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Can anyone explain the timeline of the switch from 2 stroke to 4 stroke in racing?

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I watched a youtube vid last night that was like 2 hours long and went through all of the Supercross races in 2005.  The year Carmichael wast the points champion and also the points champion for some world title.  I think it was FIM (not sure what that was and how he won it...  )  Anyways....

 

From what I could gather nearly all of the bikes were 2 strokes except for a few.   I remember going to a supercross event in Illinois in either 1999 or 2000 and I think there was also maybe one or two 450 4 strokes but I believe the rest were 2 stroke.   If memory serves me correct I think one of the 4 strokers was a Yamaha but I don't remember who was riding it. 

 

Anyways....  I'm totally confused as to the status and timeline of all that.  I'm not sure what knowing will bring me other than when looking at used bikes it's nice to understand the trends of the times.  I read this article that said the Japanese manufactures were all in on engineering newer things for 4 strokes by the mid 2000's for the competitors but like I said, that 2005 year supercross they were majority 2 strokes. 

 

I realize there were other disciplines.  Supercross, motocross, and also enduros.  And I guess trials bikes were more 4 strokes eh?   I"m assuming supermotos were always 4 strokes but I don't even really know that answer.  LOL. 

 

If someone can sort of give me a cliffs notes of the timelines and switches and what discipline was doing what, I would love that.   And I'm mainly concerned about American racing but that might only be part of the story so if someone has a handle as to what was happening over seas and it's pertinent, I'm all ears.  

 

The one article I read said that in 2005 power valves came about in 2 strokers and the power delivery was more more manageable with more low end and consistency in delivery.   Which piques my interest.   I don't even know what a power valve is.  I'm not real knowledgeable about 2 strokes but I want to learn.  I've got a buddy who has a 1990 RM-Z 250 he has sitting that he might fix back up and get it out to trail ride and I'm just curious as to the mechanics of both in general.  But I'm much more familiar with 4 stroke engines. 

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33 minutes ago, 3S1M said:

I watched a youtube vid last night that was like 2 hours long and went through all of the Supercross races in 2005.  The year Carmichael wast the points champion and also the points champion for some world title.  I think it was FIM (not sure what that was and how he won it...  )  Anyways....

 

From what I could gather nearly all of the bikes were 2 strokes except for a few.   I remember going to a supercross event in Illinois in either 1999 or 2000 and I think there was also maybe one or two 450 4 strokes but I believe the rest were 2 stroke.   If memory serves me correct I think one of the 4 strokers was a Yamaha but I don't remember who was riding it. 

 

Anyways....  I'm totally confused as to the status and timeline of all that.  I'm not sure what knowing will bring me other than when looking at used bikes it's nice to understand the trends of the times.  I read this article that said the Japanese manufactures were all in on engineering newer things for 4 strokes by the mid 2000's for the competitors but like I said, that 2005 year supercross they were majority 2 strokes. 

 

I realize there were other disciplines.  Supercross, motocross, and also enduros.  And I guess trials bikes were more 4 strokes eh?   I"m assuming supermotos were always 4 strokes but I don't even really know that answer.  LOL. 

 

If someone can sort of give me a cliffs notes of the timelines and switches and what discipline was doing what, I would love that.   And I'm mainly concerned about American racing but that might only be part of the story so if someone has a handle as to what was happening over seas and it's pertinent, I'm all ears.  

 

The one article I read said that in 2005 power valves came about in 2 strokers and the power delivery was more more manageable with more low end and consistency in delivery.   Which piques my interest.   I don't even know what a power valve is.  I'm not real knowledgeable about 2 strokes but I want to learn.  I've got a buddy who has a 1990 RM-Z 250 he has sitting that he might fix back up and get it out to trail ride and I'm just curious as to the mechanics of both in general.  But I'm much more familiar with 4 stroke engines. 

