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Message: [QUOTE="murf007, post: 1336432, member: 100344"] [b]part two[/b] 12th Jan 2009: He did not begin with the long-stroke CR250, but with half of Honda's NSR500V. This was a case-reed road-racing engine with a square bore-stroke ratio - like the McGrath generation YZ250s. Honda said that it made "135-plus horsepower" at 10,500 rpm; about 68-hp for a 250. If ten-five makes it sound like all the power was on the top end, one rider called it a "torque monster" and said the power was "similar to an open-class motocrosser". This engine was introduced at the first 500 GP, 1996. I have given these details because there has been, at least, the suggestion that the long-stroke 250 two-stroke had reached some sort of a technological limit (at less than 50-hp) and that the 450 four-stroke was some sort of a 'solution' to this 'problem'. In 2005, MotoVerde magazine (Spain) dyno tested the CRF450 and the RMZ450 and got 56-hp and 55.2-hp, respectively. So this was the basis of Ishibashis new "environmental conscious power unit". But he really only used the parameters; he built a new design. He got "AR Combustion" to work from about 3000 rpm to peak power - meaning that the engine could operate normally within that range without an ignition system! At the very bottom, the sparkplug initiated combustion and his "Pneumatic Direct Injection" limited HC and CO emissions. The engine made 60-hp at 11,000 rpm. Because the solenoid injector fed an anti-chamber - not the cylinder - its high-frequency limit did not restrict high-end power. In other words, Ishibashis approach did not require the invention of any new technology, only basic engineering. The technology required existed in the 1970s. There was a rumor that the NSR500V might be turned into a killer street bike. Of course, that never happened. Instead, Ishibashi was sent off to design Civic door latches, or whatever... -------------------------------------------------------------------------------- 27th Jan 2009: About now, someone should be asking: "If Honda knew how to make two-strokes that are cleaner and more economical than their four-strokes, that do not require any new technology, and that could win endurance races, why didn't they produce them?" Back in 1984, Steve Anderson (then Technical Editor of Cycle World Magazine) went to Japan for a VIP tour of Honda's (then) new racing R&D facility. There, Takeo Fukui, Design Director, "...made it clear that Honda views itself as a four-stroke company that will not be satisfied until it wins all of its championships with four-strokes." Simply put, the four-stroke engine has been company policy; in fact, it has been more of a religion. Anderson saw, "...shelf after shelf of oval pistons..." and was told that engines were running "...with at least eight valves per cylinder..." and turbo charging. We haven`t heard anything about oval pistons in a long time because, after spending umpteen millions of dollars, somebody saw that it was a really stupid idea. It was a way of getting around the racing rules. Four-strokes couldn't win within the rules, so Honda had to find some way to beat the two-strokes and/or the rules. The trouble was, no matter what the shape of the pistons, or how many valves they could stuff in, or how many rpm they could get out of them, the two-strokes kept getting faster and the four-strokes weren't even able to keep pace. In 1995, Mick Doohan was asked how much power his NSR500 two-stroke made: "I can`t tell you that, but I can tell you that if Honda produced a one-liter motor it would make upwards of 400 horsepower." It was about that time, it seems, when one of the four-stroke monks had an epiphany: "Instead of spending more money on exotic engines," he might have said, "which hasn't been getting us anywhere, why don't we just buy the AMA and FIM and make our own rules? For instance, we could require that all two-stroke riders wear their helmets backward - if they can't find the first turn, we have to win!" And that is - sort of -- what happened. Honda also likes to be seen as an "engineering company." I must point out that trying to force a particular technology (that is not working!) on a naive public (by denying options, rewriting race rules, etc.) is not any sort of 'engineering.' Jeremy McGrath defined the engineer's job: "I think the effort should be to build the best bike, period, no matter what it is." Thank you, Jeremy. -------------------------------------------------------------------------------- 10th Feb 2009: So, what is the 'best bike'? What does that mean - and who decides? Honda said, "No more two-strokes!" All over the world, riders dumped their two-strokes and rushed to buy four-strokes. Back in the 1950's, a few intellectuals, like J.K. Galbraith, issued a warning. As George F. Will put it: "...Americans are a bovine, manipulable herd - putty in the hands of advertisers who