A new two-stroke 500cc Ronax

[Alby46]

honda always insisted on using 4 stroke engines: the nr500 is an example. And the decisional power increased over the years from its born, and at the end of the 90s they've got so much decisional power that they imposed 4 stroke to the whole world... ok that's my opinion lol

[HornetMaX]

Alby, honda can't impose anything on the market. Maybe they can push for stuff in racing, but surely not on the market.

I don't know why honda preferred 4 strokes at the time (notice, the nr500 was an absolute flop), but from what we can see now, they were pretty much right.

MaX.

[Alby46]

they like 4 strokes, and i can't understand why they went so on with 4 strokes

[Vini]

If it was worth, they would take the risk, trust me. For sure some smaller player (ktm ? bmw ? ducati ? you name it) would be more than tempted to outsmart the japs with a better, lighter and cheaper 2 stroke engine. But at the moment it seems just not possible.

It's not possible in the time you expect it to be and that is why no manufacturer even thinks about investing money into it.
Creating a working direct fuel inject two stroke with high torque and low fuel consumption (snowmobile engines) is one thing but making it produce as much power as regular carbureted two strokes is a completely different problem that will take years if not decades to solve.
I understand your point, you want a fast road bike and not a race bike but because this second problem is not yet solved, the advantages over four strokes are simply too small.

Now, if two strokes were still be raced in MotoGP, these developments would have happened because there would not have been the option to be 'lazy' and switch to four strokes and accept more weight and less power.


But, in the end, a two stroke engine has the most potential and ultimately is the better engine. It just needs the 30 years of development that have been lost when the big manufacturers abandoned it.

[HornetMaX]

It's not clear at all. As soon as introduced in motgp, 4 strokes were faster. Immediately, from day zero. Despite the weight, despite the engine complexity.

And race bikes, especially for Honda but true for the others too, are seen as a lab for road bikes (Honda & co make money selling bikes, not winning races).
Racing with 2 strokes just for the fun of it (knowing this will not lead to 2 strokes road bikes) just makes no sense.

I was talking about road bikes because you seem to think that in races Honda imposes his law (4 strokes). But on the market there's no such a thing.

But again, some people are making experiments with two strokes: I have zero doubts that if the technology of 2 strokes becomes better than 4 strokes, constructors will switch to it. Including Honda.
And riders too. Including me.

MaX.

[Alby46]

i remember mcwilliams risked to finish on the podium with the 3 cylinder kr500 in 2003, mccoy setting the pole at phillip island in 2002, many podiums in the same year, and the development of these bikes was stopped 2 years earlier, simply because they knew they were going for 4 stroke

[HornetMaX]

Yes but the development of 4 strokes just started while 2 strokes had been in use for a while. On year zero of 4 strokes era, 4 strokes were faster than 2 strokes that have been around for a while.

MaX.

[Vini]

With double the capacity you don't need any fancy technology to get more power than an outdated 500cc two stroke.
And who even set those limits, a 600cc two stroke for example would have had more power than the 990s and today would even come close to what the MotoGP bikes are producing.
Besides, four strokes didn't start at zero in 2002, superbikes have been around a little bit longer.


But with the manufacturers being lazy, I was referring to road bike development. With no reason to put any money into two stroke development because they are not raced in MotoGP anymore, they didn't see the need to build road bikes with the best power-to-weight ratio possible (which would require a two stroke engine) and accepted the weight gain and power loss compared to a hypothetical, highly developed V4 two stroke.

Racing with 2 strokes just for the fun of it (knowing this will not lead to 2 strokes road bikes) just makes no sense.

I agree, that's why there should have been some rules, like today, to limit fuel usage or even make DFI mandatory directly.
The same is happening in F1 right now.

[HornetMaX]

With double the capacity you don't need any fancy technology to get more power than an outdated 500cc two stroke.

Why outdated 500cc two strokes ? They were the top-notch 2 strokes available at the time (competing against top-notch 4 strokes available at the time).

Also the double of the capacity stems simply from the fact that a 2 strokes fires once per cycle while a 4 strokes fires once every two cycles. As simple as that, it's not a "I like to win easy" thing: the double of the displacement puts them roughly on par in terms of fuel usage (and hence power).

But with the manufacturers being lazy, I was referring to road bike development. With no reason to put any money into two stroke development because they are not raced in MotoGP anymore, they didn't see the need to build road bikes with the best power-to-weight ratio possible (which would require a two stroke engine) and accepted the weight gain and power loss compared to a hypothetical, highly developed V4 two stroke.

You get it wrong man. They invest in races because it may bring advantages to road stuff, not the other way around. If today they are not investing in 2 strokes, it's surely not because motogp is not using them. They invest in plenty of things that are of absolutely no use in races.

Once again, if it was possible to make a 2 stroke engine that is lighter, cheaper and at least on par in terms of power and emissions, they would absolutely love to have it. For road bikes, because that's what they sell.

I agree, that's why there should have been some rules, like today, to limit fuel usage or even make DFI mandatory directly.
The same is happening in F1 right now.

You seem to imply that a 2 strokes is more efficient, which as far as I know is not necessarily true.

MaX.

[Vini]

Why outdated 500cc two strokes ? They were the top-notch 2 strokes available at the time (competing against top-notch 4 strokes available at the time).

Because they were not nearly producing as much power as they could have done because they had to be ridable. From the beginnning of the 90s the 500s didn't become more powerful anymore because there was no TCS to control such a beast.
In the other classes development was still going and horsepower improved every year.

