Favorite Bike

[offroader]

What people forget in the horsepower "Debate" is TORQUE.
That determines acceleration. Not horsepower.
A 500 smoker has way more torque then a 250 regardless of what the quoted "horsepower" is.
The modern 250's have about 29ft/lbs of torque. Just a couple below a 450F.
Not sure what an old CR500 has but, it would be a hell of alot more.
I wish manufactors published torque figure instead of horsepower figures.

I agree with that and say it often.Just ask John. A dyno is a great tool for getting an idea of what some of the difference is when making changes pipes,porting etc. but it certainly is not the be all to end all.If you have two cylinders and one makes 50hp on the dyno and one makes 55hp on the dyno but the rider is more comfortable and turns better lap times on the bike with 50 hp should he still use the cylinder that produces 55hp on the dyno?

[Coop]

D'oh

Hey,wait.What if I was to run the old YZ on Jetz's Maico Dyno?

Well if it says Maico, you know it's superior to anything else and will make your bike faster just from being in its presence...

[TMKIWI]

D'oh

Hey,wait.What if I was to run the old YZ on Jetz's Maico Dyno?

Well if it says Maico, you know it's superior to anything else and will make your bike faster just from being in its presence...

 

[JETZcorp]

I was reading a really, really, REALLY old dirt bike test the other day, and they happened to include a quarter-mile time, as well as a 0-60 time in that.  I think that's just about the best way to figure out how the bikes do engine-wise.  Dynos are great for finding what modifications do to a bike, but unless ALL the variables are held constant in ALL situations, they fall short for comparative data.  Seat-of-the-pants is perfect for deciding what you're comfortable with, but it can be deceptive in terms of pure winning.  For example, in the first issue of Dirt Bike, they tested three European 250s, and Super Hunky found that one of them felt much slower than the others, but still posted lap times three to five seconds a lap faster.  I'm going to leave it open to the imagination which bike that was in this CZ - Maico - Husky test.

But, when you want to win, the clock is ultimately the one who decides the winner, so I think it should be the tool we use to figure bikes out.  Get lap times, obviously, but instead of talking about which bike felt the fastest or pulled the dyno off the floor, have someone on the Magazine test crew who is the master of drag racing dirt bikes, and tell him to post some numbers on all the bikes.  That would weed out the bikes that post big dyno numbers (like that one year CR250) or the holy-shit-this-feels-faster-than-it-is bikes, and tell the world what can really lay it down, and what can't.

[ford832]

Nope,wayyyyyy too many variables there
Dynos are actually reasonably accurate given temp/pressure/dyno type/operator differences.Still,a couple HP difference between when talking 30,40 hp isn't a huge deal.On a 5 hp engine it would be for sure.Most of the Dyno debate comes from people who don't want to believe their bike makes as little hp as it does-ahem
In the superbike series up here,all the top finishers must have their bikes dyno'd on the track dyno to confirm the hp figures aren't over the class limit.
For a fee,anyone there can have their bike run on the same dyno.While the racers/tuners don't debate it,most spectator/ riders who have theirs tested seem to know for a fact they don't work-especially while they're looking at the printout while their buddies laugh at them.Go figure.

[msambuco]

I would want a brand new 83 CR125, an 84 CR250, and an 87 CR500. I know they arn't as good as I remember but then neither am I. BTW the 84 CR250 is still the fastest 250 I have ever ridden.

[JETZcorp]

If you put a bunch of bikes on one dyno in one day, with all those variables lined up, then sure you'll get fairly accurate results to compare.  But when you start comparing numbers that are separated by twenty years, and those numbers say that a YZ426F should be 25% faster than another bike, yet is blatantly slower in the real world, there's got to be a problem in there somewhere.  It's also possible for a dyno to post a big number for a bike, that is the result of an almost totally unusable powerband, like the '81 CR450.

Ultimately, I think the ideal measure of a bike would be to create a sort of "Nurburgring of Motocross;" a gruelling and massive track that tests all factors of a bike, with sand and flat-out straights and big hills and off-cambers and slimy mud and big whoops and small whoops and sail-through-the-air-jumps and the whole works.  No metric of performance is going to be perfect, but the 'Ring seems to be fairly well accepted for performance cars, so I think a similar approach would be great for motocross as well.  Now we just need someone crazy enough to make a track with ten-minute lap times.

[ford832]

  Now we just need someone crazy enough to make a track with ten-minute lap times.

That's too easy.Take your average MX track with about a 1.5 min lap time and put an old Maico on it.There's your 10 minute lap time

Dyno's have zero to do with usable hp or rideability.They simply measure true hp at a given rpm and peak.
Reasonably speaking,they are reasonably accurate,more or less,most of the time

[SachsGS]

Ford I think you made a typo there, with an old Maico it's 10 LAPS PER MINUTE.

[ford832]

Lol.I really need to find a way to yank Jetz's chain a little without lumping in you,opfermanmotors,maicoman etc.In the meantime,you're all together

[JETZcorp]

Don't worry, my chain has had the shit yanked out of it by the good old air-cooled.  Your yanking efforts were hardly noticed.

[SachsGS]

Jetz's membership is presently under review, at the next Klan meeting we'll see what the wizard has to say.

[JETZcorp]

You fool!  I AM the wizard!  Pay no attention to the bespectacled teenager behind the computer screen.

[JohnN]

Jetz at work.......