Kevin is a wealth of motorcycle knowledge. I'm sure many others and I could listen to him for hours.

Brings back found memories of reading Kevin's articles in Cycle World every month. Thank you Gentlemen.

Technical writer here. Kevin is one of my long-time heroes.

I could watch you guys all day. Especially Kevin giving us the intimate details of how a flame travels around the top of a piston. I mean who else would know so much about Norton engines? Keep it up. 👍

ENJOYED YOUR COMMENTS ON THE NORTON COMMANDO HEADS. This why TC Chistenson on On our Top Fuel Norton HogSlayer beat all the Harleys , Triumphs and Hondas in the 70s. Basically the equivalent of Combat engines that we made first. The Atlas ports were terrible. Mike Berliner had me bring one of our heads to show Jack Williams at Norton UK. Jack said this was probably what the designer had in mind. We convinced Norton Owner Dennis Poore to mass produce the Commando ports as such. The 1963 Atlas had spigoted barrels. I built several with 3" bore and 12 to 1 CR. flat top pistons to the top of the spigot. Roll on was spectacular, but it ran out of steam above 6K because of the small valves. We showed Norton and they made the 828cc 850 with low compression and stock 750 valves. They and Dunstall had big valve race heads. John Gregory Norton HogSlayer Race Team.

One of my favorite kludges was with a Ford 4-cylinder engine called the "Split Port" design. They were aware that swirl and/or tumble made more torque and that increasing the speed of the airflow in the intake runner could improve cylinder filling. On the other hand, they didn't want to redesign the engine or use valve deactivation, so they put a butterfly valve in front of one of the two intake valves that would block its flow at low revs to create higher velocity in the other and a horizontal swirl in the cylinder for increased torque for the lower and mid-range. At higher revs, the butterfly valve would open and the flow from both intake valves would create a decent tumble. It was not optimal, but made me smile.

Guys these podcasts are great. It would be great if you upload the audio to other podcast apps? Try to avoid having KZfaq app on my phone since it’s a distraction but would love to listen to this on Spotify or the Apple podcast app on rides/in the car. I’ve found even though you miss out on maybe some photos or graphics this kind of content transfers over quite well to audio only format.

Way back in 1982, Yamaha spent a bunch of money and time on researching why engines waste fuel. The bottom line was to produce an engine with pistons that were flat as possible and a cylinder head that was only slightly domed with three intake valves and two exhausts and minimal reliefs for the valves in the top of the piston. This became the Genesis engine with 121HP out of 750cc. With the carbs wide open it was a straight shot down from the throttles into the combustion chamber. I was amazed at it then and I still am.

I rode Parilla small singles in racing in the early '60s and it had more, across the board power, than motors from other countries. Italy produced some mighty engines in that period that were sturdy and "fun" . H-D Aermacchi, Parilla, Ducati, and Motobi were top four-stroke ligtweights of the era, easy to maintain and powerful. All had Hemi combustion chambers and lots of spark advance at high revs. Two strokes were just beginning to come into their own with Bultaco and Husqvarna. Won many races on a 200cc Parilla against the two-stroke comers like CZ.

Back in the 70's I had a 427 Chevy with a dual port Offenhauser manifold. They split the intake port into two separate runners each connected to a separate venturi of the 4 barrel carburetor. This was done to increase port velocity at low RPM but still have good flow for high RPM.

My favorite engine was in my 18' GSX-S1000F.

I have 2 Nortons. I have toured all over Western North America and much of Europe on an 850 and I love the way it pulls - including with 2 up and camping gear. Thanks, Kevin, now I understand (a bit) why.

Thanks for these podcasts. I live on the Canadian Prairies where we get 5 to 7 months of riding weather and 5 to 7 months of no riding weather. It's the no riding weather that gets me into trouble. In the summer I'm too busy enjoying riding to give any time to content about progress in the marketplace. The winter provides the marketing team the opportunity to convince me I must have the next wizbang. Your podcast is the antidote. It's much more fascinating than any video extolling the virtue of the addition of a seventh ride mode. For my own selfish reasons, I wish you the best of success.

11:35❤ I just love this guy and always enjoyed his writings... No valves! Everything up to this point has remained true in the realm of my two-stroke..😮 and I love that. I have never altered its ignition timing from what was set at the manufacturing facility in Japan, the little CR 125 seems perfectly timed from idle through the roof @11000 ... I jet it, fat low into quarter throttle and leaning towards a 🥵 radiator testing top BRAA-AAAAP! Kevin is 🤯 genius ⚙️ head

Always learn lots when Kevin shares his knowledge! Great podcast, and hope to hear many more from you fellas!

Have any of the motorcycle makers fiddled with using the valves to throttle the engines? IIRC one of the European automotive manufacturers fiddled with this in the 1950's or 1960's, but there were just too many tiny parts that required precise adjustment and activation. Part of the idea was to get sonic flow through the valves to improve mixture of fuel into the air. It also reduced pumping losses at part-throttle by shutting the intake valves early, effectively increasing expansion ratio.

