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.
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 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. 👍
Have a couple of desmodromic powered Ducati Monsters and understand what Kevin was referring to as " difficult to work on". Purchased a Desert Sled in 2020 and while setting the valves was surprised to find all dimensions half size compared to the Monsters. Putting in the keeper wires under the shims on the exhaust of the forward cylinder wasn't working. Shop tweezers were too big, too. The Wife was watching the air turn blue and retreated. She came back in a few minutes and said "try these"- they worked perfectly. I asked where they came from - "eyebrow tweezers" says She. The Sled's tool kit is complete.
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.
Subaru does something similar in some of its engines with butterfly valves in the intakes to create turbulence in the airflow to help with proper mixture formation and therefore combustion. Honda's CVCC engines worked on a parallel idea using a rich mixture from a different portion of the carb to ensure easy ignitability and generate turbulence in the main portion of the combustion chamber that had a lean mixture. The small amount of rich mixture burning would ignite the lean mixture and impart turbulence to increase the speed it would burn at.
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.
Guys these podcasts are great. It would be great if you upload the audio to other podcast apps? Try to avoid having RUclips 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.
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.
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.
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
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.
@@johncrowley5612 Thanks. I knew they had been fiddling with variable intake valves for at least 60 years, but did not realize they finally started using them in production engines. Me, I'm too cheap to look at BMW's.😁
@@stevedavies4953 An interesting distinction is that the 1950's system was largely aimed at better fuel volatilization at part throttle as opposed to just controlling air intake. The carbs and fuel injection systems of the time generated larger fuel droplets. The system I remember attempted to use small intake valve lift to create sonic flow conditions between the valve and valve-seat to achieve better atomization and fuel/air mixing at part throttle. It was mechanically complicated and IIRC, could never maintain even filling across cylinders.
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.
Midday from NZ . My Farther and his mate rode overland from UK in 1961 on a 1955 Triumph Thunderbird with a sidecar . I still have the machine with me . At 56 years of age I know how not to ruin a nice old original used machine . Always nice to tune into your shows 😊 All the best from over here in Kiwi land 😀
Talking about cold starts, I always loved cold starting TZ250's with no choke and no idle setting. Push until it pops and don't move the throttle. Lovely memories
Can't tell you how much I appreciate Cycle World's m/c tech analysis from these old masters of the subject, one thing always puzzles me is the power stoke interchange of energy between the crank and piston/rod assembly as the piston starts from rest and accelerates down, doing work accelerating the crank then at some point the crank starts doing work on the piston to deaccelerate it unto rest...but at the same time the cylinder pressure is trying to accelerate the piston ...so it the engine still generating power as the piston slows down ? and if it is not, why not open the exhaust valve soon as the piston starts to reverse its acceleration as the crank has to do work to oppose cylinder pressure ?
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 .
My twin cam 103 harley with .570 lift cams is set at 31 degrees. Early close on the valves. 98.7 h.p. and 116 ftlbs of tourque. Most of the tourque in by 2,000 rpm with good manners. It really breathes up high too. 75,000 miles and top end has never been off the bike. Stock valve springs too. It might drop a valve tomorrow but man what a ride.
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 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.
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.
Absolutely fantastic,really enjoyed your chat about a subject that i love. how's about the history of the twin cam engine goes back a long way.! just a thought 😁 Great job guy's.
I never knew Kevin was telepathic ! He said Exactly what she said Last Night ! TWICE Times Small IS Still Small ! ! Thanks Swami Ken ! I bought her a magnifying glass ! ! .l..... Nick , NavyBlueSmoke , LST-1195 .........
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
67 Sportster ran great. Cam surface stated coming off and blew the forked rod. Standard rebuild PB+ cams. The distributor had really light springs and one was broken for a long time chewing up the inside. New HD springs were heavier. Engine won't get out of it's own way like there is no advance. Tired to find lighter springs but they don't exist. Might need to cannibalize a couple ball point pens.
Riveting stuff. There's so much more to bikes than 0 to 60 and (academic?) top speed! Twenty years ago, in France, I came across "Moto Téchnologie" and bought copies I have since kept. It did credit to bikes' extraordinary sophistication. I do hope the mag is still published.
