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Offline ChrisMX3417

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HOPE FOR 2 STROKES!
« on: May 31, 2011, 09:44:12 AM »
Direct injection 2 Strokes creates a 4-stroke powerband. For most people that is better. But like you many people like that hit. With DI you can have different power curves. It is possible to make a powerband that is narrower than a current carb 2-stroke! Aprilia made a DI RS250 and did this. They had easy power curves, aggressive curves, and curves that emulated carbureted 2-strokes. it would be very easy to have a switch on the handlebar that let the rider choose between them for his preference. Say if someone made a V4 500 Motogp(Sport bike) 2 stroke with Direct injection, You can even make it harder hitting than the current carb 2 stroke sport bikes or make it smoother like a 4 stroke and the emissions are lowered to 80 percent on the Direct injection and the 500 V4 motogps where making 210 bhp in 2001 imagine how much more it would have with Direct injection

Offline Suzuki TS250/185

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Re: HOPE FOR 2 STROKES!
« Reply #1 on: May 31, 2011, 10:54:51 AM »
No thanks....

1 REAL power curve is better than push button selection from a pool of fake ones.

My Yz's power curve is a miraculous expression of tuned induction and resonance. A DI 2 stroke's fake power curve is a weak imitation of the real thing, kind of like a blow up doll.

I think DI sucks and is a step backward for any motorcycle and I'll have simple, fast, bullshit free engines forever even if I get stuck casting the parts myself someday.







I think 4 stroke dirtbikes are a phase, kind of like "Glam Rock" in a way. You see the whole world subscribing to it, and you wonder how everyone could be choking down so much Kool Aid and Spam... Then 10 Years later, nothing's left but the timeless stuff from before and after..

Offline factoryX

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Re: HOPE FOR 2 STROKES!
« Reply #2 on: May 31, 2011, 12:04:25 PM »
Wowsers another DI thread. ;D And it is the way of the future, but some people aren't ready for it.


I ride an 03 yz250, wait 04, wait 05, what ever, they're all the same #$@% YOU!

Offline CCOADY454

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Re: HOPE FOR 2 STROKES!
« Reply #3 on: May 31, 2011, 12:14:00 PM »
Yeah, I don't like it, because it's just going to make a 2 stroke EASIER to ride, much like a 4 stroke.  Less skilled riders will benefit (good or bad??).  It's great for leveling the playing field against 4 strokes, but when you start adding too much programming, it takes away from the roots of the sport.  It'll just increase the overall expense, unless it's a mechanical direct injection.  It's pretty much the motocross version of traction control, in a way.  I'm sort of on the fence about it.

Offline TMKIWI

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Re: HOPE FOR 2 STROKES!
« Reply #4 on: May 31, 2011, 01:45:57 PM »
You guys are forgetting why a 2 stroke has a power band in the first place.
The way a motor is ported and the expansion chamber effects when the "powerband" kicks in.

Remember a 2 stroke is an "air pump" that works best when in the rev range the motor is designed for.When in its correct operating range a 2 stroke is a very efficient motor but when  running below that range is a very inefficient motor. Hence we have a very noticable "hit" when the revs climb into the designed operating range.

With a DI you will still have a powerband as the scavaging and exhaust pulses combine to increase volumetric efficiency."On the pipe"
You will have a smoother bottom end with DI because of better fueling but you still wont have volumetric efficiency.
It will be easy to have different mapping( like GG & KTM do now with ignition timming ) but by changing timming & fueling.
Any one riden a 250F lately ? they have a power band it is just not as noticeable as a smoker.
If you don't fall off you are not going hard enough

Offline factoryX

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Re: HOPE FOR 2 STROKES!
« Reply #5 on: May 31, 2011, 02:07:48 PM »
TMKIWI, stop repeating yourself, they don't get it.


I ride an 03 yz250, wait 04, wait 05, what ever, they're all the same #$@% YOU!