To my knowledge there was no RMZ250 in 1990. 2-strokes evolved with different configurations in engine design through the years. You are asking a lot in my opinion. If you want to study the motorcycle racing industry, You-Tube is a good place to start. (Mainly) motorcycle racing was street bikes for the Japanese brand to include Europe racing machines. I believe MX racing was introduced in Europe with modified street bikes. As it grew in popularity, the manufactures saw an opening to developing a dirt bike made for racing in the dirt. Suspensions evolved, basically all the dirt bikes that are now modern racing machine are high-end technology to make a rider comfortable to various track conditions. In all forms of racing "Research and Development" = R&D is very expensive. I too saw the first year of the 4-stroke dirt bike mixed in with 2-strokes in the Super-cross ranks. One rider from Europe raced a Yamaha. What year and the rider escapes me. But it was a very distinct sound compared to the 2-strokes. Yamaha had a 400cc 4-stroke  which was heavy as H3LL up against 250cc 2-strokes in MX back in the day. Dude it just grew from there.

Check out each individual Brand's history. You will learn a lot. There might be a few historians on TT to give a whole lot more input on your Topic. But just to give a hole-in-one comment, it would take all day to write that up if I am reading what you are asking for.  

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By 2005 most riders were on 4 strokes and 2 strokes were becoming a thing of the past. In the dirt bike world I think RC provided the last bit of proof needed to show 4 strokes are superior(at least at that time and with the cc rules in place). His last year on the 2 stroke with Honda he had some battles with Windham who was on Hondas 450 4 stroke. The next season RC switched to 4 stroke and once again it wasn't even a competition and he walked away with the championship.

The rules at the pro level allow 125cc 2 strokes to race against 250cc 4 strokes and 250cc 2 strokes to race against 450cc 4 strokes. So it's not really on a level playing field but there you have it.

Edited by Zinergy
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1 minute ago, Zinergy said:

By 2005 most riders were on 4 strokes and 2 strokes were becoming a thing of the past. In the dirt bike world I think RC provided the last bit of proof needed to show 4 strokes are superior(at least at that time and with the cc rules in place). His last year on the 2 stroke with Honda he had some battles with Windham who was on Hondas 450 4 stroke. The next season RC switched to 4 stroke and once again it wasn't even a competition and he walked away with the championship.

The rules at the pro level allow 125cc 2 strokes to race against 250cc 4 strokes and 250cc 2 strokes to race against 450cc 4 strokes. So it's not really on a level playing field but there you have it.

Ricky rode the RM250 2 stroke for SX, when he first switched.

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In 2005 that was the FIM World Supercross GP. It was a separate title they had for a few years back then and they ran two or three rounds outside of the US prior to the start of the AMA Supercross series in January. Those who chose to race them were in contention for both series points. In 1999 and 2000 the only four-strokes on a racetrack were Yamaha's, in the 250 class (now 450 class) and they would have been a YZ400F or YZ426F. John Dowd, Jimmy Button, Doug Henry if memory serves correct.

The 2005 SX season was the last that was predominately two-strokes (and won by a two-stroke), and the 2003 MX season was the last that was predominately two-strokes. In 2004 Factory Yamaha and Honda riders began riding four-strokes outdoors but stayed on two-strokes in SX. Suzuki and Kawasaki had a manufacturing partnership in 2004 until 2006 that made the RMZ-250 and KX250F the same bike, going their separate ways in 2007 and building different bikes. 2004 was the first year I remember four-strokes in the 125 class (now 250) although I'm pretty sure Nathan Ramsey or someone was on a CRF250R maybe one year before that. Ivan Tedesco won the title on his KX250F which was brand-new.

Supermoto was four-strokes. Converted YZ450F's and CRF450R's back when it was big and in the X-Games.

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In 97, Yamaha used their one works bike to run the first yz400/426 with Doug Henry. It was a full works bike, not production and he won the outdoor title on it. Yamaha then made the yz400 in 98,99, then a 426 in 00, 01, it became a 450 in 02 and the rest is history.

The changeover happened over a few years, if I remember correctly the 125 class went 4-st 100% first then the 250/450 class. The difference between a 125 and a 250 4-st was just too much for the 125 to remain competitive.

If you listen to whiskey throttle, they have discussed the cost, the first 400/426 ran $300-$600k per bike. The first PC 250’s had a short life and they had a new engine every race or sooner.

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1 hour ago, 3S1M said:

The one article I read said that in 2005 power valves came about in 2 strokers and the power delivery was more more manageable with more low end and consistency in delivery. 

Although some 80/85/500's never got them, 

power valves have been common on most 2-stroke MX race bikes since the mid-1980's.

 

They alter the exhaust port's height and size (duration and volume) which widens the engine's effective power band,

the somewhat equivalent to 'variable valve timing' in modern automobile engines.

