Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: JohnN on December 10, 2009, 04:18:21 PM
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(http://i100.photobucket.com/albums/m26/YZ_John/CRF450_Dyno_Chart.png)
When MXA was dynoing the 2010 Honda CRF450, all the gang kept asking how the bike was doing on the dyno. Eventually, getting tired o the endless questions about what the CRF450 curve looked like, Jody said, "It looks the he side view of the Sprinter van."
And It does. For every backyard expert who clams that the CRF450 has unbelievable top-end power, this dyno chart should be visual proof that the CRF450 produces a solid climb in power from 5000 rpm to 8200 rpm (and after that the CRF runs flat to 11,20 rpm). Once it reaches 50.90 horsepower, it flattens out and does not make any additional power (although it does rev until it hits the rev limiter).
It is a low to mid engine-'nuff said.
Interesting how far off seat of the pants impressions can be from reality. But since a bike is not raced on a dyno, what method would you trust to determine the best race bike on a closed course?
Personally I would go for a combination of the best feeling bike with the best laps times.
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HAHAHA that is so frikkin funny :D
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I'm not surprised that the Honda only makes about 51 HP. That's what a 250 2T produces. I don't want to get into it here, but there are several reasons why that extra 200cc's makes a big difference...and it's NOT torque.
That said, a dyno is a tool. You can learn a lot from it. But, it takes out factors because it does not test DYNAMICALLY. It is a static test, much like a flow bench. It does not test dynamically.
If correctly geared (secondary and PRIMARY), and if the rider understands the power curve (which I doubt many do) and rides it accordingly, it will be as fast as 51 hp at 8000 rpms can be. If, someone comes along, builds the same HP, but does it at 10,000 rpm and it is geared accordingly and ridden with the same consideration as above, the one the rev's higher will be faster than the one that only rev's to 8000 rpm. We are talking 4 strokes here. The same principles apply, but 2 strokes have a power cycle twice as many times as does a 4T.
Lap times are important, but...that's why I hate shootouts. Guys jump on a bike, don't adjust the controls and don't spend enough time to get to know the bike. If the bike is very different from what they consider to be the "norm", the bike gets hammered. Ask KTM. They have been trying to sneak up on Asian handling for years.........
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When you're racing lap times are everything.
And I'd love a curve like that billiard table one at the top.50 for a 4000 RPM band?Take your pick of what gear to use.Some tracks that would give me a three gear choice with an occasional clutch burp.Pull it wide open anywhere above 8K and 50 in your hand.Damn.
How many of you guys race?
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That's why I said "lap times are important but........". Understanding that particular power curve requires different things from riders.
Sooooo, if a guy jumps off of bike "A" to bike "B" with the above power curve and goes SLOWER on bike "B" does that mean bike "B" is a pooch?
Like I said.........LAP TIMES ARE IMPORTANT.............BUT.........consider the source.
Yes I race, bikes not so much any more.
Retired drag racer/engine builder.
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I race. Coming back from ACL-surgery exactly one year and one week ago, spending most of this year in rehab and getting back on the bike.
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Oh yeah!!!!!!!! http://motocross.transworld.net/videos/texas-grudge-match/ (http://motocross.transworld.net/videos/texas-grudge-match/)