All 2st The future of two strokes

[tommie d]

http://www.dirt-bike-tips-and-pics.com/future-of-two-strokes.html

It's kind of long but makes for some good reading.

 

[Drew Smith]

That is great stuff! Smaller lighter faster, I think the two strokes benifits are coming back into focus. lets hope misguided EPA regs dont ruin good engineering.

 

[highdez1981430cr]

WOW!!!

God bless KTM

TWO STROKES WILL RULE AGAIN SOMEDAY

 

[dfeckel]

I just spent half the morning reading that very compelling essay. I certainly do hope that the status quo (highly developed 4-strokes) doesn't prevent further development of the two stroke. I really sounds like the 2-stroke could return to the forefront of technological advancement.

Here's the take-home lesson--when KTM finally releases the DI 300, we must BUY THEM. Success in the market is the only way to get other manufacturers to resume 2-stroke development.

 

[john01]

I just hope if KTM goes that far they find the missing link too LOL. Then I may buy one.

 

[wallybean]

With the recession having hit KTM especially hard, I wonder if they are in a position to go forward with their DI on the schedule I had read before ~2012. I was under the impression that they were going to reduce new tooling for the immediate future.

Walt

 

[Motosportz]

Buddy of mine sent that to me a while back. Always telling me how great 2 strokes are. I ride the fence and like them both about equal. Its a good read but some stuff is a little over the top. 4st / 2st leapfrogging has been going on for decades. I think we will see 2strokes in favor again some time soon. Mainly driven by EFI and electronic ignition controls. The down side in the end they will become more complicated than current 4 strokes.

I have been reading for 10-15 years how these new tech direct injected 2 strokes like Orbital and others are developing were going to replace 4 stroke car engines and touted more efficiency, lighter weight and other advantages but has not happened despite lots of development time and effort.

I had the pleasure of spending 5 days on a Polaris Dragon EFI 800 sled, it was amazing. Then the last day it started to cut out and die, we popped the hood and stared at the motor while we scratched our heads. Seems most things in life are a trade off.

 

[Colo moto]

Very good read Tommie d. Thanks for posting.

 

[tommie d]

Maybe I'm wrong, but I think I read somewhere that TM or Beta was working on a DI two stroke. I've always been a two stroke fan when it comes to playing in the dirt so hopefully in the future we will see a two stroke Husky with FI of some sort.

 

[Motosportz]

I think it is TM your thinking of.

Leave it up to the massive inovators at Ossa to make the EFI 2stroke. Reverse and laid back cylinder as well. Also check the rad placement, right above the crank. 280i trials bike...

 

[tommie d]

The Ossa got a lot of press, it was all over the internet and in Trials News (now Trials & Enduro News) Great news paper by the way. Yes it was the TM I was thinking about but there was not much out there about it. I'll have too see if their is anymore news out on the TM yet.

 

[HuskyDude]

there is the Ski Doo 600 E-tec. So let's imagine that we wanted to build a killer enduro bike. One half of that Ski Doo motor would give us a 300-cc, single-cylinder motor with 60-hp. It would have lower exhaust emissions and lower fuel consumption than any four-stroke of equal performance. And, of course, it would still be a simple, compact, light, easy-to-maintain two-stroke. All the real engineering has already been done - it works, the parts are in production.

This is exciting we already know that Bombardier is no stranger to producing a killer bike which ran from 1973-1987. (I loved my Can am's)
Can you imagine if they went back into production with that engine.
I don't think it would take long before they were back on top again.

 

[Troy F Collins]

This is exciting we already know that Bombardier is no stranger to producing a killer bike which ran from 1973-1987. (I loved my Can am's)
Can you imagine if they went back into production with that engine.
I don't think it would take long before they were back on top again.

The bombardier 600 ETEC has to be seen to be believed....it will go a full season on one tank of oil....zero smoke...very low emissions....and thats in a sled...I think we are only just scratching the surface with this new technology


On the subject of OSSA......whats your take Dave....salivating yet ..???