I’ve had quite a few motorcycles but my favourites were my 2 Norton commandos a mk2 roadster and a mk3 interstate if they had a decent electric start id still have my mk3.hi from New Zealand 🇳🇿 😊
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
You actually had two levers, one pulled around like what the choke lever was on the other side, next to the throttle, the other was more of a trigger lever you pulled for decompression. The timing lever was typically fit to the left side handlebar. I rode many '50s single 500cc bikes that had both and one needed to respect the protocol to keep from being hurt on the kick start leg. Reason was, those bikes had magneto ignition with no auto-advance feature; it required you to do it manually. Big Harley '74s of back in the day used a twist grip to do the same purpose, to retard the ignition for starting. You didn't want to disregard that on the mighty Harleys.
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💨
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.
Coswoth in the 80s had a race boat with its engine in, think it was ON class against the outboard engines (2strokes) in the UK it had a mercruiser drive rebuilt by Cosworth and was successful and very fast.Took it too USA who banned it immediately, for obvious reasons.
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?
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
To me a great motorcycle and a great motorcycle engine are all about smart shrewd use of materials and designs that are balanced in every way. That's how you get the best bikes for the money. We tend to forget the best bikes are made for the road not the track.
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.
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...
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
Two things that kill all japanese 4 stroke dirt bike racers of MX life is cut short due to the valve spring and the hivo cam chain that most of the time ends up hanging out the bottom of the engine case
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!
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.
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.
Interesting article but too much emphasis on combustion efficiency and flow. Never mentions power to weight ratio, vibration, sound, reliability and several other characteristics that contribute to great engines. That Norton that may have great intake design was actually a poorly designed bottom end with crankshaft flex that needed bearing redesign in the early 1970s and the need for isolastic mounts to combat vibration. BTW did you ever study sleeve valve engines for ideal combustion chamber shapes. I suspect Kevin has with his mention of WW-II aircraft engines.
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
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.
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. )
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
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.
Had to laugh when he said the guys build it and the engineers tell you why it works.trade guy myself .i think most tradesmen have had similar experiences!😊😅😊😂
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
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
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
Kevin is a wealth of motorcycle knowledge. I'm sure many others and I could listen to him for hours.
Many of us felt the same with his writing 40/50 years ago
Technical writer here. Kevin is one of my long-time heroes.
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.
Brings back found memories of reading Kevin's articles in Cycle World every month. Thank you Gentlemen.
Once I discovered Kevin, I searched for his columns.
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 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. 👍
Have a couple of desmodromic powered Ducati Monsters and understand what Kevin was referring to as " difficult to work on". Purchased a Desert Sled in 2020 and while setting the valves was surprised to find all dimensions half size compared to the Monsters. Putting in the keeper wires under the shims on the exhaust of the forward cylinder wasn't working. Shop tweezers were too big, too. The Wife was watching the air turn blue and retreated. She came back in a few minutes and said "try these"- they worked perfectly. I asked where they came from - "eyebrow tweezers" says She. The Sled's tool kit is complete.
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.
Subaru does something similar in some of its engines with butterfly valves in the intakes to create turbulence in the airflow to help with proper mixture formation and therefore combustion.
Honda's CVCC engines worked on a parallel idea using a rich mixture from a different portion of the carb to ensure easy ignitability and generate turbulence in the main portion of the combustion chamber that had a lean mixture. The small amount of rich mixture burning would ignite the lean mixture and impart turbulence to increase the speed it would burn at.
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.
Guys these podcasts are great. It would be great if you upload the audio to other podcast apps? Try to avoid having RUclips 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.
It's on Spotify. I just watch it here with the quality at 144p and pretend it's 1997 again.
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.
My favorite engine was in my 18' GSX-S1000F.
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.
Kevin's deep knowledge is a treasure. These podcasts need to be archived permanently. Never, ever boring either.
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.
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
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.
BMW currently use "Valvetronic" on some car engines where the motion of the inlet valves controls the flow thus eliminating the throttle.
@@johncrowley5612 Thanks. I knew they had been fiddling with variable intake valves for at least 60 years, but did not realize they finally started using them in production engines. Me, I'm too cheap to look at BMW's.😁
The Fiat Multiair and Freevalve also do this.
