I am 68 years old and grew up reading the American magazines. I learned so much from Gordon Jennings and Kevin as they explained so much more than just putting parts together. With a lot personality thrown in I might add. I have been very fortunate to have been involved in our sport during this time. Thanks to you Mark for your contribution as well. I do miss paper mags though. Good stuff guys, really enjoy these.
As one of the people currently developing the KTM for flat track I can tell you you're absolutely correct. Modifying the crank pistons, head and cam are costly. Way over 10K for. But who really cares about that. Its exciting to develop another motor and see what it can become
One of my favorite bikes, as an original 1978 CX500 owner I watched the development progress to this fantastic conclusion. Another great episode! Thanks
CX500 one more very cool Japanese models no one asked for man there were so many others how about the Yamaha 550 Vision? One year wonder....really interesting even apealing but not any great reason to go buy one....building stuff no one asked for....a big file folder
I think the vision is related to the Venture, therefore the Vmax, also. I remember in the Venture Royale test in 83, either Cycle, Cycle World, or Cycle Guide called it a "double vision", implying that the venture was based on the vision. Probably not, they were likely designed at the same time, but I don't know. I think they were a 2 year bike..one year with diaphragm butterfly valve carbs, the other with more typical CV carbs. I think they're good looking The cx650s sure run better than the 500s, which were just dogs..a cx650custom (short wheelbase) does pretty good wheelies. Then you smash your shins on the valve covers....ouch! Former Honda/yamaha mechanic from the 80s/90s, so got to ride them. You probably know the CX's are pushrod, cam in block motors, with 4 valves per cyl. Combustion chamber centerline is twisted relative to the crank. Weird, but pretty good
I started competitively racing pull start minibikes 3 years ago, one of the fast guys told me last year “you wanna be fast? Get your compression ratio up around 12.5 to 13:1” I’ll be about 12.5-12.7 with this new 236cc engine I’m building for next season. But on the other hand you don’t want tooooo much compression on a single cylinder, for longevity at least. It doesn’t have a companion cylinder to help push it back up. That’s what I have read at least.
Some of the best motorcycle racing I’ve ever seen were the Daytona Stadium flat trackers. They are the sprintcars of the two wheeled racing world. As much as I loved the XR’s, the cahoots of the Motor Company and the AMA screwed innovation in the name of preservation of tradition. On the suspension discussion, I was a stock car guy. Once I got the concept of “suspension doesn’t hold the vehicle up it holds the tires down and complying with the surfaces of the track” my chassis and suspension setups and success improved immensely! As always excellent content!
The AMA killed flat track racing long ago. If it wasn’t for the AMA you could go into your local Honda, Yamaha, Suzuki or Kawasaki dealer and buy an almost race ready flat tracker just as you can buy a MX or Enduro bike now.
That's laughable and for the life of me I couldn't even begin to imagine the logic process that comes up with that. The AMA doesn't tell motorcycle manufacturers what they can sell and what they can't, and if manufacturers don't have a factory flat track racing program, or if they have one and pull the plug on it like Honda did with theirs in the 80's, that's on them. The Japanese motorcycle manufacturers put their money into Superbike racing programs because that's what sells their motorcycles, everyone who's into Japanese motorcycles don't go anywhere near flat track races, so why would the Japanese manufacturers dump millions into a flat track racing program? There's no payoff for it. And what killed flat track popularity in the US was motorcross and supercross, that was a sport where some kid whose dad had a little bit of money could get a dirt bike and hit a local track to see if he had what it takes, hardly nobody's dad has the kind of money to get them into flat track, but 45+ years ago if your dad bought you an Elsinore you could go racing. What really made teenage kids in America hot to race motorcross was in 1980 when Marty Moates beat all the best European riders in the US Grand Prix, before that every year everyone watched the best riders in the world come over from Europe and take an American trophy home with them, but then in 1980 an underdog privateer beat all of them and overnight every kid in America dreamed about being the next Marty Moates and motorcross exploded in popularity and the stands at flat track racing drained.
@@dukecraig2402 There were a lot of Armatures racing Motocross from 1970 to 1980 also. Every weekend they had 100 CC 125 CC 175 CC 250 CC and Open classes. 125-A 125-B and 125-C classes ect. Motocross was way more popular in the amateur ranks back then than it is now. When a New Race bike cost $600.00 or a bit more new. People went to the races with an old Van a pickup or a car with a 3 place open trailer behind it. You didn't have to be all that good to be competitive compared to now days where you need to go to racing schools and have coaches and a practice Track ect.
@mikeskidmore6754 I know, I was a teenager back then, I did say that European riders came over to America didn't I? And didn't I give a time frame of "45+" years and mention the Honda Elsinore both of which puts that part of my comment solidly in the 1970's? So obviously motorcross racing was going on here and yes I knew about it at the time, my point is it really exploded after Moates won the US Grand Prix and is what really shifted popularity away from flat track racing and into motorcross. A good example is in the 1976 movie The Bad News Bears, the scene where Kelly Leak is in the dance studio trying to pick up that woman that looks like she's 30 (which is hysterical and I still laugh at it, "You like motorcycles? I got a Harley."), if you look at his Tshirt it has a "Flat Tracker" iron-on on the front of it, 5 years later it'd have been a motorcross iron-on because kids didn't want to go to flat track races anymore, they wanted their dads to take them to motocross races even if they weren't racing themselves, their heroes shifted from flat track racers to dirt bike racers, that more than anything else is what killed the popularity of flat track, not anything the AMA did, not all this conspiracy nonsense everyone's always throwing around about the AMA supposedly inventing rules to favor Harley, that's all nothing but people popping off who don't know anything about flat track or its history, a perfect example is everyone always saying that the AMA limited OHV engines to 500cc in the 60's to keep the British bikes from beating Harley, that rule was enacted in 1932 when there was over 130 motorcycle manufacturers in the US and long before anyone brought a bike from overseas to race on county fair dirt horse racing tracks. It's amazing the people who know nothing about the sport, have never even been to a flat track race in their life but they talk about it like they're an expert on the subject, it's the single most misunderstood form of motorcycle racing there is because people aren't into like years ago but oh boy, when it comes time to talk about it they're instant experts.
