All 2st Jody's 2stroke manifesto

http://www.motocrossactionmag.com/M...DYS-MANIFESTO-OF-AN-UNREPENTANT-TWO-7970.aspx

Truth.

All that and not one word about the Husky 250 /300
I am one who made the mistake back in 1975 yes 1975 when i sold my Suzuki TM250 2 stroke and got a 1975 Honda XL
250 in a C&J Fram Rode 4 strokes until 2006 when for some unknown reason i test road a Husky CR 125 and felt stubid for not doing so many years earlier.Since 2006 my Husky TE510 gets rode only a few times a year and all my Husky 125 250 and now a 300 get rode almost every day .If they never made a new 2 stroke again i could ride what i have for ever before i purchased a 4 stroke again

TC150??

sweet mullet on the Hodie.

good read!

BRING BACK THE BRAAAP!

really hard to deny the cold facts of the Ed.... I love my 2 strokes, but will still ride a 250f.

Very good read and like Krieg said "TRUTH". Three of our four bikes are 2-strokes and the other is a 2010 TC250 which we ride like a 2-stroke LOL. Thanks for the post up.

Good reading find! That Fantic looks pretty cool?

The author kind of admits being an author is his occupation and make your own conclusion. I find the article misleading. Why did the two stroke drop out of favor as a road racer? Why were they making crankshafts with the firing pulses 15 degrees apart towards the end? Why did it become that the 250 two stroke bikes went around the moto cross track faster than the 500 ones? I havn't had a magazine subscription for perhaps 10 years but I think the answer is the type of power they make at less than fully twisted to the stop. I watched (spectated) for a pro event at Southwick a number of years ago and was amazed that the bikes were not running wide open. They must have twisted it all the way before jumps but even that was hard to be sure about. The guys which fell over on the four strokes would kick until they couldn't kick any more and get pushed off the track but the top guys didn't seem to fall over.

I have also kept an eye open to the ISDE results looking at the times for all the days added together and it seems pretty much if you look at everyone within the top two minutes all kinds of bikes are represented.

Fran

The argument of 2t's are more confined to the dirt than the road where living with a 2t would like driving around in an F1 car.
Although GP Racing shares similarities with the motocross world in terms of phasing out 2t's, the key reason was manufacturer support. By the end of 2001 there were only four bikes that you could be competitive (be it a factory supported rider) on NSR500 or YZR500 and the RSW125/250 even though 4t's were always allowed to race in the GP world but you could not get the same performance in a similar capacity 4t (sound familiar) - to this day, a 2t can race in MotoGP but under the 500cc limit?
In the GP world, the 500cc 2t had reached it's end of life as race motor as it's was just about the perfect 500cc when Valentino last rode the NSR500 to victory.

The main factor was cost, manufacturers eventually saw no benefits in developing 2t's when the development could not be translated to the street..lets face it, a 4t roadbike is much more reliable and cost less then a 2t roadbike.

On power pulses, purely refined to get that balance of explosive power and traction. On a single cylinder 2t MX bike unless you are a factory team that can cast a crankshaft you leave the OE crank alone but on multi cyl 2t's, crankshaft timing is important (again if you are a factory team) but the blackart in 2t's are in exhaust port timing, power valve mods and more importantly, expansion chamber and exhaust length - altering power pulses to allow the rear tyre more time to recover between which results in better traction thus easier to ride or tuning the power band of the bike (ever noticed the beautiful custom expansion chambers on a GP bike!!) for each circuit they race.


Big bad 2t 500cc slower than 250ccc....the least powered 250cc was easier to ride fast by many than, like it's GP racing eqvilent, 500cc 2t whom only a handful of riders so they were killed off in the US scene when supercross started to take off - the last rider to win the World MX 500cc class was Shayne King on a KTM360 of all bikes.

As the author pointed out, the rule bias towards a 4t is the major factor why no manufacturer (in motorcross or GP Racing) would want to compete with a 2t..now if the rules were 350cc 2t vs 450cc 4t that would make interesting battles.

As to continue with the misleading theme I quote here.