Also the double of the capacity stems simply from the fact that a 2 strokes fires once per cycle while a 4 strokes fires once every two cycles. As simple as that, it's not a "I like to win easy" thing: the double of the displacement puts them roughly on par in terms of fuel usage (and hence power).

You that it's not as simple as that: A two stroke needs more stroke to have a proper gas exchange, thus lowering the maximum rpm.
For smaller engines it is true though and that is why the last 125s had more power than todays Moto3 bikes.

You get it wrong man. They invest in races because it may bring advantages to road stuff, not the other way around. If today they are not investing in 2 strokes, it's surely not because motogp is not using them. They invest in plenty of things that are of absolutely no use in races.

That is what I am saying. If two strokes with mandatory DFI, fuel and emission limits were still raced in MotoGP then they could eventually use this on street bikes and they would invest in it.
Of course, simply going back to carbureted two strokes from the 80s will end up the way it did in the 90s: Unusable for the street so they build four stroke street bikes.

Once again, if it was possible to make a 2 stroke engine that is lighter, cheaper and at least on par in terms of power and emissions, they would absolutely love to have it. For road bikes, because that's what they sell.

Once again, the time and money needed to make powerful two stroke engines suitable for road bikes can only be justified if they need to to do it in order to compete in motorsports.

You seem to imply that a 2 strokes is more efficient, which as far as I know is not necessarily true.

If you are talking about 30 years old motorcycle engines, then yes: They are not necessarily efficient (at least not in terms of fuel usage-to-power output, in terms of weight/size-to-power output they of course still are). But again, the magical technology is DFI: You don't have wasted energy (fuel exiting through the cylinder) and remaining are the advantages of lower moving parts (and parts in general), smaller size (and less weight) and lighter moving parts which makes the engine more efficient. There is a reason the most efficient internal combustion engines are turbocharged direct fuel injected two stroke diesels.

[HornetMaX]

You get it wrong man. They invest in races because it may bring advantages to road stuff, not the other way around. If today they are not investing in 2 strokes, it's surely not because motogp is not using them. They invest in plenty of things that are of absolutely no use in races.

That is what I am saying. If two strokes with mandatory DFI, fuel and emission limits were still raced in MotoGP then they could eventually use this on street bikes and they would invest in it.

No that is not what you're saying. You are saying that they should impose/allow 2 strokes in motogp, so that in x years we may have something for the road. But nobody at the moment is convinced by that.

What I am saying is that the move from 2 strokes to 4 strokes happened exactly because road bikes were 4 strokes, and for good reasons, so racing with 4 strokes makes sense for the constructors.

What you're saying is: I like nuclear propelled bikes, let's make them mandatory in racing so that maybe one day (despite what all the constructors are saying and doing, not only honda), we'll have nuclear propelled road bikes. Because I think they are better/funnier/cheaper/lighter. You'll need some pretty heavy arguments to convince even KTM to do that, cause at the moment they don't think it is worth. But if you have the arguments ready (and some people are definitely working on this), then the constructor will listen.

MaX.

[Vini]

The only difference is that two strokes are nothing new and the oppurtunity was there to start new developments and there was enough time to perfect the new technologies but instead the development froze and nobody did anything against it until two strokes were outdated and replaced by four strokes.


Besides, the Rotax DFI engines are already quite powerful, with the budget of a factory MotoGP bike it would probably not take very long until the bikes produce some serious power.
But, to repeat myself, without there being an urgent reason to invest into it at the moment, no manufacturer will simply spend a couple of millions per year.
It's the same reason why fully electric cars are taking so long to take over the car market.
As you can see on the Tesla, the technology is there but even then no big company sees the reason to build fully electric cars.

[Alby46]

https://www.youtube.com/watch?v=XIcX9-GsMGQ

[HornetMaX]

As you can see on the Tesla, the technology is there but even then no big company sees the reason to build fully electric cars.

I am a big supporter of electric vehicles (including bikes, many here know it from past discussions), but the technology for electric cars (or bikes) is not fully here yet. Still some things to work on.

But the big difference is that in the case of electric vehicles everybody knows who is really unhappy about them (and it's not the car makers).
For the 2-strokes vs 4-strokes debate, there's no such an unhappy big player with a valid reason (from his point of view) to kill one solution or the other.
So it's really hard to explain why a (supposedly) better solution is not coming out, as nobody seems to have anything to lose with it.

MaX.

[Vini]

If somebody develops and manufactures a bike with 200 hp and 130 kg but nobody even dares to ride it or doesn't want it because it's a 'dirty two stroke', this company will lose a lot of money.
A two stroke is for people who want the absolute best performance available, as you said yourself, for the average rider it doesn't matter whether you have a superbike with 200 hp and 180 kg or the same at 130 kg - he can't use the full potential either way and both bikes are extremely fast.
But for the ones who want to be the fastest on the track and have the required (very high) skills, this bike will be the top choice once they are also able to ride it through traffic with reasonable reliability and fuel consumption.
For every other person who just wants a fast road bike, a V4 two stroke doesn't make any sense because it's full performance can't and shouldn't be used on road.


The perfect motorcycle is a highly developed two stroke but most people don't need and/or want the perfect motorcycle.
The demand in the general public and the profit of the manufacturers is simply too small to justify the development of a high-tech two stroke.