 

[skid]

I've heard that the doo set up is considered too bulky to run on a dirtbike. I gotta believe if bombardier knew it would work on a bike it wowuld be licensed and out there in use right now

 

[HuskyDude]

On the subject of OSSA......whats your take Dave....salivating yet ..???

I'm kinda a Gaser Guy. But if someone was to give me a new OSSA.

I guess I could ride it for awhile.

Ya that sure is thinking out side the box. Once you look at it for a while, you got to wonder why they didn't do that in the first place.
And not

 

[Troy F Collins]

I've heard that the doo set up is considered too bulky to run on a dirtbike. I gotta believe if bombardier knew it would work on a bike it wowuld be licensed and out there in use right now

Yes...the cylinder heads have the injector modules coming right off the top...so there needs to be clearance for that...plus the ECU(fuel cooled !!)...also must have a very high pressure fuel pump 500psi..and battery less 55 volt 1200watt magneto

oil consumption is very very low....reason is no fuel passes through the crank case...so no oil gets washed off

I honestly think the real reason for not seeing ROTAX doing this for bikes is the manufactures havent been "squeezed enough yet"...perhaps one day


interesting to know they have it in the back pocket......

arent ROTAX and KTM...both austrian firms...hmmm

 

[Troy F Collins]

I'm kinda a Gaser Guy. But if someone was to give me a new OSSA.

I guess I could ride it for awhile.

Ya that sure is thinking out side the box. Once you look at it for a while, you got to wonder why they didn't do that in the first place.
And not

Its just too many close up shots... giving me a wettie


making me think of trying my hand at the finesse world of trials riding

On second thought..I have to cut down on buying machinery.....

 

[ray_ray]

I think it is TM your thinking of.

Leave it up to the massive inovators at Ossa to make the EFI 2stroke. Reverse and laid back cylinder as well. Also check the rad placement, right above the crank. 280i trials bike...

Ossa? Can you say competition? It takes out of the box thinking to invent something new!!! Thank god for the small hungry guy!

The article here is quite long to read also...below are some valid points it brings out on mixing our gas and oil. It also drives home the point that the best technology is not always gonna win out...Most if not all of the 'advanced' technology was born decades ago. We eat what is fed to us on a daily basis and the JAP companies are doing the feeding and look who is eating all this up? And according to this article, the JAP companies, who have the money to do the research, are the ones killing it. Who is bringing this advanced, back to the future technology, back to the bikes? Certainly not the ones who invented it years ago. Just be glad they did not get a patent on it or it would never see the light of day unless they wanted it to...

But this is nothing new with any of the white-collar companies of the world. Winchester did this with guns and rifles decades ago. IBM pretty much invented the computer and then let BillG sell them an OS he purchased (not invented) for the PC. He told them to license each OS for EACH computer. And if that was not enough, IBM let him help on the first OS2 graphical interface they wrote and then allowed him to walk out the door with their ideas in his head and he then 'invented windows' How pathetic is that but then IBM is doing well today. Take all this with a grain of salt... Want to know or predict the future, like the guy who wrote the article said, "How long you got to live"? LOL....

2-strokes aren't going any where..They have too much potential for sure Even today, with all the money spent on 4-strokes, they have only caught up...they are perceived to be ahead here in usa because of the JAP influence on the young ones ...

23rd May 2009
Phil Irving, who designed both two and four-stroke engines, calculated that at 4000 rpm, with a fuel/oil ratio of 20:1, said it "...works out to... one drop in about twenty revs." He also said that, "...if the engine is driven downhill for some distance with the throttle shut, especially if a low gear is engaged to provide more engine braking, little or no fuel passes through therefore no lubricant will be going in and some component, usually the big-end (connecting-rod bearing) may suffer in consequence."

When Yamaha first started getting serious horsepower from their racing engines, piston seizures were too common. So they did some tests to find out how much oil was enough. They found out - no surprise - that more power requires more oil. And they found a point beyond which 20:1 was not enough oil; a point they had been exceeding. They concluded that mixing the oil with the gas was not good enough. They then developed a pump system that metered the oil better in relation to power. Later, they were having big-end failures and they switched to a system that delivered the oil directly to the bearings. Really, they copied the system that Suzuki was already using. But Yamaha only used this method on their factory bikes. For the racers that they sold, they told the riders to mix the oil with the gas at 10:1 for break-in and 16:1 for racing.

