Engine evolution?

[slofox]

Hope I am not covering old ground here....
Back in the early-mid 70's, I dabbled a little in racing. In those days, the 2 stroke bikes reigned supreme. Nowadays the 2 stroke race bike is largely a thing of the past. I am interested in the why's and wherefore's of this change in engine technology. I have searched in vain for explanatory articles. Anybody out there who can help with info or reference articles?
Ta in advance.

[James Deuce]

Emissions and fuel consumption.

Well, actually the perception that non-visible emissions are better than visible ones somehow.

Greens! Can't live with them.....

Pass the beer nuts.

[Wally Simmonds]

Out of sight, out of mind etc.

[Jantar]

Hope I am not covering old ground here....
Back in the early-mid 70's, I dabbled a little in racing. In those days, the 2 stroke bikes reigned supreme. Nowadays the 2 stroke race bike is largely a thing of the past. I am interested in the why's and wherefore's of this change in engine technology. I have searched in vain for explanatory articles. Anybody out there who can help with info or reference articles?
Ta in advance.

Various countries have set emission standards that either directly or indirectly outlaw large capacity road legal 2 strokes. It has little to do with engine technology, more with green perceptions.

[tri boy]

My 2cents, four strokes also took a leap in design technology via WSB racing, and to a certain extent two strokes had damn near stalled out in development potential. It would be awsome to have an up to date two stroke GP bike slug it out against the 4strokes, but I think maybe modern 4strokes would win.
MHO
Was the Q related to racing or general bikes?
Oh, welcome to the site. Don't listen to the rest of the inmates, I'm always right.........

[James Deuce]

Out of sight, out of mind etc.

Greens have minds?

Maybe I will have to vote for them.

[FJRider]

Greens have minds?

Maybe I will have to vote for them.

They're in good condition, they change it frequently.

[Mental Trousers]

As tri boy said, 2 strokes had pretty much stalled development wise. The only real advance in 2 strokes has been the move to direct injection recently. However, it's incredibly difficult to get direct injection right (the Bimota V-Due is a great example) and it's too late now as everyone see's 2 strokes as being old technology and very dirty. I think in we may see 2 strokes dominate in racing again, but that's likely to be a long way off and I don't know if 2 strokes will ever really overcome the advantage the 4 strokes have in grip.

[James Deuce]

Orbital direct injection for two strokes is working perfectly right now and powering all sorts of ROVs. They are cleaner than their four stroke or rotary counterparts and produce twice the torque for a given capacity when compared to a four stroke.

A 1000cc two stroke using Orbital's technology combined with modern electronic rider aids wouldn't have any drama making diesel's-tall-headed-unnecessarily-endowed-with-far-too-many-valves look like the slugs they are.

Grip was always down to tyre development. The modern MotoGP bikes benefited tremendously from all the tyre and suspension development done by their two stroke predecessors.

Two strokes are banned because Greens are idiots. A 500cc two stroke diesel Toyota Yaris would make a Prius look like a gas guzzling pig (which they are, but lets not go there because "Greeness" is measured by a perception index, not fact or reality).

[yod]

Emissions and fuel consumption.

Well, actually the perception that non-visible emissions are better than visible ones somehow.

Greens! Can't live with them.....

Pass the beer nuts.

ah nice one Norm....

[Mental Trousers]

Two strokes are banned because Greens are idiots. A 500cc two stroke diesel Toyota Yaris would make a Prius look like a gas guzzling pig (which they are, but lets not go there because "Greeness" is measured by a perception index, not fact or reality).

Can't argue with that.

Direct Injection is definitely way more reliable and usable now. But it's too late. Now it's going into things like Scooters and outboards, but not bikes. None of the manufacturers can see a market for 2 strokes bikes at the moment. Blame the Greenies and all the misconceptions and misinformation around.

[TimeOut]

It would be awsome to have an up to date two stroke GP bike slug it out against the 4strokes, but I think maybe modern 4strokes would win.

Not if two strokes were allowed the same size engine.

[CB ARGH]

Everybodie's painted their asses green and want to be environmental dicks; two strokes are like ten cigars. In other words... I have no idea.

[FJRider]

I think the main reasons for change from 2 stroke to 4. Was for similar reasons Formular one changed their engines from V 10's to V8's. Reduce costs to build and slow the buggers DOWN. (make them SAFER)

[Subike]

I think the main reasons for change from 2 stroke to 4. Was for similar reasons Formular one changed their engines from V 10's to V8's. Reduce costs to build and slow the buggers DOWN. (make them SAFER)

the real reason........ safty. agree