Flat tracking is great. As a kid it was the first motorcycle race I ever saw. Wanted a better view, worked up to the fence, peered over and got a face full of dirt. It was great.
So interesting to hear about Gene Romero's role in development of the RS750. I saw him race many times, great to learn that his expertise was valued as a contributor to that project.
So good to hear you guys talk about Jeff Haney. That guy is an absolute legend, i always wonder what his carreer would have looked like, if a big team took him in. His results on the CX and NS, damaged his carreer, but those results sure as hell were not to blame on Jeff’s talent for riding.
I was lucky to attend the San Jose Mile on several occasions. Being there and watching the riders move around at speed on the bikes combined with the smells and sounds was glorious. TV watching is great, but a live flat track race belongs on ones bucket list.
It was either 1982 or 83 I was at the Springfield mile and had an infield pass courtesy of a Honda dealer. Honda showed up with 3 bikes, 2 were modified CX liquid cooled and 1 was the new aircooled purpose built racer. Mike Kidd and Terry Poovie were on the liquid cooled bikes and Hank Scott was on the race bike. Harley had a factory team of 5 or more riders, Jay Springsteen being one of them and my personal favorite. In the end, after a rain delay, Hank Scott won on the new Honda race bike and leather clad Harley riders in the grandstand were anything but happy. Needless to say, if the AMA wanted to keep their primary fan base buying tickets and new HDs they had to slow down the competition (Honda).
In support of the farmer analogy, I'll draw attention to Carroll Shelby, former chicken farmer. Shelby's cars were kept simple, sometimes to the point of being crude, but they did get the hay into the barn reliably.
This was the fake cooling fin era. I really liked the Honda VT 500 flat track. The offset crankpin and shaft drive. There may have been something about not going any narrower because of intake interferance like H-D 45 degree. I think it was the smallest bike with shaft drive in Canada. Honda also sold the FT500. The Chevy/Ilmor V8 was interesting for having quite short pushrods. They raised the camshaft in the block and had porcupine pushrods. Apparentley Kieth Duckworth was working on a two stroke boxer with a university before he passed away - maybe something to do with generation in developing countries. England sold all of its car badges. It's amazing it's still got a cottage industry of high performance companies.
Great interesting information on engine devleopment I enjoy every minute of the discussion. Any chance you guys could do a Podcast on the late MV 500- 4 against rise of the 2 strokes in the 500's in the mid 1970's. This traced the developement of the 4 valve heads in the modern era.
Wow. The technical knowledge here is amazing. What I remember about the RS750 is what they did on the track. I remember Bubba Shobert, Dan Ingram, Ricky Graham and Doug Chandler. They had some amazing runs on these bikes. I used to watch them at the Sacramento and San Jose Miles all through the 80's. Matching up against Harley Riders like Scott Parker, the Springer and Chris Carr. I can honestly say those are some of the most hotly contested, crazy, fun , amazing races I have ever seen. The only thing that bummed me out is after Bubba cleaned house for a couple of seasons, factory Honda just picked up shop and abandoned the whole program. In my dreams I was hoping that Honda would come out with a street legal flat tracker based on the RS750. Oh well.
Another great informative podcast from the two best holdovers of the print era. I panicked when CW abandoned its print format, but the blog chats go a long way to ameliorate the loss of paper issues. Re: the RS Honda,; I think I read that the Honda somehow ended up with the exact same bore and stroke as the XR Harley. In effect, just barely oversquare. Great overview of a collaborative project that got Honda traveling along the Flattrack racing scene. It even seemed to influence their Street Bike styling in the early 80s (Ascot single and and Vtwin, and the Nighthawk series). I do wish that American Flattrack racing got the notice it deserves. I grew up in the time before MX took off, and I recall there seemed to be little dirt tracks everywhere. It was cool to watch the 2-strokes overshadow the previously dominant 4-strokes in the 250 class. A TD-1 Yamaha “framer” against a Sprint single; glory days! And the fields were deep, even at the local level. What happened? There’s an idea for a podcast. Thank you for the podcasts.
I heard that NASCAR Sanctions AMA Pro Flat Track. They made a couple of Improvements, More air fencing and requiring riders to wear air suits. The Pay out does not cover much more than Gas Money for Teams to get to the races. There are a few riders making Good Money in Motocross. The Premier 750 Super Twins Class was not getting a full Grid, so the AMA & NASCAR deleted the Factory Twins Class. I believe this class was important to get more riders race time building up to the Priemer class. Factory Twins was supposed to be a more affordable class. I don't think it was. Custom Frames and lots of money spent for better heads, cams rods and cranks for stoke street bike engines. The allowed displacement is all over the place. I believe the max displacement should be 750 CC's for all brands.
Loved the DuQuoin mile race particularly because on Sunday morning all the teams pitted outside the grandstands so you could get up close and personal with the bikes and riders, I have some great pictures from there of the Hondas.
@ 6:15 you reminded me; one of my great experiences was watching Ricky in Vegas ('93) before his tragic end! Love to listen-you guys are so smart! Also, i remember Kevin (once) giving a perfect explanation (in CW), about WHY Harley is so popular. That made sense.