This section is even more interesting...

1st June 2009:
I ran a 10:1 fuel/oil mix in a TZ250 Yamaha. It ran great. Of course, all the jets must be opened up. For a given jet size, more oil must mean less fuel; i.e., the air/fuel ratio goes lean. McCulloch Corporation - who made not only chainsaw and kart engines, but four and six-cylinder two-strokes for the military - also tested fuel/oil ratios. They found that the power output increased with the proportion of oil. It isn't just a matter of lubrication, reducing friction. Oil helps the rings to seal and provides a thermal bridge between parts that aids cooling.

Suzuki obviously understood all this. They used their 'posi-force' system on everything from a three-cylinder, 50-cc factory road racer to their production 400-cc motocrosser. Then they stopped. A kind of macho mentality took over the motocross world and oil-injection became effeminate. The oil pumps were replaced with a stencil on the gas tank telling riders to add oil to the gas at a ratio of 20:1. When I asked, I never found anyone who used that much oil. "Real men don't use oil!" Suzuki’s position seemed to be: "We can tell them the right thing to do, and if they don't do it, we can sell them a lot of spare parts." Actually, the manufacturers were deferring responsibility for the engines lubrication. "It's not our job!" So, 'the job' was given to people who didn't know what they were doing... the riders!

When just the right amount of oil - not too much or too little - is metered to all the parts that require lubrication, the amount of oil consumed is surprisingly small. The last Suzuki two-stroke road bike that I tested went 1700 miles on a quart to oil. That was a 550-cc triple, in late 1977. (1978 was the last model/year for Suzuki's big two-stroke road bikes.) Besides all the road miles, that bike survived a full dyno test and several all-out runs at the drag strip.

13th July 2009:
I have said that any modern (not traditional) two-stroke must have fuel-injection. I must now explain that 'fuel-injection' must have a different meaning for a two-stroke than for a four-stroke. Fuel-injection (FI) on a four-stroke is just an alternative to a carburetor. Both schemes meter a quantity of fuel in relation to some mass of air. Take a short ride on a four-stroke with a carb, then ride the same model with FI, and you might be hard pressed to tell the difference. Ride a two-stroke likewise, and you may not believe that the same basic engine is at work.

 

[rockdancer]

I know this has been discussed but just reading a mag article about a Western Australian company - Orbital that has been specilising in Direct Injection - they call it Air-assisted Direct Onjection.
Quoting from mag -
It uses an air blown fuel charge that produces extremely fine droplets eg a carby contains 500,000 droplets per 5mg of fuel charge - the ADI contains 25,000,000 . The effect this has on fuel burn and efficiency is drammatic.
The timing of the injection can be accurately controlled
The injection occurrs after the exhaust is closed . No unburnt fuel passes into the exhaust and this reduces emmissions.
Because of this timing of the fuel charge there is no need for the exhaust system to provide a percussive wave that gives the fuel charge sufficient residence time in the cylinder . This means no expansion chambers.
Dyno figures of comparisons between 2 and 4 stroke engines show the 2 stroke producing considerably more torque ( over double at low rpm ) and ofcourse more Hp

So better economy , more torque and power and low emissions !

(They have been working with Aprilia on scooters for a few years)

http://www.orbitalcorp.com.au/directinjection/technical.htm

 

[fran...k.]

I read that article linked in the first post perhaps a month ago when linked in another thread on here. Perhaps the idea is to discuss it here? I might make note the author starts comparing weights of a 105 cc two stroke with these specs I found on the web, 19 inch front wheel 16 inch rear and 43mm forks with another four stroke I think is a standard adult sized one. The article was intresting , I have envisioned his opposed twin idea however the comparison the author used makes one a little cautious about the rest of the stuff.

Now in my real world, I wanted a chain saw on the end of a pole and ended up with one which uses pre mix but operates on the four stroke principle. It really wasn't what I had in mind of getting, these things must sling more bar oil than burn pre mix oil in the two stroke principle.

Fran