Hey honda, Its Year 2001! Wake up! Hondas OHC XR50 engine was first used in there 1962 50cc scooter. Back in the 60's that OHC engine was state of the art, but its still used today Its time to build something thats actually up to date. Lets see, for your waverunner I would take a 1500cc 4 cylinder engine and add some of the indy car tech to it such as EFI, V-tech, and maybe the cool new camless design that uses fuel injector type cylionids insted of cams and poppet valves so the thing can actually rev past 15,000RPM! Alright, time to build a new sport quad engine... Hmm, lets take a 650cc design and build it so it makes more power than a normal 700cc engine with half the weight by useing EFI with MAP sensor, V-tech, 6 valves per cylinder, Oval pistions,2 cylinder liquid cooled DOHC design. This would make some serious low end troque with its V-tech and EFI and also rev past 12,000RPM with its 6 valves and oval pistion design Also throw in a 6 speed trans with reverse and use cannondales design where the intake is in the front and exahust exits the rear to limit bends in the system. Just a late night thought, lets here more ideas on this subject

 

JRM, your excellent and thoughtful post, filled with creative initiatives and possibilites, somehow produces an image in my mind:

Under swaying palms on the clean sandy beach of a tropical island, an altitude-challenged (as in, short) man, dressed in a white linen suit and wearing a black string tie, points skyward, exclaiming, "Look, Boss! Da plane! Da plane!"

While I cannot account for the image, I salute your catalog of engine innovations. Less exotically, Honda might consider desmodromic valves to achieve higher rpms, don't you think?

Thanks for your interesting post.

Diogenes

 

Honda might consider desmodromic valves to achieve higher rpms, don't you think

While the Desmo valves seemed to work OK in the Triumph TR2 and Ferguson tractor, I'd rather see a design based on the Coates spherical rotary valve - since we're already on fantasy island...

 

Here we go............

 

im 100% not famuliar with the "desmodromic" valve, but have read about the rotery valve, but I seen a demo indy engine at the local track that had electric cylinoyed (misspelled) vavles that were run by the computer, thus elemationg the entire heavy valve train! just think- the computer can alter the valve timming anytime it needs to to adjust for conditions. the engine i seen as 3,000cc 12 cylinder engine that reved past 20,000RPM

 

Honda doesn't make waverunners, you silly guy. Even if they did, 4 cylinders on a waverunner is too big! Waverunners are supposed to be small. Yamha has a 1200cc 155HP triple cylinder engine and that flies. If Honda did make waverunners, though, I agree with you on a feul injection system instead of three carbuerators. Carbs are too much maintenance, but then again, wouldn't a feul injection get all messed up if it floods, or water somehow seeps through (especially salt water)?

 

actually honda will soon. Here is a link:
http://www.hondamotorcycle.com/model...Watercraft.htm
And EFI, when built right is less likley to have problems than carbs when abused, drowned, ect. I have sank a 88' Toyota 22RE to the roof in the surf and after being pulled out and the aircleaner dryed it fired right up with minimual roughness a injector is the size of a spark plug and the computer is the size of a computer mouse tops- all is needed is a tiny fuel pump and your all set to never have to worry about choke, altitude, temp, idle speed again EFI is much less foof than carbs- just pop the hood on a 1988-1994 chev truck and you would be amazed at how much room there is compaired to the carb models of the 80's.

 

back to the original post... why should honda waste time building a 4 stroke? Whats so great about them? They are heavy, rev slow, extremely loud and soud like crap (literally!) are the biggest painn in the @ss to workon, respond little to mods.... so now is the time to build a decent 2 stroke, like what Bombardier is working on. A 250 rotax engine with 50 hp stock, wow it would take about a 500cc 4 stroke to top those numbers. I know people think 2 strokes will never see much more production, but their is a hell of a lot more demand for a simple, powerful, light, easy to work on/maintain engine rather than its opposite counterpart.

 

Are you forgetting the principal of if it works don't break it?

The laws of physics have not changed in the last 30 years - at least not that we know of. Combustion is still combustion. Engines still run on the same principal. Those old engines have years of expirence behind them.

Sure Honda could make an engine that can achive 20,000 rpm. Engineers have achived 125,000 rpms in the lab (Tesla turbins) Don't forget the downside: reliability. Honda has earned a reputation for bullet proff engines. Nobody is surprized to see a 15 year old Honda still running. High rpms are the enemy of long life engines.

EFI has nothing to do with building a new engine. However it isn't compatable with kick/pull start which you want in many models of quads. Still, it coulld/should be retrofitted to their big quads where electric start is the game. Accually not EFI but rather direct injection, but whatever.

2 strokes have some advantages. They tend to lose many of them when you try to make them better though. weight is the biggest advantage, enviroment and efficacy is the biggest disadvantage. I wish bombadire luck in their 2 stroke devolpment, but I suspect they know that they have little time to perfect it before enviromental concerns ban it outright. (Strange things about these bans, is once they are in effect even if you proved your new 2-stroke was better then a 4 stroke could get in theory it is still banned)

 

Is everybody forgetting that Arctic Cat puts EFI on their sleds? And it's batteryless?
You pull the rope once to charge the system, pull it twice to start it. It starts on 2 pulls every time.
Why can't this technology be applied to the off-road world??
One more thing: 2 strokes are on the way out. One reason Yamaha built the Raptor is so when the retrictions get too tight(and someday they will) and they are forced to discontinue the Banshee they will already have a hi-performance quad on the market. Wake up and get real!