My first memory of the RS750 was on the clay half mile at Hagerstown maryland seeing Shobert coming off turn 4 both feet on the pegs running wide open in the 80s
At the 40.44 mark talking about Hayden falling because he hit a bump with the forks bottomed out on the brakes. Maybe Bagnaia’s tire is the difference. Lots of tire development since Nicky’s time.
A plain bearing bottom end adaptation is not as easy as it sounds. Can you still use the fork and blade big ends? I don’t think so. So now you have to run the big ends side by side. Now suddenly the cam arrangement becomes even more complicated. Oil scavenging rears its head again. The crankcases are no longer narrow. New frame needed.
Thank you for the info on the NS and RS. I loved that bike in the dirt track racing series! And thank you so very much for going down the rabbit holes! So what about that "Kawasaki" parallel twin that was winning in the late '10's? Where did it go? How about a mention of the "twingles"? Mark, it's a good thing you suppressed that sneeze, who knows where your 'stache would have ended up.
Almost forgot; Regarding the Dirt Trackers; The HD complaining to AMA to slow the HONDA was nothing new, they did it anytime they got beat, even more so the Brit's, in those days HD was 750cc and Brits 500cc! Mann beat them with a G50 for his Gran National Championship! Bike then banned! Finally AMA allowed the 650 later 750 vertical twins. I road raced a Triumph twin from 1979-1996 then again 2004, this was a T140. The best help ever was from Jack Wilson at Big-D Triumph in Dallas, I can hear his Texas drawl now... YES SIR! Ya know you're making that horse power when you're breaking them crankshafts!" This he said to me at Laguna National 1985 when I lead every lap BoTT Mod Prod race until crank broke in corkscrew! The mod he had me do to the new crank worked, as it never broke again! He talked of adding weight to the flywheel places like the mile and Daytona!
I wonder how flattrack would have looked like over the years if King Kenny's TZ750 flattracker wasn't banned? Can anyone imagine a full grid of TZ 750s????
Improving the breed always upsets the reigning....Put up, shut up or get outta da way...Well, I'm gonna cry to "Momma" and keep you out of my sandbox, correct AMA/HD?
The Honda RS-750 put a beat down on the Harleys, but then again Ricky Graham was one of the Most Talented Flat Track Racers of all times. I don't know as much about Bubba Shobert, but sounds like he was very good too.
Fielding a team of Chandler, Graham, and Shobert led to some of the most iconic racing I will ever see in my lifetime. Arguably some of the most dangerous yet respectful battles of any discipline. Would have loved to have heard more about them in particular in the discussion. Good stuff nevertheless gentlemen, keep up the great work !!
typical AMA pro Harley Davidson- they just couldn't stand the sight of anything with GOLD WINGS on it beating the daylight out or there antiquated pushrod piles of shit - RIP RICKY GRAHME
Correct me if I'm incorrect but torque is a resultant of how fast you create rotation....the correlation of "horsepower" is an rpm factor/constant after the torque creation flattens and reflects the rpm capability of the mechanical strength of engine component materials....
Torque is a component of horsepower, not very useful by itself. A 5 gallon bucket of water hanging on a cantilevered 2×4×8 creates more torque at the other end than an rs750, but is not very useful at doing work, such as accelerating a motorcycle. Hp=(TQ×RPM)/5252. Without rpm, you have zero. Or a hanging bucket or something similar.
Cylinder fin gapping induces more surface area for cooling......then resonances made the parted fins crack....hence, rubber plugs, never mind engine "ringing"...."ringing", eh?
Talking about oil control rings and piston cooling oil squirters and aircraft engines makes me wonder about oil control issues in inverted engines. It seems like oil would pool in the upside down pistons.
I believe it was Kevin in a long ago article, said part of the radial engine start up procedure was to remove the plug(s) and Drain the oil that has pooled below the pistons. Idk about the solution above. Interesting for sure.
@@BastardX13 They actually rotate the engines backwards by hand to clear the cylinders of oil. Pulling the plugs is quite a process on an aircraft engine.
Harley should have changed the lower end to plain bearings and got rid of pushrods and built a modern engine. It doesn't need to potato either. I remember at Springfield when Graham fell in turn one, they pulled him out of the hay bales, he restarted dead last and finished third. All with a weighted and restricted Honda. Speaking of beauty, racing at Springfield is ballet- Back when Suzuki and Ducati and Kawasaki v twins came racing with their 1000cc bikes none of them would hook up. XR 750's were faster.
In 1983 the AMA approved the Honda RS750D for Class C flat track competition. Honda successfully conned the AMA Rules Committee into believing that the RS750D’s engine was based on their XLV750R shaft-drive dual-sport bike introduced into the European market in 1982. Which was nonsense! Given the XLV750R’s engine had a 52-degree V-angle, with an offset pin crankshaft, and the RS750D was a 45-degree V-angle engine with a single pin crank and with chain drive, it was obvious that this was a cynical ploy and the engine violated the rule promulgated in 1932 requiring Class C flat track motorcycles to be based on production models. Furthermore, the XLV750R was not sold in America as required by the rules The RS750D engine was without question a race-only engine. A "cheater". The AMA was bought off by Honda money. Once the bugs were sorted out, Ricky Graham won the 1984 AMA Championship on a RS750D. Bubba Shobert then went on to win the Championship the following 3-years in a row, in 1985, 86’ and 87’, absolutely decimating the competition. But Honda had had enough after only 4-years and took their "cheater" RS750D''s home. Moving on to 2017, the American Flat Track Championship, the new name for the Grand National, promulgated new rules for AFT twins, the top class. In summary two subsets of engines were approved. “Production-based” motors limited to 998cc, and “Race-only” motors limited to 750cc. Old timers thought.. “Oh no! Here we go again!” The AMA was bribed ~ by Polaris deep pocket money this time. Its "Indian in name only" FTR750 was a special race bike with a race only-engine. Hand built in Switzerland by a company that builds prototype MotoGP engines. This engine was not available in any production street bike ~ as required by Class C rules promulgated in 1932. And as to be expected the results mirrored the results obtained by the Honda RS750D route in the 80’s. These “Indian in name only” motorcycles, with their race-only engines, decimated the field of production engine bikes in the same way the RS750D’s did. A sorry state of affairs. And one oblivious to all casual fans. Polaris, like Honda has pulled off one massive con job.