Offline miedosoracing

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Re: HOPE FOR 2 STROKES!
« Reply #6 on: May 31, 2011, 02:41:32 PM »
According to the KTM video, Fuel Injection will be first with them. Sounds like they have it already, but don't want to complicate things (yeh) until they absolutely have too. Said offroad first and then SX models if the governments force them into it. But the good news, is they are committed to them, and said see a day when they are back. 
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Offline 2T Institute

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Re: HOPE FOR 2 STROKES!
« Reply #7 on: May 31, 2011, 02:52:15 PM »
Direct injection 2 Strokes creates a 4-stroke powerband. For most people that is better. But like you many people like that hit. With DI you can have different power curves. It is possible to make a powerband that is narrower than a current carb 2-stroke! Aprilia made a DI RS250 and did this. They had easy power curves, aggressive curves, and curves that emulated carbureted 2-strokes. it would be very easy to have a switch on the handlebar that let the rider choose between them for his preference. Say if someone made a V4 500 Motogp(Sport bike) 2 stroke with Direct injection, You can even make it harder hitting than the current carb 2 stroke sport bikes or make it smoother like a 4 stroke and the emissions are lowered to 80 percent on the Direct injection and the 500 V4 motogps where making 210 bhp in 2001 imagine how much more it would have with Direct injection

Was only rumoured Aprilia made a injected RS 250 even my contacts in th Aprilia Corse said they had never seen that bike. The Suter 500 is injected but replacing carbs not the venerated Direct Injection. You can do all that with an ignition.The 500's didn't need any more HP what they strived for (as with all race bikes) is X % throttle = X % torque to the wheel.

Offline Kodackamera

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Re: HOPE FOR 2 STROKES!
« Reply #8 on: May 31, 2011, 02:55:35 PM »
Perhaps after a few years of DI, more work can be done developing them and tuning them when they emerge in racing for example.

Two strokes need something to start back on again, at least they will start again with something. Nothing happens overnight. Kaaden didn't stop developing chambers through all his difficulties, he could have flopped because it was difficult to start off.

The most highly tuned engines are rarely the smoothest. Imagine the potential in the future, after development wait till they get multi-cylinder designs rolling!

How will any development take place if people mention "It's D.I. it's not the same as it was" that is what will harm the two stroke much less a smooth powerband. Nothing's the same as it once was, at every moment in the world, things change, if we don't, we get left behind, so we may as well make the changes our way.

It's up to us, fans, designers, technicians, racers, to make it happen.

Generally, variable exhaust and intake geometry limit maximum flow of gas that would otherwise be attainable. For example, traditionally, Disc valves offered more maximum performance over reed valves. Two stroke engines of the future may well use variable geometry, but variable to different degrees...They need not be the same from scooter to sportsbike to enduro. The exact same throttle bodies and butterfly designs need not be fitted to every single D.I. two stroke. Mechanical limitations always apply regardless of "the evil/magic of the computers!!"

Even if sportsbikes were restricted, who's to say people could not develop components and systems to make the engines shine! People, especially over a certain age, fear the electronics and the advance of them (no pun intended), when you consider that the average person is likely to become more computer literate in the future, I see that in a small way, power can be given back to the average person/enthusiast as the cycle comes back and we understand what we are dealing with. It's up to us.
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Offline SachsGS

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Re: HOPE FOR 2 STROKES!
« Reply #9 on: May 31, 2011, 02:58:52 PM »
Let's see,the BRP DI 2T 600 sleds are making as much power with better fuel economy then the Yamaha 1200 4$ snowmobiles.I like where DI is going and look forward to buying a DI 2T dirt bike. ;D

Offline Suzuki TS250/185

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Re: HOPE FOR 2 STROKES!
« Reply #10 on: May 31, 2011, 03:33:48 PM »
Maybe some people here don't understand why there is a perceptible steepening of the power curve, or "Powerband" in a bracket of the RPM range, but I do. Some people never get the hang of riding the incline of that wave of power, but most riders understand it instinctively.

