Carburetor vs Fuel Injection - Why Motorcycle Riders Should Think Again

[Music] that is a hard question [Music] this is a carburetor but you don't see it because the fuel injector has replaced it as a better way to throw gas but is it because there's a subtle misconception and a simple lie that motorcyclists have bought into here and they both rolled in from the car world fundamentally when we hit the gas we're not actually adding fuel we're opening this throttle valve to allow more air passing wind would be a more accurate expression so try that next time you take your lady for a ride since we have our wind flowing in one direction there aren't so many random collisions of air particles meaning there isn't so much air pressure and all we have to do is offer a fuel source here and it'll get sucked down our intake tube because it has a higher flow and lower pressure than charlie sheen's left nostril you don't need an injector just physics so how much fuel do we want well 8 8 18 18 so 25 looks like one part for every 12 and a half parts air ish and that's a complete burn where all the fuel makes all the power and not just useless emissions trouble is sometimes your engine pumps slow sometimes fast how do we ensure it feeds the right amount of gas well first you need a fuel line and a floatie to plug it in this way our gasoline always starts at the same baseline so we can control its rate of delivery then we have one jet that's the perfect width to deliver fuel at idle speed as our throttle needle rises it gradually exposes the main jet it's roughly quarter trimmed at quarter throttle then half trimmed three-quarter trimmed but wide open the main jet is precisely the width of your cajones [Music] finally we need a way to manually choke the air supply and trim down the fuel mixture this is just for special cases like when the air is thin in colorado so you have to screw the idle fuel level down to match or when the fuel is cold on startup doesn't vaporize much so you have to bring the air supply down to match by pulling the choke knob and some people find it inconvenient to pull their knob once or twice a day but nine out of ten men don't mind a voila a purely mechanical route to nearly precise stoichiometry across a wide range of use people say carbs are simple once you understand them no they're just fricking not so we invented electronic fuel injection you dick around with your throttle just leave it to the engine sensors to measure how much air you let in so the engine's computer can tell this little guy how much fuel to squirt perfect simple and a complete lie and cars do real-time tailored fueling but motorcycles don't what actually happens is they run a prototype on a dyno fast slow hot cold to determine the ideal amount of fuel for each condition this information is charted onto a fuel map which is then loaded into every ecu that hits the showroom floor that means i need a throttle sensor to read my idiotic input a crankshaft sensor to read my rpm temperature sensor pressure sensor the bike takes all that information to its fuel map and says this is the closest condition we experimented with let's try that amount of fuel [Applause] it knows how to start without a choke it knows how to idle on a cold mountain pass but it's not perfect motorcycle manufacturers cannot and do not test for every condition so fuel maps have holes where you find snatchy throttles on a lot of modern motorcycles not to mention that no two machines are identical the prototype is a grand piano that has each string tuned but the fuel map your bike imports that's not tuning that's just hitting the piano with someone else's hammer and hoping it comes out sounding mostly right so both these things only provide nearly precise stoichiometry which is why under your butt you can't tell the difference between them but hold on fuel injected directly into the chamber leaves more room for air in the intake more air more boom should give more power and this spray of gas cools the chamber directly meaning we have a denser charge to compress higher compression ratio again there should be more power yes yes all true and good in cars motorcycles can't squeeze in direct injection because they rev so fast there isn't enough time for gas to spread out before it needs to fire again so motorcycle fuel injectors are all port injectors spraying into the same place as a carburetor same performance [Music] the great gains of fuel injection were always more relevant to cars motorcycles are just a drop in the ocean dragged along in the wake of a ship that already sailed there hasn't even been a carbureted car since 1990 the same year uncoincidentally that congress amended the clean air act to encourage the use of corn fuel and gasoline see ethanol gas separates into a gummy goo within weeks and the only reason that isn't a major sticking point is because all cars now run on high pressure injectors that cleared the gun meaning motorcycles with carburetors only recently became a pain in the ass if you forget this harley for a rainy four weeks like i did it won't start ethanol clogged jet requiring a full carb clean every four weeks so carburetors and fuel injectors both work a treat but injectors are the future because they allowed for a future fuel that made carburetors a thing of the past and that is a clever trick [Music] [Music] you

Channel: FortNine

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Id: ZRNfyz1Cgvg

Length: 7min 51sec (471 seconds)

Published: Sat Oct 30 2021