Love this channel. Keep it coming. Future topic could be engine balance, primary/secondary forces, crank designs

Great discussion , i love the high torque at 1200 feeling . Looking forward to the oil discussion , hard to find 50 weight oil , non synthetic , for my classic AJS single , here in British Columbia .

It sounded like you guys should have written the ads back in the 70s, But the Norton Girl was hard to beat and very easy on the eyes.

The best. Thanks again.

40:00 Very interesting to hear Kevin talk about small intake ports and high charge velocity. I think I have some people refer to this phenomena as, inertial supercharging.

I've had all kinds of motorcycles over the years ; but my favorite is my iron head Sportster 😇

I have always loved the '90s, inline fours like the FJ 1200, ZZR 1200, & Triumph Trophy 1200's. Great combination of top end HP & great mid range torque. I believe these utilized the Cosworth flow head design.

KTM 1390 test ride ?? got to be sweet..power

great content--- VVT cam ?? makes great stuff... more low mid torqe and shiftd then too high rpms .. concours 14 started mitsabishi motor..flat cyrve from @2k up/ concours 14 Varible valve timing from mitsabishi ? torq low mid from that zx 14 motor

one note, on the kickstart bikes, that lever he's talking about is a decompression lever in my experience. exhaust cam has a little ball that pokes down to bleed some pressure off while you're kicking it. he could be right I just never heard of a timing lever

Explain how fuel quality has improved allowing for so many more possibilities and how the compression ceiling has pretty much disappeared in the modern era

The problem with a flatter head, low dome is a larger flow angle for the intake and exhaust ports, reducing flow in and out of the combustion chamber. Coming from my experience with four valve automotive engines, BMW M-50 vs Honda FC-20C. I built the BMW with everything to build horsepower as quickly as possible but was never able to get it to match the stock 2.0 liter horsepower. The Honda just has better flow because of the steeper valve angle, built better power with v-tech and steeper flow.

Very interesting. I didn't know about a Cosworth book. Looking at Mr Duckworth, that DFV/DFX was the most successful F1 engine that became the most successful Indy engine. I'm still touring on a GS1000G because I don't know what I would like better. Parts are becoming a problem.

It was mentioned that the gas tank on bikes has been replaced by an air box. What are the advantages of an airbox? Would the surrounding air not act as a huge air box? or does size matter here? Also, is there a rough, over the thumb rule, at what rpm the engine should be turned by the starter and what torque is needed perhap in relation to output torque as a percentage figure?

The crazy thing is that the Norton Commando has relatively slow port speed. The 750s and early 850s had faster port speed than the late 850s. However, there are ways to convert the late ports to the early ports and even to convert to modern style ports. Dont get me wrong the commando is flawed in other ways, but there is something amazing about that engine, and to a certain extent what Triumph and BSA did in the 60s that is lost on a lot of modern motorcycles.

Could listen to these guys for hours. Even if they didn't talk about the "Low End Torque" that my SV650 makes which causes me to smile. LOL

Good conversation. I look forward to the most anecdotal topic on social media in your next video, aka, Black Gold, Texas Tea :)

Great video

Please do a pod on the tuned mass damper in motoGP

Reminds me of emissions, a lot of modern engineering is meant to provide "happy" engines but with the additional considerations of meeting emissions as well. Diesel for example, is now ladened with emission considerations to the point of accepting longevity compromises... any comment on how emissions effects the happiness of a motorcycle engine? I hear Yamaha will discontinue the R1 in face of those nee EU regs...

Liked and subscribed instantly.

Let's talk about how tires have evolved and how tire technology went in the wrong direction just like the combustion chamber designs and technology went backwards in both fields

Man says you need turbulence to mix fuel well but also that attached flow makes it 15% better. You can't have an attached turbulent flow by definition.

An inline 4 made by Kawasaki … Let the good times Roll!

May you guys do these videos together forever 😉

Do you remember the old 2-stroke trick of leaving a ring of carbon just around the circumference of the piston, to help with the squish band?

To get an engine down to idle speed the ignition has to be retarded further than generating peak pressure just after top dead centre. Retarding timing also reduces peak cylinder pressure since the cylinder volume has increased by the time the burn occurs. An Alpha GTV6 has idle timing at 5 degrees after TDC.

Only one?? 😩 Depends your fancy that day... Inline 4 - Top end rush Inline Twin - punchy fun power V Twins and Thumpers - gobs of torque

25:00 😂 There is Samsonite luggage with two feet of pipes. Making up the air box of my 1200 GSA... Under a plastic cover, atop a large fuel tank... That weirdo machine has a sweet engine that has taken me on and off roads...😢 And I do miss my HD Dyna... cuz it was😎 loud and torquey💨

Let's talk about how Japan refused to abandon the dome piston while playing with four valves for so many years

Why doesn' the Goldwing require Trim Tabs like a boat? Longitudinal Axis 100 Ft. Lbs has to cause issues.