(2) Four-stroke power: Four-strokes are not more powerful than two-strokes. Their horsepower and torque come from a common parlor trick called “cubic centimeters.” Four-stroke are only competitive with two-strokes because they are larger. Under AMA rules, four-stroke engines are allowed to be as much as 100 percent larger than two-strokes.

I presume the max a two stroke can be is 125 to go against a 250 four stroke is where the 100 percent comes from. I won't discuss that aspect. Looking at Husky, ktm, Yamaha they all seem to have settled into a 55.5 mm stroke and 72mm stroke for the 125 and 250. I recall Ducati had this desmo device to close the valves which was necessary over a certain rpm perhaps 8000 or so. The four stoke MX type of bike today have lots of timy valves and short stroke. Doesn't a modern 450 single MX bike have pretty much the same stroke as a two stroke 125? These two design features allow the four stroke bikes to rev farther and me to call this #2 misleading.

Let's agree that the four cycle makes one power cycle every 720 degrees of rotation and the two stroke makes one power cycle every 360 degrees of rotation. I can't seem to find a new pick up truck (gasoline) without variable valve timing but I don't think it has yet come to single cylinder dirt bikes. The four stroke engine generally has the valves (well exhaust one (s))open before the very end of the power 180 degrees of rotation and the two stroke presses down basically until the exhaust port is reached. I note the pulse in the two stroke especially with the power valve open is less and should be factored into the twice as often discussion. Where I find the modern two stroke amazing is with the power valves closed, take the ktm 200 (not adjusted like sx)for instance the most extreme example I have found. It has a 60 mm stroke and there is 47 mm before the push on the piston ceases to pull on the chain, and like you state it does that every revolution. The way the power goes away as the exhaust port becomes open might be a major factor of the type of power I mention in the first post in this string.

It's really this simple:

Q: WHICH BIKE MAKES THE MOST HORSEPOWER?

A: No comparison. A Yamaha YZ250F produces approximately 36 horsepower at 11,300 rpm, while a YZ250 two-stroke makes on average 46 horsepower at 8500 rpm. That is a ten horsepower advantage at peak for the two-stroke.

Q: WHICH BIKE MAKES THE MOST TORQUE?

A: Pit pundits will always tell you that horsepower doesn’t matter as much as torque. They wax on about the torque advantage that a four-stroke engine has over a two-stroke. Guess what? A Yamaha YZ250F four-stroke makes 20.1 foot-pounds of torque. Are you ready? A YZ250 two-stroke pumps out 30.6 ft-pounds. For comparison purposes a 450 four-strokes produces approximately 34 foot-pounds.

http://motocrossactionmag.com/Main/News/YOU-ASKED-FOR-IT-MOTOCROSS-ACTIONS-TWOSTROKE-VERSU-7117.aspx

I was interested to read Jody W's article on two strokes; but were not Motocross Action and the other dirt related magazines part and parcel of the transition? I haven't a clear cut reason it happened that 4-strokes took over but marketing is certainly a huge part, not to mention the amount of power the Japanese brands had in forcing the issue. Remember that old Jody doesn't like european bikes because in his view they don't handle properly or have the latest tech. support, he never has since the early 70's. I only mention this because although his main point is surely correct i would question his motives.
Anyway my 2 cents is that i'm glad that the Euro's are in the two-stroke mode, the CCM's i used to race were 20lbs. lighter than my last 4-stroke and went faster just not longer. Husky is set to open up a new page in the USA if they would put some effort in place for the Enduro scene. The 250 and 300wr's are everybit the match for the competition only lacking a 6 speed i mean that's it, we don't need FI or new frames just the trans. fix because the price is affordable and they are simple to own.
It should be noted that Jody said; and it's true that we only use maybe 20% of what's possible and he is spot on. Good read and thoughtful so we'll see.
Oh, gimme a fantic 300, i couldn't ride it as fast as it would go but it would look good.
Good Riding ........

Pat,

It would be interesting to see Husky offer a 6-speed kit for the 250/300. They have all the parts in the cubbard and it is a simple swap with some instruction. I really miss my WR250 with the 6 speed, etc. Kelly that essentially same bike is still competetive on the world stage. I still want an e-start for us short, old guys.

You too my bad.