Packaging power - 2T Vs 4T

[Lozza]

what i have noticed riding my 500 2 smoker against
modern 4 bangers is corner speed
i dont know how many times i have stalled or nearly stalled
or nearly hit 4 strokes mid corner
i find on the 2 stroke you tend more too ride the whole corner
where the 4 strokes stop and go and point and shoot
 took a helmet cam of a race and they seem to go like shit down the straights
brake early ride into corner square it and power out at a great rate of knots
where on  a 2 stroke you brake later get on power early and hold it through turn
thats why i nearly hit them no doubt they have great drive out of corners

 There in lies the problem to pass you knock off your corner speed, then allowing a repass on the exit.Get up the inside and hold them out wide Rusty A young fella at Kurri Kurri is flogging all the 250F's on a YZ 144 in Dirt Track gets holeshot and a 15m break at the first turn and they never catch him.

Frosty you can have traction control now if you want it.

[mainline]

MXA did an article a year or so ago, where they had a few riders of differing ability compare a  new CR450F to a 2001 CR500.

To cut a long story short, by the end of the testing they all wanted the CR500 engine in the CR450 frame. The ergonomics and suspension were the deciding factors in favour of the modern bike.

[JohnnyO]

There are plenty of 500 2 strokes getting around in alloy frames but no one is racing one competitively at a high level in motocross.

[Nathan S]

Is there even a class to ride a 500 2-stroke in, at State/National level MX?



Traction control for a performance application on dirt is actually VERY difficult.

[JohnnyO]

Is there even a class to ride a 500 2-stroke in, at State/National level MX?

Good question.. Not sure on the rules these days.

[holeshot buddy]

i would love to set my bike up for
a fast pro to ride i think he would be suprised

[090]

I think 500's are still too hard to ride. I would love to ride a 300 mxer. that might be the right amount of power. And a 200 for the lites then.

[monaro308]

what i have noticed riding my 500 2 smoker against
modern 4 bangers is corner speed
i dont know how many times i have stalled or nearly stalled
or nearly hit 4 strokes mid corner
i find on the 2 stroke you tend more too ride the whole corner
where the 4 strokes stop and go and point and shoot 

Thats what i found playing on the MX track,my cornering is all f@#$ed up now,i would approach the corner at a certain speed thinking about holding a nice line around the corner but with all the engine braking of the 450 it would haul the bike up too quickly and the front diving make a mess of my cornering.With the added high weight of the 450,my 72 kg body trying to turn a 120kg pig aint fun....like holeshot said,i end up at almost a stop,then trying to gas it out.

[Rossvickicampbell]

to ask a question - why does a 4T have more traction?  And Lozza - you say a 2T will have twice the tyre slippage because of 2 bangs per cycle but therefore won't it also have twice the drive per cycle?  I would of thought all of these would be due to amount of power being transferred to the ground - therefore 40 HP will slip x amount regardless of where from?

Now I know I aint right but why?

ta

Rossco

[All Things 414]

Is there even a class to ride a 500 2-stroke in, at State/National level MX?

It would be the Open class (450F) as it stands wouldn't it?

[Lozza]

Is there even a class to ride a 500 2-stroke in, at State/National level MX?



Traction control for a performance application on dirt is actually VERY difficult.

The hardware is a cinch, determining the the exact amount of wheels spin would be the hard bit. If road racing is a guide most of the fast blokes use settings 2-3 out of 10.So I suppose dirt would be between that and zero.
A few years ago there was an outdoor meeting that developed a large bog hole, all the riders were nailing it full on with their thumb on the 'button' activting the second retarded advance curve as a cheap and cheerful traction control.

[Tex]

imagine a 2t with traction control

Didn't the Yamaha DT230 have something like that? It also had electric start way before it appeared on the KTM EXC300 too.

Tex

[VMX247]

Opinions:A Good read:I know its not VMX ..but hey its Sunday   

Lightweight and ultra-responsive are great ways to describe the KTM 250 SX in the turns. It eats ruts for lunch.
It's been a while since I've ridden a two-stroke on a motocross track, and the KTM 250 SX definitely reminded me of how flat-out fast-and fun-these bikes are. Earlier in the day I'd been doing motos on 250Fs, and when I initially hopped on the two-stroke I proceeded to over-jump nearly every double and tabletop on the track. These things have power! In the KTM's case, the engine comes alive not with what I would describe as a hit but more with a surge; the low-to-mid-range delivery is incredibly strong but surprisingly useable. In fact, this RPM range was my favorite place to ride this bike, as venturing into the top end produces enough vibration to register on my internal Richter scale as "hazardous to dental work." Sure, you'll get this with any 250cc two-stroke, but why wring the bike out and rattle yourself to high heaven when you can just short-shift the bike and ride the useable wave of low-range meat? That's my thinking, anyway. Beyond the motor, this KTM feels extremely lightweight, yet it somehow still manages to get most of the power to the ground so long as you're in the ballpark of the right gear. It turns consistently well and handles chop decently, though I felt some kicking in the rear end that I couldn't quite adjust out with the rebound; I think I'm too light for the shock's spring rate. The fork springs were great for my weight but didn't quite work in sync with the rest of the motorcycle, causing the overall handling to suffer a tad. Nevertheless, I enjoyed playing around on this machine and came back to the truck with a huge (and, I'm happy to report, toothy) grin.
-Chris Denison/ 5'10"/ 155 lb/ Intermediate

If you want a bike that loves to have fun (in the air or on the ground) a 250 two-stroke is a solid choice. The 2010 KTM continually shows us why it's alive and well.
The simple fact about two-strokes is that they are making the same power as the four-strokes with half of the displacement. There is a disadvantage in the length of the power spread, with what seems about a little over half as long in the total length of RPM pulling time. Heck, two-strokes rarely rev over 10,000 RPM anyways. But there is a huge advantage in how light the bikes feel and how easy they are to throw around - thank the limited amount of centrifugal force spinning between your feet. And I can go on and on with comparisons and contrasts about which is better and which has advantages where. But in the current class structure, four-strokes have an advantage. So if you play by those rules, then the writing is on the wall. But if you live outside the constraints of some ridiculous class system and ride whatever you enjoy the most, then two-strokes make a lot of sense. Less maintenance, easier to service, less expensive, the list can go on. Though the choices are somewhat limited, KTM has continued to bring a first-class race ready bike to the table. I rode a '08 250SX for a whole year and only swapped it out for a 125SX in 2009. For 2010 the 250SX is as good as ever and one of the bikes I'd easily consider buying if I were more of a motocross racer. No, this wouldn't be the bike I'd be the fastest on or the one I'd win the most races on. But this two-stroke would be the bike I'd have the best balance with of being seriously competitive on (much more than on a 125) and having the maximum fun every time I rode.
Jimmy Lewis 5'10"/185 lb./Sr. Expert

[Freakshow]

Sold the KTM250 and rode a Yam250F last year, now its for sale as i bought another 2 banger - YZ250 ( before they stop making them)
the 4 stroker seemed to be a plusher ride and you could do more laps untired, but i couldnt get my head around the cornering and the engine braking on ramps.  I still cant get my head around i would have to ride up to 450 4t to race against a 250 2t - that tells you somthing about the power there.   

Ziiingggggggggggggg zinng

[All Things 414]

Good man Freaky. I gotta 2000 YZ 250 and they're the ducks nuts! You can buy all sorts of grouse trick stuff for the older ones (like mine) for peanuts....