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SmokinJoe439
10/26/2018 1:21pm
10/26/2018 1:21pm
Edited Date/Time
10/27/2018 1:51am
I found this pic of a HRC engine I'm sure it was a later model 250 v-twin GP bike. Was it ever used in racing not sure. Is that a pneumatic operated power valve?
55hp fuel injected 400cc two-stroke. Honda raced Dakar and Baja with it in '95.
The Shop
They tested heavily! But solving the EFI issues - to this day - hasn't really happened.
I think honda's "smart" 2t guys were gone by mid 90s (with all their hard work accomplished far earlier. Be it retirement - or better opportunities or even transition to 4t side of honda - but their later stuff had a few flaws that was worse in areas than the previous generation (with improvements on "paper" - that could have panned out)
That dakar engine was ultra trick - to this day would be cool in the 2t world.
Even though the 1994 season saw no major changes, towards the end a water injection system was incorporated to the exhausts which improved performance in the mid-range of revolutions. An extra 10 hp were achieved in the range between 6000 and 10 000 rpm when the temperature of the combustion chambers was modified. Doohan decided against this improvement and instead chose a more conventional engine, since the bike was already sufficiently hard to handle. Doohan finally managed to win the World Championship on this machine, making it evident that the NSR500 development was reaching its peak.
In 1995, carburettors over 39 mm were installed, significantly improving performance. Thanks to this tweak, and a stronger than ever Honda team, Doohan won his first two World Championships for the Repsol Honda Team in 1995 and 1996.
https://www.boxrepsol.com/en/technology/the-honda-nsr500-engine-evolution/
Riding Mick Doohan's Honda NSR500
Doohan, etc, apparently, didn't. Most Top Level Riders are rather conservative - they want what they've won on before, plus a few percent. Though, Doohan played 'games' with his rivals, when it came to bike / engine usage. The FI 'd 500 was, apparently, quite a savage beast, and it reputedly, sent a fair few riders 'sky high' with even more vicious high sides than was the 'norm' in those days. Doohan might have been on the wrong end of one of those, during testing.
Honda has probably more 2t tech locked away in their archives than all the other manufacturers combined. But, it's locked away, never to see daylight. More or less 'design exercises' that they got through letting their engineers flex their 'muscles' with. And, they probably still are doing 2t research, today. They did make use of some of the aspects of the EXP2 - the Activated Radicals / Trapping Valve side of it, with the CRM250AR. The 400cc 2t EXP had about 12 - 15HP less than the Works V Twin 780cc 4ts, the same Torque, and weighed about 100lbs less, reputedly. And, used less fuel.
But, Honda is : "All Fourstroke, All The Time". Well they always were until the 70s Dirt Bike Boom came along, and they wanted a slice of the action, with their (rogue engineers) 'lawnmower project'. And their NR500 Oval Piston, 8 valves per cylinder , with twin conrods per piston bike was a racing failure when they returned to the Road Race GPs. Though, they learned a hell of a lot from it. They then turned to 2 strokes, to win, until they got rules to their suiting.
I'd written this before Underground put his article copies up, but hadn't posted it. So I got 'Itoh' right. My neighbours came in with some beers before my trip to Singapore tomorrow, and I downed a few. I'm going over for a mates Wedding, and he's got perfect timing, as I'm doing the 1 hour flight up to KL Airport next Sunday, for the Sepang MotoGP. The tracks about 1.5ks away from KL Airport. Flights and ticket for the race ad up to less than $200, so it would be silly not to go!
I remember 'cause I put one on my... CR 500 rear fender.
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