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tentativebike... |
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tentativebike... Renault 5 Driver
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Kentol750 |
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Kentol750 World Chat Champion
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andyscooter |
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Nobby the Bastard |
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Nobby the Bastard Harley Gaydar
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The Shaggy D.A. |
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The Shaggy D.A. Super Spammer
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P. Red Rocket
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talkToTheHat |
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Evil Hans |
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stinkwheel |
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stinkwheel Bovine Proctologist
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stinkwheel Bovine Proctologist
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Teflon-Mike |
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Teflon-Mike tl;dr
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Posted: 18:37 - 23 Nov 2017 Post subject: |
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Both Aprilia & Cagiva, with limited edition variants, built for Italian domestic Production-Racing, of the RS125 and the Mito, have accredited records or 101mph, to both claim to have made the 'fastest' standard production 125cc road bike....
I think that the Aprillia achieved a few tenths of an mph more than the Cagiva, but the Cagiva achieved its record over a full mile under American standards, the Aprila over a half Km to a Eropean standard.
But neither was ever 'restricted' to meet any artificial regulatory requirements; they were in fact 'factory-tuned' versions of usual catalog models, that seldom managed to achieve over 100mph from genuine customer representative over the counter models in independent tests.
The most powerful four-stroke, was 'possibly' the Peugot Jet-force scooter; though that was aided by a vane type super-charger.
But 'as standard' the boost dump valve was set to limit the engine to less than Euro-A1 compliant 15bhp; some specs claim as little as 8bhp, while variator gearing limited speed to around 70mph.
With the dump-valve clamped closed, suggested it might have been able to make up to about 20bhp, but the scooter styling/aerodynamics & the impediment of variator drive means that didn't result in any significant extra speed, and optimized to make use of the extra power, ie 'tuned' it might have achieve 'around' 85mph.
Also some controversy as to whether dealer 'de-restricted' Jet-Force compressor, was a genuine factory approved/endorsed variant, or not, let alone a 'standard production' model.
The most powerful 'standard production', and 'normally aspirated' 125 four-stroke, is the 1977 Honda CB125 Twin. Air-cooled, and with just two valves per cylinder, it claimed 17bhp, and just shy of 90mph... about 88, I think, in accredited two-way timed tests.
The later, 1981 CB125TD 'Super-Dream'was designed to be 'restricted' to 12.bhp and a tad over 70mph, for the then impending UK Learner-Laws. A full-power variant was offered, using the carbs and cam-shaft of the earlier 'Twin', was sold, I believe to special-order, in markets such as Italy, Switzerland and Southern Ireland, where power/speed restrictions weren't in force. The more common 'restricted' variant differentiated in Honda catalogs as the 'reduced effect' variant, the full-power CB125, is probably more legitimately the most powerful, and fastest 'standard production' 4-stroke 125 made.
The early Honda CBR125, was restricted beneath even Ero-A1 15bhp, to about 13bhp, in order to meet the power to weight limits, and had a claimed top speed of 70mph, same as the un-faired, 13bhp, 'reduced effect' CB125TD. Later variants, gained weight, that allowed it to be granted the full quota of 14.5bhp, and perhaps 5mph more top speed.
However, an HRC 'race kit' was offered, and possibly in Italy and maybe other markets like Australia, dealer fitted prior to sale, to homologate it as a 'production' model for domestic racing series.
The full HRC 'race kit' allowed its 4v water-cooled engine to make 17bhp, same as the street standard CB-Twin of 30 years earlier! And despite the fairing, a top sped no higher, of about 80mph!
Again, controversial whether the HRC kitted early CBR125 was or wasn't an actual 'production' model.
The Yamaha YZ-R125, was designed to meet Euro A1 limits, so has always offered 14.5bhp, and similarly, a top speed just shy of 80mph, despite many optimistic claims closer to 90.
Plenty of tuning kits are offered for the Yamaha Engine, also used in, I believe a Spanish built Derbi. I believe, an experimental build by a UK Magazine, managed to extract a maximum of 19bhp from one, without boring beyond 125cc; the cost of parts to achieve that was horrendous, ISTR about as much as the then brand new £4K bike! And warning was offered that the standard 15bhp engine was prone to eating its own internals if thrashed, so even with a pro-built engine, 'every-day-ride-able' reliability was not considered likely.
