When Yamaha Almost Went Crazy 

Approaching the bike with feeler gauges in hand and you hear a booming voice: "BE NOT AFRAID"

be not afraid…

got dammit you beat me to it

​@@Oddman1980🤣🤣

​@@Oddman1980Just don't mix the valve shims up😂

worked in Japan have you? I laugh-spit my beer out when I read that.... well done.

It's OK to be scared Scared.. Yamaha is going to be back in front. 😊

I always found it interesting how they built a DOHC head for a Ford OHV block.

@@skylinefever there are a bunch of pretty impressive cars that Yamaha made heads for. The Toyota LFA is another..

Vw 1.8t 20v is also yamaha design. 🎉

Well they dropped 5 valve long ago even in today's Moto GP prototypes. Ducati is better known for getting the most power from a set capacity in recent racing.

Yamaha (and cosworth, we won't forget about them) have proven being the past and current greatest

Don't care what others think.

honda was simply smarter than yamaha and realized more valves per cylinder only works if you change the shape of the cylinder, yamaha was stubborn and stuck with a round shape and wasted their time, now they use 4 valve again

@@bluestripes1. Yeah ? So how Reliable were the NR series Engines ? Answer is : They WEREN'T . So , you were saying ? Honda DID have a good idea , but the Engineering Problems and Hurdles were always going to be a " Huge Ask " and proved insurmountable in the end . Yamaha DO still use 5 valve configuration , and sell it to others as well .

@@bluestripes1 As the OP stated , the Honda NR series was just a 4 valve per cylinder V8 with pairs of siamesed cylinders - designed to get around the 4 cylinder limit imposed at the time. It wasn't really an innovation. If it was , there would have been be more than just a token production model.

Imagine the drag on the systems that forced all those valve springs open. Of course, each spring would have less resistance due to smaller valves, but still.

@@exothermal.sprocket . Exactly . Any Volumetric Gains were Lost again with the added resistance and complexity .

Loved my FZR1000! My favorite engine in all of motorcycling. Yamaha really hit the mark with a great design as the valve adjustment intervals were at 26,000 miles. I put close to 100,000 miles on that bike and only made one valve adjustment. These were hard miles too as this bike was a Sunday morning jailhouse special. When I sold her she was still running strong, not smoking or leaking. Wish I had her back.

im am deeply sorry for you

My cat loves u too.. free India from RSS!

4 valves allow a central spark plug, the main reason its so popular

WHAT ! ? Both 4 and 5 valve designs ARE crossflow . Basically by definition . In fact Crossflow has be USUAL since the demise of Side-valve Heads .

@@johncunningham4820 jeez u sound fun at parties mate,😂😂😂 ok I lemme correct myself. it be cool to see a 5 valve engine, with triflux inspired valve layout on the cylinder head. Happy now Karen 👍🏼

@@_Y.J . So then , clearly YOU don't take well to being called out on speaking Total Fucking Rubbish . 5 valve head designs only JUST justify themselves in volumetric efficiency vs mechanical loss over 4 valve designs by a small margin . Sufficient to be worthwhile . Diesel Engine (heavy-duty types ) also tried 5 & 6 valve designs and ran into the Same Issues as Petrol/Gasoline Engines . Too much valve shrouding . Making 90% of the Combustion Chamber into Valve area actually didn't help , and the Mechanical losses DRIVING all that extra complexity , and hence , reduced reliability and increased maintenance , was actually to ZERO net gains .

@@johncunningham4820 mate read the top comment u mong, I never said anything to do with gains, quit whining with ya long paragraphs that no one cares for, take that stick out ya backside and go outside for the first time, u clearly been stuck in ya shed for 50+ years, I never said anything about gains so clearly u can't read 😂😂😂

4 valves is just the magic number for a round combustion chamber, it provides the biggest gas flow without making the valve train overcomplicated. Specialty designed exhaust improves gas scavenging and intake compressor shoves more air into the engine, so that efficiently solves both issues that large number of valves were meant to solve. The whole reason anyone even went the route of making more valves over just using a turbo is the arbitrary racing rules and restrictions that they had to work around.

Recent new design have proven 5 valve gives greastest power and torgue combined with a state of the art combustion chamber designed by Patric Miller Engeneering

Sadly they've recently said that they'll exit the snowmobile business.

@@Guovssohas I know eh, very disappointing.

Rotary valve would eliminate the design problems with poppet valve systems, but there's a few challenges to overcome with those too.

There are 5 Valve GDI engines, but their sparkplugs are offset and not great for road use.

@@SlowSTEN Oh, okay.

I was a Micron dealer in the mid 90's. Nicely made pipes but heavy.