THE GOOD NEWS: For 2025 the FTR750 has been banned. AMA Pro Racing has been persuaded to follow the Class C rules ~ and balance will be restored. Polaris has to “hot rod” one of their street bike engines to compete against the Harley-Davidson XG750R’s, Yamaha FZ-07’s, Kawasaki Ninja’s, and the Ducati’s and KTM’s. All of which are legitimate Class C bikes! The gravy train has ended for Polaris.
The AMA, for nearly a century, has repeatedly choked-off flatrack racing by driving everyone else out with rule changes that guarantee Harley wins. I have had AMA Competition licenses, but only because I had to. I despise them. If you come up with a successful series, the AMA will thug you, and then ruin it. I give you Supermoto & vintage racing. Motocross the only survivor of their "help."
Smokey Yunick noticed that a roller bearing engine was much easier to turn over by hand. He converted a plain bearing engine to all roller bearings. Yes it was easier to turn over manually on the engine stand, but did not gain anything on the Dyno. Trial and error is one way to find things out. XR-750's need to be rebuilt every weekend. The FTR-750 Indian needs to be rebuilt every 40 hours.
@@mikeskidmore6754 Years back plenty of automobile engines and even aircraft engine's like the early German DB engines that powered the ME109 had roller bearings in them, the reason was because of the oils of that era, they couldn't provide the constant layer of lubrication that the journals have to ride on necessary for babbitt bearings, they were just oil and didn't have the additives that were developed as time went on. Believe it or not about ¼ of today's motor oils by volume are its additives, if you took a gallon of today's oil and removed the additives you'd only have about 3 quarts left, roller bearings require much less oil to survive, look at the roller bearings in the front rotor on old American cars, you pack the bearings putting one together but after it rotates just a short while all that grease has squished out and only a tiny amount keeps lubricating them from it trickling back in, if you were to put a babbitt bearing in the same environment it'd burn up in no time.
@@dukecraig2402 Roller bearings only need to be wet such as in splash Lubrication. Plain Bearings need oil pressure from an oil pump. That pressure keeps enough oil between the two metal surfaces to keep them galling and seizing. plain bearings need a very thin film of oil. The oil also carries heat away from critical spots.
The definitive work on the topic is a book titled, “When Honda Went Dirt Track Racing”. Available on the Motion Pro website. A little pricy but exhaustive in detail.
You don't like pneumatics vs. hydraulics re your 460 truck problems....woah. Air vs. Liquid cooling....Air and oil don't like each other: "keep'em seperated"
Harley is just a stubborn company saved ONLY by what I consider a Fad they stumbled into via no original intent. The big Vee chopper / biker image just thrived with the LOOK the sound and the vibration of a defunct old tech motor that is so distinct from all the other designs most of which were trying to engineer superior more modern designs. Harley sold well for the same reason Levi Jeans did because they just gained the "cool" stamp of approval by the style police. FINALLY after all these decades it is biting them in their @$$ as their base dies off of old age....I dont think anything will ever stop the Harley motor from looking iconic but there are plenty of other iconic looks also and not only that ALL the more modern designs that were originally not iconic? Now THEY are also which just eventually leaves the ones with the most liabilities to be dismissed by shoppers wanting the best or even the bestish at the vest deal. Anyway as for flat track engines? The RS750 hands down looks way cooler than the XR.....IMHO I mean the Japanese have multiple times made better big Vee twins than the Motor Company ever did....just people kept wanting REAL Levi 501jeans so they did not get caught out with imitations lacking the logo
I am 68 years old and grew up reading the American magazines. I learned so much from Gordon Jennings and Kevin as they explained so much more than just putting parts together. With a lot personality thrown in I might add. I have been very fortunate to have been involved in our sport during this time. Thanks to you Mark for your contribution as well. I do miss paper mags though. Good stuff guys, really enjoy these.
As one of the people currently developing the KTM for flat track I can tell you you're absolutely correct. Modifying the crank pistons, head and cam are costly. Way over 10K for. But who really cares about that. Its exciting to develop another motor and see what it can become
One of my favorite bikes, as an original 1978 CX500 owner I watched the development progress to this fantastic conclusion. Another great episode! Thanks
CX500 one more very cool Japanese models no one asked for man there were so many others how about the Yamaha 550 Vision? One year wonder....really interesting even apealing but not any great reason to go buy one....building stuff no one asked for....a big file folder
I think the vision is related to the Venture, therefore the Vmax, also. I remember in the Venture Royale test in 83, either Cycle, Cycle World, or Cycle Guide called it a "double vision", implying that the venture was based on the vision. Probably not, they were likely designed at the same time, but I don't know.
I think they were a 2 year bike..one year with diaphragm butterfly valve carbs, the other with more typical CV carbs.
I think they're good looking
The cx650s sure run better than the 500s, which were just dogs..a cx650custom (short wheelbase) does pretty good wheelies. Then you smash your shins on the valve covers....ouch! Former Honda/yamaha mechanic from the 80s/90s, so got to ride them.
You probably know the CX's are pushrod, cam in block motors, with 4 valves per cyl. Combustion chamber centerline is twisted relative to the crank. Weird, but pretty good
I didn't know torque came from the compression ratio, learning stuff here. Great chat guys thanks.