I don't mind if they make fuel injected bikes with some retardedly complex system of pumps, sensors and highly pressurized central processing butterfly gadgetrons... AS LONG AS PEOPLE WHO DON'T WANT OR NEED TRAINING WHEELS ON THEIR ENGINE can get the simple, brutally effective machines THEY want.

If the power characteristics of a good 2 stroke race bike are to harsh and uncouth for some people, let them get one of the DI bikes so they can put in a "mellow power band" CD in and putt around if they want. Nerf balls and blow up dolls if they want, just don't force that on everyone. They already make bikes with engines that have very little personality, and most of the time there are plenty of them left sitting around for sale cheap since lots of people aren't interested...

Sell both and no one will have a problem with DI bikes. Otherwise, those of us who still want the real thing will have to figure out a way of cutting all that stuff out and tossing it, or just changing the engines out altogether.
I think 4 stroke dirtbikes are a phase, kind of like "Glam Rock" in a way. You see the whole world subscribing to it, and you wonder how everyone could be choking down so much Kool Aid and Spam... Then 10 Years later, nothing's left but the timeless stuff from before and after..

Offline citabjockey

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Re: HOPE FOR 2 STROKES!
« Reply #11 on: May 31, 2011, 08:00:40 PM »
Have you had a 2-stroke with water cooling? With a variable exhaust port? With electronic ignition? All these are "modern" enhancements of the basic two stroke design and non of them take away from the need of an expansion chamber tuning the exhaust pulses to shove more fuel air mixture back into the combustion chamber before the exhaust closes.

NONE of that changes with DI. The method of bringing air into the cylinder remains the same. Up stroke sucks it into the crankcase, downstroke pressurizes the case and then shoots the air up into the cylinder as the transfer ports open. NOTHING DIFFERENT HERE. Only difference is there is not any gas in that air in the crankcase (side advantage here, no gas washing away any lube oil in there so don't have to use as much!).

The injector can time the fuel introduction to the cylinder to do that AFTER the exhaust closes so none of it shoots out the port without being burned. Efficiency just went up 30% with that little trick. Everything else works as a regular old DT1 engine. So, we need a computer to run it and a couple of sensors we are not used to. Big deal. 20+ years ago radiators and thermostats were new fangled toys.



No thanks....

1 REAL power curve is better than push button selection from a pool of fake ones.

My Yz's power curve is a miraculous expression of tuned induction and resonance. A DI 2 stroke's fake power curve is a weak imitation of the real thing, kind of like a blow up doll.

I think DI sucks and is a step backward for any motorcycle and I'll have simple, fast, bullshit free engines forever even if I get stuck casting the parts myself someday.








Yamaha CT3, RT3, MX125, SC500, Toy Prius, Diesel F250 (it all balances out)

Offline Suzuki TS250/185

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Re: HOPE FOR 2 STROKES!
« Reply #12 on: May 31, 2011, 09:01:36 PM »
Yes, but that 30% might be important to you. It's not important to me. I don't care at all if a little tiny bit of the fuel charge is lost here and there. All I care about is how the bike runs.

When my bike runs out of gas, I put more in it. If that happens 30% sooner, I don't care.





I think 4 stroke dirtbikes are a phase, kind of like "Glam Rock" in a way. You see the whole world subscribing to it, and you wonder how everyone could be choking down so much Kool Aid and Spam... Then 10 Years later, nothing's left but the timeless stuff from before and after..

Offline chump6784

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Re: HOPE FOR 2 STROKES!
« Reply #13 on: May 31, 2011, 09:35:15 PM »
With the power increase that DI offers it could make two strokes competitive against 450's therefore taking out any handicap. I did say could, the results will have to be seen but this could be a real winner

Offline ACMX

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Re: HOPE FOR 2 STROKES!
« Reply #14 on: May 31, 2011, 10:36:08 PM »
Oh dear lord, if the AMA continues on they track they are heading down, they will probably change the rules for DI two strokes. 125 two stroke against 450 four strokes.
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