@@stevedavies4953 An interesting distinction is that the 1950's system was largely aimed at better fuel volatilization at part throttle as opposed to just controlling air intake. The carbs and fuel injection systems of the time generated larger fuel droplets. The system I remember attempted to use small intake valve lift to create sonic flow conditions between the valve and valve-seat to achieve better atomization and fuel/air mixing at part throttle. It was mechanically complicated and IIRC, could never maintain even filling across cylinders.
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.
Midday from NZ . My Farther and his mate rode overland from UK in 1961 on a 1955 Triumph Thunderbird with a sidecar . I still have the machine with me . At 56 years of age I know how not to ruin a nice old original used machine . Always nice to tune into your shows 😊 All the best from over here in Kiwi land 😀
Talking about cold starts, I always loved cold starting TZ250's with no choke and no idle setting. Push until it pops and don't move the throttle. Lovely memories
Best RUclips channel ever, could listen to Kevin for years
Can't tell you how much I appreciate Cycle World's m/c tech analysis from these old masters of the subject, one thing always puzzles me is the power stoke interchange of energy between the crank and piston/rod assembly as the piston starts from rest and accelerates down, doing work accelerating the crank then at some point the crank starts doing work on the piston to deaccelerate it unto rest...but at the same time the cylinder pressure is trying to accelerate the piston ...so it the engine still generating power as the piston slows down ? and if it is not, why not open the exhaust valve soon as the piston starts to reverse its acceleration as the crank has to do work to oppose cylinder pressure ?
Always learn lots when Kevin shares his knowledge! Great podcast, and hope to hear many more from you fellas!
BTW, in your pantheon of sweet engines, just as you described, throw in the Suzuki L twin from the SV650. Happiest motor I've known.
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 .
My twin cam 103 harley with .570 lift cams is set at 31 degrees. Early close on the valves. 98.7 h.p. and 116 ftlbs of tourque. Most of the tourque in by 2,000 rpm with good manners. It really breathes up high too. 75,000 miles and top end has never been off the bike. Stock valve springs too. It might drop a valve tomorrow but man what a ride.
I'm really enjoying these podcasts, and learning so much!
KTM 1390 test ride ?? got to be sweet..power
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.
Poor man's supercharger
Only one?? 😩 Depends your fancy that day...
Inline 4 - Top end rush
Inline Twin - punchy fun power
V Twins and Thumpers - gobs of torque
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.
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.
Absolutely fantastic,really enjoyed your chat about a subject that i love. how's about the history of the twin cam engine goes back a long way.! just a thought 😁 Great job guy's.
I never knew Kevin was telepathic ! He said Exactly what she said Last Night ! TWICE Times Small IS Still Small ! ! Thanks Swami Ken ! I bought her a magnifying glass ! ! .l..... Nick , NavyBlueSmoke , LST-1195 .........
I've had all kinds of motorcycles over the years ; but my favorite is my iron head Sportster 😇
Great example of what NOT to do…
@@macmclemore 🤣 and no front brakes
Love this channel. Keep it coming. Future topic could be engine balance, primary/secondary forces, crank designs
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
Think I'll be listening to this one more than once.
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
An inline 4 made by Kawasaki … Let the good times Roll!
concours 14 Varible valve timing from mitsabishi ? torq low mid from that zx 14 motor
67 Sportster ran great. Cam surface stated coming off and blew the forked rod. Standard rebuild PB+ cams. The distributor had really light springs and one was broken for a long time chewing up the inside. New HD springs were heavier. Engine won't get out of it's own way like there is no advance. Tired to find lighter springs but they don't exist. Might need to cannibalize a couple ball point pens.
The best. Thanks again.
Riveting stuff. There's so much more to bikes than 0 to 60 and (academic?) top speed! Twenty years ago, in France, I came across "Moto Téchnologie" and bought copies I have since kept. It did credit to bikes' extraordinary sophistication. I do hope the mag is still published.