Or more being one good way to increase torque?
just a force times a distance up to u how you do it ,,,more force or more radius
Yea, I never thought of it this way, but it makes total sense. Just look at diesel engines.
I started competitively racing pull start minibikes 3 years ago, one of the fast guys told me last year “you wanna be fast? Get your compression ratio up around 12.5 to 13:1”
I’ll be about 12.5-12.7 with this new 236cc engine I’m building for next season.
But on the other hand you don’t want tooooo much compression on a single cylinder, for longevity at least. It doesn’t have a companion cylinder to help push it back up. That’s what I have read at least.
Some of the best motorcycle racing I’ve ever seen were the Daytona Stadium flat trackers. They are the sprintcars of the two wheeled racing world. As much as I loved the XR’s, the cahoots of the Motor Company and the AMA screwed innovation in the name of preservation of tradition.
On the suspension discussion, I was a stock car guy. Once I got the concept of “suspension doesn’t hold the vehicle up it holds the tires down and complying with the surfaces of the track” my chassis and suspension setups and success improved immensely!
As always excellent content!
Not a technical guy, just a racer, but really enjoy listening to you guys 🙏
The AMA killed flat track racing long ago. If it wasn’t for the AMA you could go into your local Honda, Yamaha, Suzuki or Kawasaki dealer and buy an almost race ready flat tracker just as you can buy a MX or Enduro bike now.
and Bultaco for a few years.
That's laughable and for the life of me I couldn't even begin to imagine the logic process that comes up with that.
The AMA doesn't tell motorcycle manufacturers what they can sell and what they can't, and if manufacturers don't have a factory flat track racing program, or if they have one and pull the plug on it like Honda did with theirs in the 80's, that's on them.
The Japanese motorcycle manufacturers put their money into Superbike racing programs because that's what sells their motorcycles, everyone who's into Japanese motorcycles don't go anywhere near flat track races, so why would the Japanese manufacturers dump millions into a flat track racing program? There's no payoff for it.
And what killed flat track popularity in the US was motorcross and supercross, that was a sport where some kid whose dad had a little bit of money could get a dirt bike and hit a local track to see if he had what it takes, hardly nobody's dad has the kind of money to get them into flat track, but 45+ years ago if your dad bought you an Elsinore you could go racing.
What really made teenage kids in America hot to race motorcross was in 1980 when Marty Moates beat all the best European riders in the US Grand Prix, before that every year everyone watched the best riders in the world come over from Europe and take an American trophy home with them, but then in 1980 an underdog privateer beat all of them and overnight every kid in America dreamed about being the next Marty Moates and motorcross exploded in popularity and the stands at flat track racing drained.
@@dukecraig2402 There were a lot of Armatures racing Motocross from 1970 to 1980 also. Every weekend they had 100 CC 125 CC 175 CC 250 CC and Open classes. 125-A 125-B and 125-C classes ect. Motocross was way more popular in the amateur ranks back then than it is now. When a New Race bike cost $600.00 or a bit more new. People went to the races with an old Van a pickup or a car with a 3 place open trailer behind it. You didn't have to be all that good to be competitive compared to now days where you need to go to racing schools and have coaches and a practice Track ect.
Okay Motor Company Rent Boi!
@mikeskidmore6754
I know, I was a teenager back then, I did say that European riders came over to America didn't I? And didn't I give a time frame of "45+" years and mention the Honda Elsinore both of which puts that part of my comment solidly in the 1970's? So obviously motorcross racing was going on here and yes I knew about it at the time, my point is it really exploded after Moates won the US Grand Prix and is what really shifted popularity away from flat track racing and into motorcross.
A good example is in the 1976 movie The Bad News Bears, the scene where Kelly Leak is in the dance studio trying to pick up that woman that looks like she's 30 (which is hysterical and I still laugh at it, "You like motorcycles? I got a Harley."), if you look at his Tshirt it has a "Flat Tracker" iron-on on the front of it, 5 years later it'd have been a motorcross iron-on because kids didn't want to go to flat track races anymore, they wanted their dads to take them to motocross races even if they weren't racing themselves, their heroes shifted from flat track racers to dirt bike racers, that more than anything else is what killed the popularity of flat track, not anything the AMA did, not all this conspiracy nonsense everyone's always throwing around about the AMA supposedly inventing rules to favor Harley, that's all nothing but people popping off who don't know anything about flat track or its history, a perfect example is everyone always saying that the AMA limited OHV engines to 500cc in the 60's to keep the British bikes from beating Harley, that rule was enacted in 1932 when there was over 130 motorcycle manufacturers in the US and long before anyone brought a bike from overseas to race on county fair dirt horse racing tracks.
It's amazing the people who know nothing about the sport, have never even been to a flat track race in their life but they talk about it like they're an expert on the subject, it's the single most misunderstood form of motorcycle racing there is because people aren't into like years ago but oh boy, when it comes time to talk about it they're instant experts.
Flat tracking is great. As a kid it was the first motorcycle race I ever saw. Wanted a better view, worked up to the fence, peered over and got a face full of dirt. It was great.
"Lots of little people with matches..."
So interesting to hear about Gene Romero's role in development of the RS750. I saw him race many times, great to learn that his expertise was valued as a contributor to that project.
So good to hear you guys talk about Jeff Haney.
That guy is an absolute legend, i always wonder what his carreer would have looked like, if a big team took him in.
His results on the CX and NS, damaged his carreer, but those results sure as hell were not to blame on Jeff’s talent for riding.
I was lucky to attend the San Jose Mile on several occasions. Being there and watching the riders move around at speed on the bikes combined with the smells and sounds was glorious. TV watching is great, but a live flat track race belongs on ones bucket list.
TGIW!! Bubba Shobert and Ricky Graham!!! Remember the 93 Season of Flattrack!? Ricky DOMINATED that year on his HONDA!!
