokes in 03' he got good starts.

Dirtrider quote:
Honda won't address Camichael's criticisms of the CR250R...

Dirtrider quote:
He (RC) no longer believed his works Honda CR250R was as competitive as some of the other bikes out there, and concluded he would have to race the CRF450R indoors.

RC Quote:
I thought the CRF was the best bike Honda had to offer, The company's two-stroke wasn't at the top of its game. Yamaha had advanced so much, and the CR didn't have any low-end power or torque. So I had to go to a bike that could allow me to perform and win.

 

[marcusgunby]

I think the issue the thread was pointing to was the cr has a poor engine for mx, no modern cr250 engine is as good as the ktm, rm , yz engine on the same day on the same dyno(apart from peak hp)i was showing this to be true even on a factory honda bikes- if you want a good mx engine avoid the modern cr250s.

Someone said there was a 54hp cr250 and i was just curious to see the dyno-too many people talk about hp and never show the proof, i dont mind if it is a kart engine as i will be able to see the lack of bottom end power anyway.

 

[steve125]

I don't think anyone is disputing that a particular dyno will produce the same SAE result on Wednesday as on Monday of the same week. The 'same dyno, same day' comes from observations that dynos do get out of calibration, that tires do wear, that motors heatsoak under certain conditions, etc. And the main point of contention is that different dynos will produce different results, SAE or not. Furthermore, different engines react differently to differing ambient conditions. SAE is good for a 'ballpark' figure, but if you think it's universally infallible then you might want to read up on what happens when we SAE correct high-altitude output, particularly from turbocharged motors (just one example).

There are bunches of good articles on the web that talk about the problems with trying to compare charts from different dynos - the different methods in which horsepower is derived, the variables that SAE does not take into consideration.

You can find the same dyno chart vs. dyno chart bickering on every auto forum out there, and many of these arguments arise from ignorance in the fundamentals of how horsepower is 'measured'. Now it personally makes no difference to me whether the CR makes 0.5 HP more than the YZ, or vice-versa. Does your bike feel good at the track... are you pulling on other riders...? My riding partner pilots an '00 KX250, so he's my main target. He pulls me on the bottom, and then I walk him on top. Overall my bike is faster. That's really all I care about, not what my 'SAE' output measures at on dyno XYZ.

-pace

Luckily the dynos don't have wings. Im sure large altitude changes would really mess with the correction factor. But in the real world, the charts are comparable. In the "ball park" is fine. One thing for sure without SAE, there would be no comparing at all but on the day of the dyno run. And even then temps and humidity can change. SAE helps maintain a balance.

 

[marcusgunby]

I forgot to say on bottom end from a cr engine, KP did the ex world enduro champion(Eddy edmondons) cr250 this year, he lowered the cylinder , used different pistons and lots of other tuning and still couldnt get the bottom end power better than a yz/rm it had about 44hp which was plenty but didnt have a nice straight line like you see on the husky cr, the honda engine is actually borrowed from a road bike in japan i believe-they did this to save in R+D as the 450 was on its way, you can see why its not the best mx engine-it was never designed to be.

 

[Rcannon]

What does SAE stand for exactly?

 

[pace]

The charts between different dynos are comparable if you're unconcerend about 5% (whatever) discrepancies. You really should inform yourself before making assertions that are simply not borne out in reality. As I said, google will yield you with a TON of information on why quoting/comparing different dyno charts should be accompanied with a caveat.

In the 'real world' there are dirtbike owners in the Netherlands, in midwest America, and in the Rocky Mountains, who operate under vastly different conditions. John's argument was that different dynamometers in different locations may produce different dyno results, so let's stay on topic if you want to debate that point. I already stated, very clearly, that we're not contending the same dyno producing the same result on two consecutive days.

The supposed 50-something horsepower 250 reminds me of these 40 horsepower 125s that pop up from time to time. ;)

 

[pace]

What does SAE stand for exactly?

What does HP stand for exactly?
:bang:

 

[pace]

I forgot to say on bottom end from a cr engine, KP did the ex world enduro champion(Eddy edmondons) cr250 this year, he lowered the cylinder , used different pistons and lots of other tuning and still couldnt get the bottom end power better than a yz/rm it had about 44hp which was plenty but didnt have a nice straight line like you see on the husky cr, the honda engine is actually borrowed from a road bike in japan i believe-they did this to save in R+D as the 450 was on its way, you can see why its not the best mx engine-it was never designed to be.

Building a CR for bottom-end seems akin to porting a pre-05 KX for overrev. There are platforms better suited to provide that kind of delivery.

Ahh.. I see hoardes of DRN readers ditching their Hondas and running out to pick up that hot Husky. :eek:

-pace

 

[marcusgunby]

LOL pace , most of the riders of those huskys wanted a honda cr simply due to the fact even a top go rider(paul cooper got 6th on it i think) couldnt hang on well after 30 minutes, when cark nunn rode it he had a switch on the bars to tame it down for the last half a race-what a waster:(

 

[steve125]

The charts between different dynos are comparable if you're unconcerend about 5% (whatever) discrepancies. You really should inform yourself before making assertions that are simply not borne out in reality. As I said, google will yield you with a TON of information on why quoting/comparing different dyno charts should be accompanied with a caveat.