@@mikerieck306 They were pretty common, not sure what caused that company to stop producing. I liked their rainbow colored heat treatments. Mainly, they were a simple oval or round shape at varying lengths and the tone they produced was very complimentary to inline-4 cylinders. Today exhausts cost a LOT more, offer less reduction of loudness, offer a much worse tone, and have far more expensive and complicated materials and shapes.

Yes, the A/B testing

That is a Yamaha designed Head on that . They design Heads for a Shit-Ton of other people .

@@johncunningham4820 yes I'm aware of the Yamaha Toyota joint ventures. Yamaha are about harmonics and sound....as per the LFA 👌

I've got one of each luckily enough

@@jameshatton4405 I was just trying to Educate , in the event you Didn't know . Not belittle you . Actually , Harmonics yes , but FLOW DYNAMICS is the other thing . A Crisp sound is a byproduct of That . Also LFA is a V-10 . They ALL sound awesome anyway .

@@ChroniclesofKToyoda . One each What ?

Err no not quite , the 5 valve head was better at the time but eventually materials / development caught up and allowed a four valve design to match the 5 valve head .

@@Dwainpipe21 Not sure what materials development altered physics, but gas flow through a poppet valve is tied closer to total periphery than area.... until the valves crowd each other and the periphery effects clash. The breathing advantage of a 5-valve was always marginal, if it existed, and the cost (in every meaning) was high. Maybe worth if from the marketing side, but when that petered out, goner.

@@ElsinoreRacer I read when they went back to 4 valve design it was because 5 valves allow more revs better control of the valves as the valves are lighter ( smaller ) but with modern materials a 4 valve head is just as good .

There are many more engines developed by Yamaha

@@VisioRacer yup Volvo & Ford are also among those that come to mind, but yeah, Donut Media did a video on how they started from a group of Toyota's Engineers who were responsible for racing & engine development. I'm glad I have a few of their engines including a couple 5 Valvers, wish they'd kept them going

Also some model of porsche i heard..

I did not realize Yamaha was involved in the RB26DETT.

@@skylinefever Albrecht Goertz of Yamaha is responsible for his working with Nissan, even though the official partnership with Nissan feel thru his designs are still reflected in the L series, RB series & the Nissan Fairlady which all stem from the 2000GT project which originally was meant for Nissan Ironically Nissan thought it not financially viable so Goertz took the project to conservative Toyota & we got Japan's first supercar the Toyota 2000GT, but if you look up Nissan 2000GT you will find what resembles a Corvette Stingray front with a Fairlady Z body Under it's hood was the R&D that led to the L series which if you know is what evolved to the RB, though the RB is closer to the original Yamaha R&D. The story was supposedly that Nissan didn't need the partnership, but if you look at what came of it Nissan clearly reused the Yamaha derived work The difference is, it's Nissan take on Yamaha R&D that was developed for them but doesn't credit, which in Japan is legal, it's how the Yamaha derived Toyota 2ZZ basically has iVTEC before Honda when Honda only had VTEC before Toyota's VVTLi, they both took each other's ideas TLDR; reason most don't know Yamaha's designs lead to the RB is because within Japan you can take others ideas so long as you add your own twist or pay royalties a few years. Yamaha for example doesn't get to gatekeep who uses their research(even though in this case it was for Nissan), it's part of why Japan has a leg up on innovation, because they have to constantly innovate something new to stay relevant against their own R&D, it's also why they can't sue Nissan, just like how litigious Nintendo can't go against PalWorld since their IP is both Japan based

Welcome time traveller!

@@fidelcatsro6948 oh man when I say your comment it would be like panic attack🥴🥴🥴🥴🥴🥴🥴

@@custommodspresentation5338 please go back to 1970 and buy a genuine German VW beetle for me for 3000 dollars and bring it back to 2024..

@@custommodspresentation5338 im from 1896 myself😆

@@fidelcatsro6948 man what can i say I want to jump from forth floor twice😇😇😇😇😇😰

Marvin the Martian’s spaceship had rack and pinion molecules!

Give yourself a break. It is oblong, but nobody knows this term.

A diesel doesn't even need the rotary valves, you can just not have an exhaust or inlet manifold. Packard made a diesel radial like that, the DR-980. There was also a rotary (spinning radial engine, not the dorito type rotary) called the gnome monosoupape that worked a similar way, but being a spark ignition engine it needed a secondary set of inlet ports at the bottom of the cylinder to get fuel in.

Yeah, everything has optimum number, more or less will useless..

Mostly due to not having wrist pin oil squirter!

Low velocity is good. It means lower pressure loss through the port.

Yes