2 stroke thread (with occasional F1 relevance!)

[Andres125sx]

A-125 is incorrect about 2T tractability, since GP bikes running at up to ~440hp/litre were clearly rideable.

Rideable? Yes, obviously, but effectiveness, or traction wich is the most important factor about how an engine make the most of each bhp, was miles away from 4t´s

That was main problem of 500 2t vs 4t, they lacked tons of traction. If my memory serve me well, drivers said first 4t bikes had so much traction compared to 2t it was like riding with TC, wich is exactly the same experience I´ve had comparing my KX250 2t with any 450 4t I tested, like if they have TC

Now they can say they miss 2t... 4t are too easy.... and all they want, but give them the chance to choose for next GP between best 500 2t ever and worst MotoGP ever, and they´ll chose 4t hands down

Fun is for amateurs, for racing it´s efficiency what counts

The fact remains that the 250cc 4T Moto 3 replacement for 125cc 2T GP is still slower around the track..

As I said, for low power aplications the traction advantage 4t engines provide doesn´t apply, it´s for high power applications where 4t shine vs 2t. But you know it, that´s the reason you ignored Moto2 and MotoGP for this fast lap comparison and only mentioned Moto3

[J.A.W.]

A-125, it seems you are ignoring the obvious..

Moto 2 600 4Ts still remain slower than GP 250 2Ts, even around fast tracks like Phillip Island.
Even after years of trying..
Nor are those fat porkers much good for developing rider skills..

Moto GP does have traction control, both by direct electronic,
& by defacto low tune/specific output - compared to 2Ts.. ..C. Stoner used as little E power-culling - as he could..

This dumbing down of the sport, really only serves to make WSBK look good..

[Cold Fussion]

J.a.w, what' are your thoughts on that Ricarfo engine that can operate on a 4t or 2t cycle?

[J.A.W.]

Well C-F, ask yourself..
..if in a hard on race, or other max power output scenario.. ..which mode - 2T vs 4T - would you want?

[uniflow]

A-125 is incorrect about 2T tractability, since GP bikes running at up to ~440hp/litre were clearly rideable.

Rideable? Yes, obviously, but effectiveness, or traction wich is the most important factor about how an engine make the most of each bhp, was miles away from 4t´s

That was main problem of 500 2t vs 4t, they lacked tons of traction. If my memory serve me well, drivers said first 4t bikes had so much traction compared to 2t it was like riding with TC, wich is exactly the same experience I´ve had comparing my KX250 2t with any 450 4t I tested, like if they have TC

Now they can say they miss 2t... 4t are too easy.... and all they want, but give them the chance to choose for next GP between best 500 2t ever and worst MotoGP ever, and they´ll chose 4t hands down

Fun is for amateurs, for racing it´s efficiency what counts

The fact remains that the 250cc 4T Moto 3 replacement for 125cc 2T GP is still slower around the track..

As I said, for low power aplications the traction advantage 4t engines provide doesn´t apply, it´s for high power applications where 4t shine vs 2t. But you know it, that´s the reason you ignored Moto2 and MotoGP for this fast lap comparison and only mentioned Moto3

You are right, fourstrokes are easier to ride and I see them everywhere on trail rides / enduros now. But it is interesting to note that when the chips are down and it's steep, slippery, or just generally difficult the older twostroke riders seem to have the skills to get through. I see ( younger ) fourstroke riders everywhere rapidly run out of ideas when they lose traction. I know this is just a generalisation but it's what I see. I've ridden a YZ250F a lot, it just makes me lazy.

[Andres125sx]

You are right, fourstrokes are easier to ride and I see them everywhere on trail rides / enduros now. But it is interesting to note that when the chips are down and it's steep, slippery, or just generally difficult the older twostroke riders seem to have the skills to get through. I see ( younger ) fourstroke riders everywhere rapidly run out of ideas when they lose traction. I know this is just a generalisation but it's what I see. I've ridden a YZ250F a lot, it just makes me lazy.

Agree on this. Two strokes are best posible riding school, can´t agree more as a two stroke fan myself who get shocked when people with 4t strugle on slippery zones... what if they´d be riding a 2t on that same zone then?

2t does teach you what to do to improve traction (weight transfer, bike lean angle, searching for bankings....) so you learn more than with any 4t, as you say they make you lazy, you don´t need to work as hard.

But 2t make you learn better and faster because of its own limitations, so I don´t think this may be argued as a positive aspect of two strokes

If I want my son to be a rider, learning with 2t would be better, but for the matter of the thread, 4t are better than 2t on any aplication where traction matters

[Andres125sx]

A-125, it seems you are ignoring the obvious..

Moto 2 600 4Ts still remain slower than GP 250 2Ts, even around fast tracks like Phillip Island.
Even after years of trying..
Nor are those fat porkers much good for developing rider skills..

Moto GP does have traction control, both by direct electronic,
& by defacto low tune/specific output - compared to 2Ts.. ..C. Stoner used as little E power-culling - as he could..

This dumbing down of the sport, really only serves to make WSBK look good..

This is fun, you´re comparing 250cc, a free development category with Aprilia, Honda, Yamaha, KTM fighting for the title as as some tire manufacturers did, with an almost spec category with just one engine supplier and one tire supplier, but it´s me who ignore the obvious...

