I took Big Boars post as him just saying that the development / tech level present in 4ts nowadays means that 2ts will be benefiting from much that has been learned from the 4t side of things - AND, that new 2ts when they come, will be a much better thing than they have been in part because of it.
We all know that 2ts HAVE to become cleaner than clean to continue to exist, because of the prejudice against them as being dirty , smelly, polluting things.
The wildy over-square development of 4ts is down to needing the revs to get higher HP levels, and the need for more flow, in and out of the head, to achieve that.
As 2ts inlet and exhaust comes through / out of the barrel, well , the stroke needs to be longer for the inlet and outlets - simplistically put, but accurate.
DFI will change this, to a certain extent, as the limit to fuel getting in is largely overcome, though you still need to get the air in - I think that to get the entire air/fuel charge in by just an injector unit itself would be extremely difficult - the injection system possibly would be bigger, more complicated than the engine itself - not that I am much of a motor man, my engineering experience and qualifications are more on the fabrication/chassis side of things, so I'd defer to others.
I've 2 good friends who are, respectively, a thermo dynamics specialist/engineer, and a EFI/DFI specialist / engineer. Our conversations with regards to 2t development are always interesting - neither are 2t devotees, but both, from their pure engineering points of view, believe that the 2t has a great future - moreso than 4ts, if only government/public prejudices are overcome, and manufacturers with a total commitment to 4ts can be "dealt' with - their words, not mine!
I doubt we will see such over-square dimensions on 2ts as 4ts, as they don't need it, but the DFI outboard motors are slightly over-square (ironically, I think some that I checked quite a while ago, pretty much echoed the over square dimensions of a CR500 - an engine that was quite an anomaly amongst big capacity 2ts).
Interestingly, the DFI 2ts , are using bigger capacity engines than the 4ts. I'd say it's a result of outboards being rated in HP, not capacity, and as the 2ts are so much lighter, they can go to bigger engines (yet Still be lighter!), for their under-stressed nature when delivering the HP level required, whilst giving all the benefits of more torque that the big engine delivers ( to add to the higher torque a 2t has, over a comparably sized and tuned [level of] 4t).
It will be interesting to see what happens with 2t tuning.
The rumours surrounding the Husaberg DFI 230 & 370 have them as having a straight pipe - no expansion chamber. This is the sort of thing I've discussed with my above mentioned friends. There may be a lot of different approaches to 2ts with the advent of 2ts - DFI can mean that the scavenging effect of a chamber will not be needed to 'reclaim' the lost fuel charge from the exhaust port, and the efficiency this gives negates the need for a chamber - ie: the 2t will not need to have such 'exotica' on it. A trapping valve exhaust port can add to this - combinations of these and AST and FAST tech means there will be potential for myriad combinations. My mates do also say that you'll still be able to get even more power with the use of a chamber, most notably when not using a trapping valve, as air/oxygen used to scavenge out the exhaust can be reclaimed to get it back into the engine. As both are also practicing academics, their maths escape me at times, as my math levels have decreased to that of just force vector analysis etc - if you don't use it, you loose it, is so very true.
Any way you look at it, Anybody who says 2t are at the end of their development is a fool. The variety of options that manufacturers/engineers have available to them is astounding. With respect to Mitch Payton, his assessment only applies to the old school 2ts which we currently are left with. And those comments were probably made a few years ago. Well do I remember many quotes attributed to Mitch, calling the YZF250 'cheater bikes' when he had only the 125 Kawi to do battle with it - mind you, he and his riders did damned well with it, and JS made the other riders look a bit silly the last year he rode the 2t (and , yes, I know he used a 4t for the last round at Glen Helen that year - after he'd wrapped up the title on one of the few 2ts still on track).
You can bet Honda will be lobbying even harder to keep 2ts from being given capacity equivalency - they are so committed to 4ts. Mind you, if it came to it, they still probably have more 2t engineering innovations locked up than anyone.......The EXP / ARC technology was probably just the tip of the iceberg.