can manufacture demand for whatever products manufacturers want to produce." As L.J.K. Setright put it: "If a camel is a horse designed by a committee, then it is the job of the public-relations and advertising men to persuade the customers that the camel is really a horse after all, or that what they really wanted was a camel." Do you know what you want? For the manufacturers, the 'best bike' is the one that gets you to part with the most money. As E.F. Schumacher told us... in economics, the only measure of 'good' is profit. I tell people that in engineering, goodness is efficiency. The two are opposites: profit leads to more and more; efficiency to less and less. For you and me, 'best bike' must mean something else. What we are trying to do here is to give riders more information so that you can decide what the 'best bike' is for you. I don't want my fellow riders to get sucked-in the next time somebody says, "Da hump is a new feature, and next year we'll have a model with two humps!" If the manufacturers succeed by such deceptions, I too will end up riding a camel, because there won't be any more horses! I already know that the 'best bike' for me is the one not being made. What I will try to do in the next few segments is to look at this notion of the 'best bike' and point out how much the aim depends on you - the individual rider. I will also point to the dirt bikes available today and stress how limited our options are. Where I am going, in the long run, is in the direction of answering this question: If the two-stroke engine has a future in our field of interest, what sort of dirt bikes might we see and how might these new options bring you closer to your 'best bike'? I will begin by recommending a particular model, available now. I will put this in the form of a two-stroke/four-stroke comparison. I think the contrast is surprising. This bike could be an arrow pointing to much better dirt bikes in the future - if riders can get past their 'herd instincts'. The future of two strokes continues... -------------------------------------------------------------------------------- 23rd Feb 2009: The antagonist in my little play is Suzuki's RMZE 250. It says "Enduro Racing" on the swingarm. This is the motocrosser with minimum chassis changes to qualify as an "enduro" model. There is no electric starter or other non-essential to add weight. It weighs 229 lbs - less gas. It has five speeds and makes 33.4 hp @ 11.250 rpm. (All numbers in this comparison are from 'MotoVerde' magazine tests, not maker's claims.) The protagonist (drum roll, please) is the KTM 105 JMC. (I will explain the odd suffix.) This little 105-cc wonder rips 30.5 hp @ 12,000 rpm and has six speeds. But what makes it fly is that the all-up weight, less gas, is under 155 pounds! No, that is not a misprint; Suzy weighs 75 pounds more. Do this: Go out to the garage and find something that weighs about 75 lbs - a washing machine maybe. Pick it up. Do you really want to take that riding with you? Let me interrupt this for a brief trip through the Way-Back machine. In 1980, the AMA dropped the "claiming rule" and the factories gave their top riders unlimited "works" bikes. Dave Hawkins wrote then: "In motocross racing, it's obvious that power is important. But how much is enough?" In the 125 class: "The problem was not to make more power (30 bhp seemed quite enough for a 175-pound bike)... [and] only the best can fully use these bikes." Today, 30 years later, we still can't go into a dealer and buy a 175-pound bike with 30 hp. Instead, we are expected to dance with Miss Piggy from Hamatsu. What we can do is buy a 105 SX and bring it up to that old works-bike standard. And unless you are a better rider than the likes of Jeff Ward, Mark Barnett, and Broc Glover, that should be "quite enough". Let's get into the details. First, what is JMC? That is the establishment (in Spain) of Jess Balaguer. I cannot avoid calling him one of the top two-stroke tuners in the world. He has "the gift". He tweaked more than a 50% increase in horsepower from KTM's standard 105 SX. But that statement will make you think that it must be all top-end and could only make noise below ten-grand. In fact, the JMC is stronger everywhere. The smallest percentage increase is at 6000 rpm, where it still makes two ponies more than stock. And the stock motor is in no way peaky; it actually makes less peak power than the 85 SX. The 105 is more of an "enduro" motor. The JMC pulled the 'MotoVerde' dyno from 3000 rpm to 13,500 rpm. I cannot point to another engine that makes almost 300 hp/liter and has such a wide powerband. And while dynos can give one the wrong impression, the 'MotoVerde' crew said that the track tests confirmed "without a doubt" what the dyno promised. The bike rockets out of turns like...a works bike! What Are Your Thoughts On The Future Of Two Strokes? [/QUOTE]

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