[J.A.W.]

Funny, A-125, but I think the downvoting began just 'bout the time you chimed in.. rolleyes..("obvious")..

& you still fail to grasp the fundamental concepts..
..with your flawed ideas apparently based on your limited/anecdotal experience of dirt bike play riding..

Those with skills indeed prefer the lively snappish response that a proper performance 2T provides..

As previously emphatically stated, & by reason of irrefutable thermodynamic logic, only when 2Ts are..
..seriously handicapped by "rules" or as in actual fact - outright bans - can they be beaten by 4Ts..
.. for high speed, high power, road racing..

The 250 GP class was limited to 2 cylinders & 6 gear ratios.. it was replaced by a 600cc 4 cylinder 4T, 6-speed..
..production based sure, but with 25+ years of supersport racing development, & also with free chassis reg's..
Yet they are still slower..

Your expressed opinion of a potential 3 litre V12 2T of 900hp being "undriveable"..
.. simply betrays your limited (& incorrect) comprehension of the subject..

Since if the narrow single track footprint of a bike can effectively transmit the ~440hp/litre,
an F1 chassis, with dual fat slicks & bulk aero-downforce too, certainly could..

[Andres125sx]

Funny, A-125, but I think the downvoting began just 'bout the time you chimed in.. rolleyes..

You may think what you want, but that doesn´t change you´re wrong

& you still fail to grasp the fundamental concepts..
..with your flawed ideas apparently based on your limited/anecdotal experience of dirt bike play riding..

My experience is unknown for you, so please stop talking about things you ignore

Those with skills indeed prefer the lively snappish response that proper performance 2T provides..

Source?

Some driver statement saying "real men prefer 2t" doesn´t change reality, wich is when they could choose between 2t and 4t, every top team and every top driver chose 4t

The 250 GP class was limited to 2 cylinders & 6 gear ratios.. it was replaced by a 600cc 4 cylinder 4T, 6-speed..
..production based sure, but with 25+ years of supersport racing development, & also with free chassis reg's..
Yet they are still slower..

I know you´re smarter than you seem to demostrate here jaw, a century of development doesn´t change if there´s no competition, no manufacturer will take any single risk about their product, and they will be extremely conservative wich means perfomance will be lowered

Both at the engine side and at the tire side, two parts with some relevance in laptimes, can you agree on this?

[J.A.W.]

A-125, you have clearly shown the limits of your ability/knowledge 2T-wise..

& Naturally the factory contracted riders were directed to ride what the factory decided..
..how can you not realize this.. ..the Manufacturers also ceased development of the 500s too..( rolleyes)..

The real spirit of competition.. ..was lost from GP bike racing when 2Ts were banned..

2Ts could provide more exciting racing in a far lighter, less expensive package for F1 too, if allowed..

[Andres125sx]

A-125, you have clearly shown the limits of your ability/knowledge 2T-wise..

May I ask what´s your experience riding/driving 2t machines?

Theory is beautiful, but it´s not real world experience

& Naturally the factory contracted riders were directed to ride what the factory decided..

Once more.... source?

Please do not confuse your thoughts with reality, riders do prefer 4t, at least for competing, for fun it´d be debatable, but when laptimes count 4t rules..... for high power applications

[flynfrog]

http://motocrossactionmag.com/news/moto ... 2001-cr500 ill just leave this here. I do love my 2ts but but a 4t is much easier to ride and faster around a track.

[flynfrog]

also this

http://www.vitalmx.com/forums/Moto-Rela ... R500,60661

[J.A.W.]

A-125, you need to learn a few realities..

As for "high power" - the specific output of Moto GP 4T is less than what 2T roadbikes were making, decades ago..

The showroom production Aprilia RS 250 (Suzuki engine) was rated at ~70hp, or ~280hp/litre..
..more specific output than Moto GP..

Of course a similarly - fairly tamely - tuned 2T 1000cc GP bike could exceed that figure, & still be a fun ride,
while much lighter & less dependent on electronic aids, yet readily out-perform 4T Moto GP machines..

Google the statements of V.Rossi & C. Stoner regarding the matter, including why they left certain
manufacturers.. ..you will see that what I wrote previously is accurate.

I have owned, operated, raced, & tuned..
..many 2Ts over many years, I still have a number of multi-cylinder machines up to 750cc, & my last dirt bike
was a KTM 380.. ..(I regret selling it, but it was not getting enough use, & went to a keen buyer)..

Edit: Note the Aprilia RS 250 road bike used a Suzuki engine - different from the race mill, but still a goer..

[J.A.W.]

http://motocrossactionmag.com/news/moto ... 2001-cr500 ill just leave this here. I do love my 2ts but but a 4t is much easier to ride and faster around a track.

Thanks FF,

Easier = boring?

"Faster around a track" - that kinda depends on the track, & the rider, as the article reports..
& to be fair - the CR 500 was a very basic `80s-90s design that really hadn't seen much development in its final years,
- yet was/is still capable of providing a pretty good account of itself..

As noted a bit earlier ( recent posts - on the 'Engine Technology Free-for-all' thread)..
IMO, a modern-current 2T design of ~400cc that incorporated the various functional improvements
seen in smaller capacity classes - would have to do better than a big ol' CR/KX 500 blunderbus, fun as they are..