Edited by mlatour
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I remember it being so cool hearing the first 4t at a sx race. Cool because it sounded like your buddies POS 3 wheeler and somehow it was doing good. It was pandora's shit box.

Fortunately, the sane, off road and trail riders are keeping the 2t alive and prospering. 4t are ridiculous on tracks without a doubt, but the majority of the population of riders cant maintain them, cant afford them, and cant even ride them without putting on a flat billed hat first

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7 minutes ago, Zinergy said:

&%$#@! you I don't own even 1 flat billed hat.

I think that's an old Chinese proverb. "One may not own a flat billed hat, the hat owns you" or something along those lines

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42 minutes ago, mlatour said:

Although some 80/85/500's never got them, 

power valves have been common on most 2-stroke MX race bikes since the mid-1980's.

 

They alter the exhaust port's height and size (duration and volume) which widens the engine's effective power band,

the somewhat equivalent to 'variable valve timing' in modern automobile engines.

Ya I just now noticed that also. Powervalves were on the modern bikes by the 80s. Not sure where the article got the 2005 from.

 

Basically (for the OP) riding a 2stroke that doesn't have a powervalve make the power spread a lot more like a light switch. So 2 strokes that have them have a much better transition from low rpm power to top when it is really screaming. But mlatour gave a very good technical response to how it works.

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Smaillance.jpg

KTM was the first manufacturer to take advantage of the Four-Stroke exemption rule, which allowed each manufacturer to race a non-homologated four-stroke machine for one season—with a displacement of as much as 550cc. Lance Smail would take the one-off KTM to the Daytona Supercross on March 8, 1997. When Lance’s KTM thundered into the Daytona main event during the semi, it was the first time a four-stroke had ever qualified for a premier class Supercross main event. Yamaha, which had lobbied for the four-stroke exemption rule for their YZ400, would become the first manufacturer to win an AMA Supercross on a four-stroke two months later when Doug Henry won the Las Vegas Supercross on May 17, 1997. Smail and KTM’s accomplish became a footnote in four-stroke history, but now you know.

Just so everyone remembers this correctly. 😛

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I think ill start wearing flat bills more now that i know it gets guys so much

Hopefully the dudes that are interested in judging other dudes apparel wont come talk to me after that lol

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2 hours ago, KnotAPro said:

To my knowledge there was no RMZ250 in 1990. 2-strokes evolved with different configurations in engine design through the years. You are asking a lot in my opinion. If you want to study the motorcycle racing industry, You-Tube is a good place to start. (Mainly) motorcycle racing was street bikes for the Japanese brand to include Europe racing machines. I believe MX racing was introduced in Europe with modified street bikes. As it grew in popularity, the manufactures saw an opening to developing a dirt bike made for racing in the dirt. Suspensions evolved, basically all the dirt bikes that are now modern racing machine are high-end technology to make a rider comfortable to various track conditions. In all forms of racing "Research and Development" = R&D is very expensive. I too saw the first year of the 4-stroke dirt bike mixed in with 2-strokes in the Super-cross ranks. One rider from Europe raced a Yamaha. What year and the rider escapes me. But it was a very distinct sound compared to the 2-strokes. Yamaha had a 400cc 4-stroke  which was heavy as H3LL up against 250cc 2-strokes in MX back in the day. Dude it just grew from there.

Check out each individual Brand's history. You will learn a lot. There might be a few historians on TT to give a whole lot more input on your Topic. But just to give a hole-in-one comment, it would take all day to write that up if I am reading what you are asking for.  

My Bad.  I was getting numbers mixed up.  It's a 1990 RM125.  It's bored out to 144.  And it was the first year they had the inverted forks.  I don't have a picture of his but I saw the inverted forks.  I hope he pulls it out and fixes it up.  It's in his workshop and has been sitting for a looooooooong time. 

A pic from the net:

13395012705_ae51742cb8_b.jpg

 

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2 hours ago, ah665 said:

Ricky rode the RM250 2 stroke for SX, when he first switched.

Yeah, that's what I saw on the video last night.  They said it was the first time suzuki won any comps in a loooooooong time.  I'm pretty sure it was a 2 stroke 250 along with many others.  But I do think the other guy might've been correct about Windham's bike.  I remember someone dumping it and the announcer guy pointed out how the 4 strokes are harder to get started and take a few moments more than the 2 strokes. 