It was either 1982 or 83 I was at the Springfield mile and had an infield pass courtesy of a Honda dealer. Honda showed up with 3 bikes, 2 were modified CX liquid cooled and 1 was the new aircooled purpose built racer. Mike Kidd and Terry Poovie were on the liquid cooled bikes and Hank Scott was on the race bike. Harley had a factory team of 5 or more riders, Jay Springsteen being one of them and my personal favorite.
In the end, after a rain delay, Hank Scott won on the new Honda race bike and leather clad Harley riders in the grandstand were anything but happy. Needless to say, if the AMA wanted to keep their primary fan base buying tickets and new HDs they had to slow down the competition (Honda).
In support of the farmer analogy, I'll draw attention to Carroll Shelby, former chicken farmer. Shelby's cars were kept simple, sometimes to the point of being crude, but they did get the hay into the barn reliably.
Remember that era well. Thanks guys.
Morning from Australia gentlemen.
Is that sort of a bit oxymoronic? "austrailian" and "gentlemen" ?? lol j/k
@@dougiequick1Dougie, I am trying to maintain some sort of international cordiality and manners. . . . . 😁
Great podcast. Thanks
With the mustache I'm watching Hoyer slowly morph into James Hetfield.
This was the fake cooling fin era. I really liked the Honda VT 500 flat track. The offset crankpin and shaft drive. There may have been something about not going any narrower because of intake interferance like H-D 45 degree. I think it was the smallest bike with shaft drive in Canada. Honda also sold the FT500.
The Chevy/Ilmor V8 was interesting for having quite short pushrods. They raised the camshaft in the block and had porcupine pushrods.
Apparentley Kieth Duckworth was working on a two stroke boxer with a university before he passed away - maybe something to do with generation in developing countries.
England sold all of its car badges. It's amazing it's still got a cottage industry of high performance companies.
Great interesting information on engine devleopment I enjoy every minute of the discussion. Any chance you guys could do a Podcast on the late MV 500- 4 against rise of the 2 strokes in the 500's in the mid 1970's. This traced the developement of the 4 valve heads in the modern era.
Wow. The technical knowledge here is amazing. What I remember about the RS750 is what they did on the track. I remember Bubba Shobert, Dan Ingram, Ricky Graham and Doug Chandler. They had some amazing runs on these bikes. I used to watch them at the Sacramento and San Jose Miles all through the 80's. Matching up against Harley Riders like Scott Parker, the Springer and Chris Carr. I can honestly say those are some of the most hotly contested, crazy, fun , amazing races I have ever seen. The only thing that bummed me out is after Bubba cleaned house for a couple of seasons, factory Honda just picked up shop and abandoned the whole program. In my dreams I was hoping that Honda would come out with a street legal flat tracker based on the RS750. Oh well.
@WilliamsThomas-d3m A RS750 based Streetracker!!! Yes please! It would have been better than those Ascots Honda built.
Another great informative podcast from the two best holdovers of the print era. I panicked when CW abandoned its print format, but the blog chats go a long way to ameliorate the loss of paper issues.
Re: the RS Honda,; I think I read that the Honda somehow ended up with the exact same bore and stroke as the XR Harley. In effect, just barely oversquare.
Great overview of a collaborative project that got Honda traveling along the Flattrack racing scene.
It even seemed to influence their Street Bike styling in the early 80s (Ascot single and and Vtwin, and the Nighthawk series).
I do wish that American Flattrack racing got the notice it deserves. I grew up in the time before MX took off, and I recall there seemed to be little dirt tracks everywhere.
It was cool to watch the 2-strokes overshadow the previously dominant 4-strokes in the 250 class. A TD-1 Yamaha “framer” against a Sprint single; glory days!
And the fields were deep, even at the local level.
What happened? There’s an idea for a podcast.
Thank you for the podcasts.
Looking forward to seeing new 750s from Indian and Harley due to next year's rules changes.
Lots of little people with matches trying to hand them to each other! What a great metaphor.
I heard that NASCAR Sanctions AMA Pro Flat Track. They made a couple of Improvements, More air fencing and requiring riders to wear air suits.
The Pay out does not cover much more than Gas Money for Teams to get to the races. There are a few riders making Good Money in Motocross.
The Premier 750 Super Twins Class was not getting a full Grid, so the AMA & NASCAR deleted the Factory Twins Class. I believe this class was important to get more riders race time building up to the Priemer class. Factory Twins was supposed to be a more affordable class. I don't think it was. Custom Frames and lots of money spent for better heads, cams rods and cranks for stoke street bike engines. The allowed displacement is all over the place. I believe the max displacement should be 750 CC's for all brands.
Loved the DuQuoin mile race particularly because on Sunday morning all the teams pitted outside the grandstands so you could get up close and personal with the bikes and riders, I have some great pictures from there of the Hondas.
Love the flat track episodes. Probably my second favorite moto sport after MotoGP.
@ 6:15 you reminded me; one of my great experiences was watching Ricky in Vegas ('93) before his tragic end!
Love to listen-you guys are so smart!
Also, i remember Kevin (once) giving a perfect explanation (in CW), about WHY Harley is so popular. That made sense.
My first memory of the RS750 was on the clay half mile at Hagerstown maryland seeing Shobert coming off turn 4 both feet on the pegs running wide open in the 80s
Love listening to you Kevin.
Another great video very interesting.hi from New Zealand 🇳🇿
love this podcast - thanks guys
At the 40.44 mark talking about Hayden falling because he hit a bump with the forks bottomed out on the brakes. Maybe Bagnaia’s tire is the difference. Lots of tire development since Nicky’s time.