The Suzuki GSX-R125 is a relatively 'new' offering.. they claim it to be Euro-A1 complient, and to have as much sporting pedigree as they could give it... it has lower clip-ons than the YZF-R125..... and is cheaper..... other wise, I expect it to be no faster, and no more tune-able or reliable, and given other budget Suzuki levels of finish, probably not a lot less prone to 'flux' than a Honda CBF... but the jury has yet to be even convened, let alone to adjourn long enough to come to a verdict, on that one.
SO! The 'fastest' standard production 125, that is 'restricted' to Euro-A1 licence regulations, is pretty much any of them! The 'restrictions' are designed so that none can really be any faster than any other IF restricted!!!
Without restriction; the Aprillia RS and Cagba Mito, both hold 'production bike' speed records a nadge over 100mph, for a 125cc displacement machine. Though most over the counter examples wouldn't crack the magic ton, certainly not under standardized two-way test conditons over a measured mile or more, whatever the optimistic and MPH remarked speedo may say!
Fastest 'Production' 125, running on pump octane fuel, I believe was an over-the-couter Honda RS125 GP bike, put through the traps at Bonneville a decade or so ago. With some-where between 40 & 45bhp, (& crank life measured i running minutes!!!) I think it clocked the traps with a two-way time somewhere a little short of 140mph... so if you take restrictions out of the equation, that's about the best that might be achieved, without building a full stream-liner... if you dont mind replacing most of the engine almost as often as you refill the petrol tank.
Offering useful comparison of 'fast'; the 500cc four-stroke Kawasaki ER5, considered by so many to be as dull as ditch-water, and utterly unexciting and far from fast.. offers a claimed 50bhp, and 120mph top speed.
Which begs suggestion that in the greater scheme of things, pretty much all 125's are actually pretty slow, even the fastest of the fast un-restricted offerings, and were it not for artificial licence, taxation or race class regulations, there would be absolutely no incentive to try and make a higher performance 125, when its cheaper and easier just to make a bigger engine, and all 125's would be cheaper, limited performance 'utility' machines as so many of the genre actually are.
Morral? If you want 'fast' buy a bigger bike. If you want 'cheap' buy a bigger bike. And only 17-19 year olds, have any real reason to grumble, impedimented by age and licence regulations from either option.
Interesting fact; the 1981 Honda CB250RS, a four-stroke single, that sold as a 'budget' commuter when new, offers approximately 29bhp, and 95mph top speed, without the aid of a fairing. It is as powerful and as fast as most of the fastest of the fast two-stroke 125's, but almost forty years old, and never considered a high-performance machine; and there are literally hundreds of similar more utilitarian 130-400cc motorcycles, of that or more contemporary vintage that offer similar levels of performance, that are cheaper and usually more reliable than 125 offerings, and as much or more performance as anything in the Learner-Legal displacement class.
Util 3DL licence regulations came into force in 2013, the 'learner restrictions' were entirely self imposed by dint of NOT bothering to get a full-licence.... now, 17-19 year olds are lumbered with them regardless, but same still true for any-one else.
Question "Whats the fastest 125" is the bad penny that keeps coming back around, but really, it should be "Whats the least slow 125" because in a world of bikes where you can get pretty much as much fast as you can want, and machines with 200mph super-car 'fast' performance available over the counter, still for family hatch-back car sort of money, and old hyper-bikes like the 170+mph Kawasaki ZZR1100, available for as little money as a 'cheap' 125.... NONE of them are really even close to being 'fast'!! ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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owl |
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owl World Chat Champion
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Rogerborg |
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Rogerborg nimbA
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Commuter_Tim |
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Commuter_Tim World Chat Champion
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Teflon-Mike |
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Teflon-Mike tl;dr
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trevor saxe-coburg-gotha |
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trevor saxe-coburg-gotha World Chat Champion
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Old Thread Alert!
The last post was made 6 years, 152 days ago. Instead of replying here, would creating a new thread be more useful? |
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