Bottom TQ? Nah, I love the Hill Hold feature on my '24 Street Glide..

Free revving, good midrange, top end pop.

Explain detonation and where and how it develops when the whole fuel air mixer isn't burned explain why a cool running head fights against that engine knock

Are you going to tackle the oil monster? How about going after the brake in methods arguments next time?

We cant wait to see Ducati Power in F1 Kevin and I

KH Harleys have a smaller intake valve than their Indian counterparts! Handshift cheaters use KH intake profiles in their barrels on Scout motors! Kevin Cameron is a national treasure! And he lives near me! Well almost, lol!

Kevin!!!

Cars or motorcycles, most people "think" they want HP but what they really want is TORQUE . This is the full 6 standard deviations of the market. Yes, a very few can use and want peak HP numbers, but this is rare. How well would a Honda RC149 work on the street....haha. (ps Please do not use the word "Vacuum". No such thng, just pressure differentials. )

Have any motorcycles taken advantage of direct Injection? How about VVT? The HP they can get without either makes it irrelevant, but still. Yamaha indicates no need for more than Lash caps and fixed timing roller cams.

Norton commando ring sealing mid stroke ..

Now I know why research scientist are talking to ICE cylinder head design engineers in an effort get faster fusion of hydrogen isotopes with less energy. Swirl is one of the things that does that within the microseconds that it takes to fuse hydrogen into helium.

Do this again explain more why the flat top piston and the tumble go together explain more about timing and what people are looking for and what it does for power explain how duckworth didn't tell anyone about turbulence for over 10 years because he was making sure Ford 1 races explain how Ducati figure out the trouble first a motorcycle

Let's talk about the relationship between Bell helicopters and MV Augustus

Great Engine? Depends on application. So I will speak from the standpoint of the average rider on the street. ease of service, mid range, power, tunability for more power, and sound. Every engine that the routine service is easily performed on, repaired with available parts, has loads of mid range power, sounds awesome, and we can tune it to get 15 to 30% more power out of it . That's a great engine! we riders don't give a dang about timing, top dead center, burn rate, that's for builders and mechanic to worry about.

How about an episode on v fours ?

What makes a great m/c engine is no secret yet, it's over your head !!

Please make Kevin exclusive content channel podcast!... I am begging (directly from brazil)

We are here for Kevin ... IYKWIM

I have a honda 450 that runs off the bottom so well you would sweat it is faster than my smr... but it isn't. My S1000 makes over 70 ft lbs from 4000 to 14000 and it really does not feel that fast.... I guess it's not a commando... lol

.027" squish - unheard of!!! .045" or .040" if you feel lucky!!!

Directed injected 2-stroke running on hydrogen, methanol or natural gas❤

That was well worth subscribing for... I have become fascinated by transmissions... My little dirt bike has six speeds and needs every year for work to be done... My V-Twin 😂had 'three gears and two ranges' The touring adventure bike from Germany.. has a four-speed box with two overdrives on top.. I've made a living driving semis and anything from 10 speed to 18 speed gearboxes... For moving big weight 😜 makes moving my own ass and some 🪄 relying on gear selection in the world, fast becoming ⚙️ automated

One if by land , two if by sea , three if by internet . Btw , the 5 valve crap , has toooo much intake turbulence .

Air cooled boxers 😊

You didn't even talk about the Moto guzzi V8 motor

What makes a great motorcycle engine? That's an easy question to answer. Liquid cooled V4 with a desmo valve train wrapped in RED.))))

Watching this video is hard for me to take seriously when I see the person wearing the black hat with cycle world on the hat I’m having flashbacks of Wayne’s World 😂😂😂🎉🎉🎉to funny

38:00😂 2$troke🪄 smell it

That old pump gas must have been cut with peanutbutter.

Bull..........speed of combustion is highly variable because it's pressure dependant, and cylinder pressure is highly variable during combustion. Take some propellent out of a cartridge and see how slowly it burn at atmospheric pressure, compared to shooting hte cartridge in a gun.

And most of all explain why his book classic motorcycle racing is still so expensive and they won't print more of them god dammit

More bull..........maximum piston velocity is not at 90 deg crank angle, but occurs when the long axis of the conrod is tangential to the circle swept by the center of the crank pin. You guys need to sharpen up your game !!!

If i was building a motorcycle from parts i would relosten to wtf he just said 😑 😅

They are not secrets they are engineering designs by really smart people.

There's guys don't have a life 😞 some people will post anything.

anything not made by the wierdness of Honda.

The Yamaha R1 crossplane is the best engine ever made in my opinion

Reliability. Harley has CONSTANTLY played catch up with that and it almost cost them more than once. The British trumped America after WW2, and the Japanese trumped THEM ALL especially after Vietnam.