A plain bearing bottom end adaptation is not as easy as it sounds. Can you still use the fork and blade big ends? I don’t think so. So now you have to run the big ends side by side. Now suddenly the cam arrangement becomes even more complicated. Oil scavenging rears its head again. The crankcases are no longer narrow. New frame needed.
Maintenance tips with Mark!!!
Any old Georgia boys here? Remember Holiday Downs in Palmetto? Lots of great 3/8 mile banked dirt racing.
Thank you for the info on the NS and RS.
I loved that bike in the dirt track racing series!
And thank you so very much for going down the rabbit holes!
So what about that "Kawasaki" parallel twin that was winning in the late '10's?
Where did it go?
How about a mention of the "twingles"?
Mark, it's a good thing you suppressed that sneeze, who knows where your 'stache would have ended up.
Almost forgot; Regarding the Dirt Trackers; The HD complaining to AMA to slow the HONDA was nothing new, they did it anytime they got beat, even more so the Brit's, in those days HD was 750cc and Brits 500cc! Mann beat them with a G50 for his Gran National Championship! Bike then banned! Finally AMA allowed the 650 later 750 vertical twins. I road raced a Triumph twin from 1979-1996 then again 2004, this was a T140. The best help ever was from Jack Wilson at Big-D Triumph in Dallas, I can hear his Texas drawl now... YES SIR! Ya know you're making that horse power when you're breaking them crankshafts!" This he said to me at Laguna National 1985 when I lead every lap BoTT Mod Prod race until crank broke in corkscrew! The mod he had me do to the new crank worked, as it never broke again! He talked of adding weight to the flywheel places like the mile and Daytona!
Just so ya know Kev, mimicry is the greatest form of flattery.
I hand machined all the rear hubs for the first CX powered bies, fun memories.
I wonder how flattrack would have looked like over the years if King Kenny's TZ750 flattracker wasn't banned? Can anyone imagine a full grid of TZ 750s????
Improving the breed always upsets the reigning....Put up, shut up or get outta da way...Well, I'm gonna cry to "Momma" and keep you out of my sandbox, correct AMA/HD?
Remembering changes that I made to the bike and getting it wrong.
No Kevin to ask for help.
I did grow up on a farm.
Talking about the 135hp crate engine made me visualize one of the super wide street bike tires with a dirt track tread pattern 🤪
Flat Track King Of The Baggers Racing anyone? 🤣
Fascinating topic 😊
The Honda RS-750 put a beat down on the Harleys, but then again Ricky Graham was one of the Most Talented Flat Track Racers of all times. I don't know as much about Bubba Shobert, but sounds like he was very good too.
Fielding a team of Chandler, Graham, and Shobert led to some of the most iconic racing I will ever see in my lifetime. Arguably some of the most dangerous yet respectful battles of any discipline. Would have loved to have heard more about them in particular in the discussion. Good stuff nevertheless gentlemen, keep up the great work !!
@@paulshank7055 You might be able to find some of those races on youtube.
typical AMA pro Harley Davidson- they just couldn't stand the sight of anything with GOLD WINGS on it beating the daylight out or there antiquated pushrod piles of shit - RIP RICKY GRAHME
Love the discussion. Hate zero graphics. JfOH
Great videos! How about one on the rise and fall of V-Twins in Moto GP?
HD is loosing $100 Million per year on their Electric bikes. Not a good business move.
Stories about the Honda RS600 please
Correct me if I'm incorrect but torque is a resultant of how fast you create rotation....the correlation of "horsepower" is an rpm factor/constant after the torque creation flattens and reflects the rpm capability of the mechanical strength of engine component materials....
Consider yourself corrected…
Torque is a component of horsepower, not very useful by itself. A 5 gallon bucket of water hanging on a cantilevered 2×4×8 creates more torque at the other end than an rs750, but is not very useful at doing work, such as accelerating a motorcycle.
Hp=(TQ×RPM)/5252. Without rpm, you have zero. Or a hanging bucket or something similar.
This makes me want to be right there, right then
Remember the "Shwarup" intake bs from the 80's?
Gent's
Can we have a full session on how brake systems work?
Kevin and Mark just recorded one on brakes this week. Won’t be long before it’s published. Thanks for listening!
Cylinder fin gapping induces more surface area for cooling......then resonances made the parted fins crack....hence, rubber plugs, never mind engine "ringing"...."ringing", eh?
Didn't the AMA put a 30# or 40# weight Restriction on the Honda Flat Trackers too?
Talking about oil control rings and piston cooling oil squirters and aircraft engines makes me wonder about oil control issues in inverted engines. It seems like oil would pool in the upside down pistons.
I believe it was Kevin in a long ago article, said part of the radial engine start up procedure was to remove the plug(s) and Drain the oil that has pooled below the pistons. Idk about the solution above. Interesting for sure.
@@BastardX13 They actually rotate the engines backwards by hand to clear the cylinders of oil. Pulling the plugs is quite a process on an aircraft engine.
@truthboomertruthbomber5125 Thanks.
Harley should have changed the lower end to plain bearings and got rid of pushrods and built a modern engine. It doesn't need to potato either. I remember at Springfield when Graham fell in turn one, they pulled him out of the hay bales, he restarted dead last and finished third. All with a weighted and restricted Honda. Speaking of beauty, racing at Springfield is ballet- Back when Suzuki and Ducati and Kawasaki v twins came racing with their 1000cc bikes none of them would hook up. XR 750's were faster.
A Swiss-engined Indian FTR? Boy, where'd HD/XR go? Farmers riding flat trackers....good one
In 1983 the AMA approved the Honda RS750D for Class C flat track competition. Honda successfully conned the AMA Rules Committee into believing that the RS750D’s engine was based on their XLV750R shaft-drive dual-sport bike introduced into the European market in 1982. Which was nonsense!