In the 'real world' there are dirtbike owners in the Netherlands, in midwest America, and in the Rocky Mountains, who operate under vastly different conditions. John's argument was that different dynamometers in different locations may produce different dyno results, so let's stay on topic if you want to debate that point. I already stated, very clearly, that we're not contending the same dyno producing the same result on two consecutive days.

The supposed 50-something horsepower 250 reminds me of these 40 horsepower 125s that pop up from time to time. ;)

I never once was implying 2 different dynos should jive. Only that SAE correction is in the software for a reason. Thats it!!!

 

[Rcannon]

Pace, you dont know what SAE stands for.

It was ok to say .."I dont know."

Can you give the definition of HP without looking it up?

I get a kick out of forum readers and people in general. They will fight to the death over their choices. Even when it can be proven over an over that their choices were bad.

The Honda uses a poor engine design. According to Eric Gorr's new book Mike Larocco did not even use the new Honda CR 250 engine until 2004!

If more proof is needed scan a local Honda dealership. Make an offer on their new 2003 or 2004 CR 250's. Be careful, they might sell you one.

Yet you appear hell bent on making me look foolish for asking a question about SAE.

 

[pace]

I get a kick out of Internet warriors who try to move an argument away from it's original intent in order to support their case. The point that I responded to was regarding comparison of dyno sheets, not the merits of Honda engine design or sales figures (and by the way, you might want to check your facts on the most sold 250 2-stroke of 2003/2004).

I've spent many hours with my vehicle and others on the local dynamometer, so I have a basic understanding of how the SAE correction factors apply. The point made was that each dynamometer figures horsepower differently, so even if you apply the same SAE calculation to dyno X you're going to end up with a different result than dyno Z. That's all.

I'm not hell bent on making you look foolish. On the contrary, it seemed like you who is trying to catch me out on basic terminology. I'm an engineer and an auto enthusiast, and so am very well aware of what SAE stands for. If your question on SAE was genuine, I truly apologize. I read it as you calling me out.

Some folks here seem to be 'hell bent' on engaging some kind of religious brand war. My CBR and CR were my first Hondas - prior to that I owned only YZ dirtbikes, so you're picking a fight with the wrong guy here. I'm not much interested in those flamewars, but if I see such obviously misleading statements that dyno sheets are universally comparable then I'm gonna call it.

I guess this thread has been pretty well hijacked.

-pace

 

[Rcannon]

Sorry for making it sound like a calling out. I did not mean anything of the sort. The sae was genuine.

I would love to know about 100 times as much as I do about all of this. The SAE makes me wonder. I know what the initials stand for. But what does it really mean????? It sounds odd that so much time and effort over the years was spent trying to make sence out of how much coal a horse could lift?

Has a better measurement not been devised? Some sort of unit that includes both horsepower and torque?

As a basic consumer a person see's these things. The Dodge diesel advertisements come to mind. They will boast about 600LB/ft of TORQUE!!!!! But the horsepower measures at 180.

 

[steve125]

but if I see such obviously misleading statements that dyno sheets are universally comparable then I'm gonna call it.



-pace

Who said that in this thread???

 

[pace]

As a basic consumer a person see's these things. The Dodge diesel advertisements come to mind. They will boast about 600LB/ft of TORQUE!!!!! But the horsepower measures at 180.

The relationship between torque and horsepower is certainly somewhat misunderstood by the general consumer. Especially when we say things like 'it has great torque' to describe a motor that has lots of low end grunt.

The twisting force at the crankshaft of your motor, or your rear wheel, is torque. Horsepower is just a measure of the rate at which your motor can work (ie. it factors in time), and thus the power of your motor is a function of torque and RPMs.

IIRC, horsepower = (torque [lbs-ft] * RPMS) / 5250

..I don't remember where the constant comes from, but I do know that a consequence of this is that ALL dyno charts should show torque and horsepower crossing at 5,250 RPMs.

And that is about the extent of my knowledge on the subject. Maybe someone else can shed light, on the origin of the 5250 (?) constant.

What you can conclude from output specs that show a motor producing massive torque but not much horsepower, is that it's torque peak occurs at very low RPMs, and then either falls away significantly with increasing RPMs or else is 'artificially' constrained by a low RPM limit. This is typical of big diesels.

-pace

 

[vetcr47]

what a load of crap....can you say swedetech....they tune moto cr 125 engines that are pushing 45+hp everyday....the sgm 125 and pavesi's are 40+ hp out of the box.....there is alot of potential there....I'm told the fuel is worth 2.+ hp at least.....and the vp stuff bubba uses @ $34.00 a gallon is even better than the mr2 / mrx01 that the public gets....do they need rebuilt bottom ends every 8 hours - yes....but they are verrrry tunable, prog ignitions, ect...talk to the guys at jm racing and you will see the results of real cr-125 development...