I’ve had quite a few motorcycles but my favourites were my 2 Norton commandos a mk2 roadster and a mk3 interstate if they had a decent electric start id still have my mk3.hi from New Zealand 🇳🇿 😊
DAVID VISARD
Now there's a real motorsport hero .
No BS and gives respect where it's due . Top Man 👨
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
You actually had two levers, one pulled around like what the choke lever was on the other side, next to the throttle, the other was more of a trigger lever you pulled for decompression. The timing lever was typically fit to the left side handlebar. I rode many '50s single 500cc bikes that had both and one needed to respect the protocol to keep from being hurt on the kick start leg. Reason was, those bikes had magneto ignition with no auto-advance feature; it required you to do it manually. Big Harley '74s of back in the day used a twist grip to do the same purpose, to retard the ignition for starting. You didn't want to disregard that on the mighty Harleys.
Great video
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💨
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.
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Coswoth in the 80s had a race boat with its engine in, think it was ON class against the outboard engines (2strokes) in the UK it had a mercruiser drive rebuilt by Cosworth and was successful and very fast.Took it too USA who banned it immediately, for obvious reasons.
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?
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
To me a great motorcycle and a great motorcycle engine are all about smart shrewd use of materials and designs that are balanced in every way. That's how you get the best bikes for the money. We tend to forget the best bikes are made for the road not the track.
Hemi heads do well with a high dome piston, because the spark plug is in the center of the chamber.
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.
You don’t speak for all riders. I am a rider who is very interested in how my engine works.
@@LTVoyager 👌
Good conversation. I look forward to the most anecdotal topic on social media in your next video, aka, Black Gold, Texas Tea :)
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...
We cant wait to see Ducati Power in F1 Kevin and I
Please do a pod on the tuned mass damper in motoGP
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?
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
Free revving, good midrange, top end pop.
What makes a great m/c engine is no secret yet, it's over your head !!
Two things that kill all japanese 4 stroke dirt bike racers of MX life is cut short due to the valve spring and the hivo cam chain that most of the time ends up hanging out the bottom of the engine case
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!
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.
Great advice
That old pump gas must have been cut with peanutbutter.
They said there was 4ozs of lead in a full tank of gas. Maybe 20 gals or so.
I think I timed my RD350 at 10 BTDC.
Many ring changes and cyl rebuilds
Edit: God I wish I could still have that bike.
Are you going to tackle the oil monster? How about going after the brake in methods arguments next time?
Kevin!!!
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.
Bottom TQ? Nah, I love the Hill Hold feature on my '24 Street Glide..
Interesting article but too much emphasis on combustion efficiency and flow. Never mentions power to weight ratio, vibration, sound, reliability and several other characteristics that contribute to great engines. That Norton that may have great intake design was actually a poorly designed bottom end with crankshaft flex that needed bearing redesign in the early 1970s and the need for isolastic mounts to combat vibration. BTW did you ever study sleeve valve engines for ideal combustion chamber shapes. I suspect Kevin has with his mention of WW-II aircraft engines.
Let's talk about how Japan refused to abandon the dome piston while playing with four valves for so many years
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
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.
Why doesn' the Goldwing require Trim Tabs like a boat? Longitudinal Axis 100 Ft. Lbs has to cause issues.
Let's talk about the relationship between Bell helicopters and MV Augustus
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. )
We are here for Kevin ... IYKWIM
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
How about an episode on v fours ?
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.
Peak velocity of the piston is at ~76°, not 90.
Had to laugh when he said the guys build it and the engineers tell you why it works.trade guy myself .i think most tradesmen have had similar experiences!😊😅😊😂
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
Amazing
Directed injected 2-stroke running on hydrogen, methanol or natural gas❤
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
Please make Kevin exclusive content channel podcast!... I am begging (directly from brazil)
Norton commando ring sealing mid stroke ..
L twin is good for street.
.027" squish - unheard of!!! .045" or .040" if you feel lucky!!!
Two-stroke tuners work down to that especiaĺly on smaller capacity engines, the lower limit is set by piston clearance and detonation.
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
Doing a hard launch on a well set up Commando is like a rocket sled ride.
I think GSX-R 1000 K5/6 has best engine. No matter what gear or revs, always deliver.
Air cooled boxers 😊