Given the XLV750R’s engine had a 52-degree V-angle, with an offset pin crankshaft, and the RS750D was a 45-degree V-angle engine with a single pin crank and with chain drive, it was obvious that this was a cynical ploy and the engine violated the rule promulgated in 1932 requiring Class C flat track motorcycles to be based on production models. Furthermore, the XLV750R was not sold in America as required by the rules
The RS750D engine was without question a race-only engine. A "cheater". The AMA was bought off by Honda money.
Once the bugs were sorted out, Ricky Graham won the 1984 AMA Championship on a RS750D. Bubba Shobert then went on to win the Championship the following 3-years in a row, in 1985, 86’ and 87’, absolutely decimating the competition. But Honda had had enough after only 4-years and took their "cheater" RS750D''s home.
Moving on to 2017, the American Flat Track Championship, the new name for the Grand National, promulgated new rules for AFT twins, the top class. In summary two subsets of engines were approved. “Production-based” motors limited to 998cc, and “Race-only” motors limited to 750cc.
Old timers thought.. “Oh no! Here we go again!” The AMA was bribed ~ by Polaris deep pocket money this time. Its "Indian in name only" FTR750 was a special race bike with a race only-engine. Hand built in Switzerland by a company that builds prototype MotoGP engines. This engine was not available in any production street bike ~ as required by Class C rules promulgated in 1932. And as to be expected the results mirrored the results obtained by the Honda RS750D route in the 80’s. These “Indian in name only” motorcycles, with their race-only engines, decimated the field of production engine bikes in the same way the RS750D’s did.
A sorry state of affairs. And one oblivious to all casual fans. Polaris, like Honda has pulled off one massive con job.
THE GOOD NEWS: For 2025 the FTR750 has been banned. AMA Pro Racing has been persuaded to follow the Class C rules ~ and balance will be restored. Polaris has to “hot rod” one of their street bike engines to compete against the Harley-Davidson XG750R’s, Yamaha FZ-07’s, Kawasaki Ninja’s, and the Ducati’s and KTM’s. All of which are legitimate Class C bikes! The gravy train has ended for Polaris.
(Actually, if your bike is powered by a rocket engine it has to hook up to turn, not to go.)
#LONGLIVETHEFTR750
#LOGLIVETHEXR750
#MAKEAMERICANFLATTRACKGREATAGAIN
The AMA, for nearly a century, has repeatedly choked-off flatrack racing by driving everyone else out with rule changes that guarantee Harley wins. I have had AMA Competition licenses, but only because I had to. I despise them. If you come up with a successful series, the AMA will thug you, and then ruin it. I give you Supermoto & vintage racing. Motocross the only survivor of their "help."
Restrictions plates? My "sandbox" bs.
Smokey Yunick noticed that a roller bearing engine was much easier to turn over by hand. He converted a plain bearing engine to all roller bearings. Yes it was easier to turn over manually on the engine stand, but did not gain anything on the Dyno. Trial and error is one way to find things out.
XR-750's need to be rebuilt every weekend. The FTR-750 Indian needs to be rebuilt every 40 hours.
@@mikeskidmore6754
Years back plenty of automobile engines and even aircraft engine's like the early German DB engines that powered the ME109 had roller bearings in them, the reason was because of the oils of that era, they couldn't provide the constant layer of lubrication that the journals have to ride on necessary for babbitt bearings, they were just oil and didn't have the additives that were developed as time went on.
Believe it or not about ¼ of today's motor oils by volume are its additives, if you took a gallon of today's oil and removed the additives you'd only have about 3 quarts left, roller bearings require much less oil to survive, look at the roller bearings in the front rotor on old American cars, you pack the bearings putting one together but after it rotates just a short while all that grease has squished out and only a tiny amount keeps lubricating them from it trickling back in, if you were to put a babbitt bearing in the same environment it'd burn up in no time.
@@dukecraig2402 Roller bearings only need to be wet such as in splash Lubrication. Plain Bearings need oil pressure from an oil pump. That pressure keeps enough oil between the two metal surfaces to keep them galling and seizing. plain bearings need a very thin film of oil. The oil also carries heat away from critical spots.
I thought this podcast was aboyt the RS750.....
The definitive work on the topic is a book titled, “When Honda Went Dirt Track Racing”. Available on the Motion Pro website.
A little pricy but exhaustive in detail.
Butaco 650 make over !
As the Japanese have always done, even with subsequent failures then rectified, copied the "known"......improving the breed.
51:35 Drink! 😂
Volumetric efficiency and combustion efficiency are inherently opposed.
You don't like pneumatics vs. hydraulics re your 460 truck problems....woah. Air vs. Liquid cooling....Air and oil don't like each other: "keep'em seperated"
Lose the stash
Harley is just a stubborn company saved ONLY by what I consider a Fad they stumbled into via no original intent. The big Vee chopper / biker image just thrived with the LOOK the sound and the vibration of a defunct old tech motor that is so distinct from all the other designs most of which were trying to engineer superior more modern designs. Harley sold well for the same reason Levi Jeans did because they just gained the "cool" stamp of approval by the style police. FINALLY after all these decades it is biting them in their @$$ as their base dies off of old age....I dont think anything will ever stop the Harley motor from looking iconic but there are plenty of other iconic looks also and not only that ALL the more modern designs that were originally not iconic? Now THEY are also which just eventually leaves the ones with the most liabilities to be dismissed by shoppers wanting the best or even the bestish at the vest deal. Anyway as for flat track engines? The RS750 hands down looks way cooler than the XR.....IMHO I mean the Japanese have multiple times made better big Vee twins than the Motor Company ever did....just people kept wanting REAL Levi 501jeans so they did not get caught out with imitations lacking the logo
If you can't put it down to the ground, yous is just spinning yous ass end...