 

The wildest race of all was this race in Anneheim.  It was not a completely enclosed arena and it rained and it was a mudbog.  Everyone was falling down and getting stuck.  One guys front wheel completely locked up and he was like kicking it trying to get it to move free.  It was ridiculous.  But they all just soldiered on through the whole race. 

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1 hour ago, ah665 said:

Ya I just now noticed that also. Powervalves were on the modern bikes by the 80s. Not sure where the article got the 2005 from.

 

Basically (for the OP) riding a 2stroke that doesn't have a powervalve make the power spread a lot more like a light switch. So 2 strokes that have them have a much better transition from low rpm power to top when it is really screaming. But mlatour gave a very good technical response to how it works.

Well that's good to know that the motocross bikes had them on since the 80's.  Not sure why that article I read said 2005.....   I did understand what they did to make it better thought.  I also watched a husky video that said EFI is making the current 2 strokes way more consistent and more low end power.  A lot better or trail riding than the older 2 strokes.  At least in the Husqvarna models. 

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2 hours ago, Doug. said:

In 2005 that was the FIM World Supercross GP. It was a separate title they had for a few years back then and they ran two or three rounds outside of the US prior to the start of the AMA Supercross series in January. Those who chose to race them were in contention for both series points. In 1999 and 2000 the only four-strokes on a racetrack were Yamaha's, in the 250 class (now 450 class) and they would have been a YZ400F or YZ426F. John Dowd, Jimmy Button, Doug Henry if memory serves correct.

The 2005 SX season was the last that was predominately two-strokes (and won by a two-stroke), and the 2003 MX season was the last that was predominately two-strokes. In 2004 Factory Yamaha and Honda riders began riding four-strokes outdoors but stayed on two-strokes in SX. Suzuki and Kawasaki had a manufacturing partnership in 2004 until 2006 that made the RMZ-250 and KX250F the same bike, going their separate ways in 2007 and building different bikes. 2004 was the first year I remember four-strokes in the 125 class (now 250) although I'm pretty sure Nathan Ramsey or someone was on a CRF250R maybe one year before that. Ivan Tedesco won the title on his KX250F which was brand-new.

Supermoto was four-strokes. Converted YZ450F's and CRF450R's back when it was big and in the X-Games.

Wooooah.  I did not know that about Suzuki and Kawi.  Interesting.  In that video there was a guy that moved up from 125 to 250 named James Stewart who did really well.  He was one of the few on a Kawi.  He was fast.  But he did get hurt and had to sit part of the season out but came back with a vengeance.  But either way, I guess RC was just too consistent for anyone else to beat, even though he wasn't getting firsts during the 2nd half of the season as much.  Or maybe at all....    It showed Jeremy McGrath had returned but wasn't necessarily that much of a contender that year.  Now the race I went to in illinois, I think he won that one.  And Travis Pastrana did well too.   Maybe I can google the seasons and see where it was I was at.  It was out in the middle of nowhere. 

Yep, I was going to say Joliet and make some reference to the Blues Brothers but I wasn't for sure.  My memory is getting..... older.  LOL.  I'm glad it still works kind of... LOL. 

 

 

Route 66 RacewayJolietIllinois2000Racetrack

https://en.wikipedia.org/wiki/AMA_Supercross_Championship

 

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Wow, even better, I remembered who won correctly.  Except Travis was only in the 125 class.  That I had forgotten.  But he won the 125.  Jeremy won the 250. 

I just remember thinking they were in the air more than they were on the ground.  LOL.   Well at least the 250 guys. 

 

https://racerxonline.com/results/2000/joliet/250sx

 

I don't see any of those 3 names of the guys that rode 4 strokes but I'm pretty sure there was 1 or two running. 

 

 

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Lol yes, we know who the guy names James Stewart is. One of the most famous SX racers in the modern age. Also, RC won just about everything he raced in. He wasn't just consistent.... he was also the fastest. He has 15 championships between mx and sx and has won motocross of nations multiple times. Won the ama motocross championship 6 years in a row. Has multiple perfect seasons were he didn't lose 1 moto. His nickname is the GOAT and pretty much no one around the world disputes it.

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