KX450F vs. KX500

[USMC 500]

I'm the new guy here but what the hell, with my countless years on both 2 and 4 strokes I'll put in my $2.02 cents in.  

Maintinence wise there is a quantum leap in cost. Two strokes are way cheaper to maintain than NEWER 4 strokes.  Todays 4 strokes are aimed at the factory sx/mx racers who have mechanics who are paid big bucks to tear down the bike and rebuild it every race.  Mr. and Mrs. "don't know squat about bike mechanics" are gonna give 3 mortgage payments to have maintanence done on all the families bikes by qualified techs.  On the other hand I've owned and raced old XR600's, the old KLX650 (the one that came out in 93 and weighed 3 tons), and a DR350 for a short time that I almost never had to touch.  Older 4strokes would last forever with almost no maintanence as long as there were no big engine mods made (remember the Honda XR680 they built for the 1992 baja 1000 to compete with big green? That bike ate itself from the inside out to death).  But those older 4 strokes were aimed at the families out for trail riding fun.  MX, SX, Desert, Enduro, GP's, etc, were dominated by 2 strokes, with the exception of Scott Summers' XR600.  But there is a good example, Scotts XR motor was in virtually stock form and would last through an atom bomb explosion. 

  Then a few events took place.  Team Green pulled out of Baja due to the death of my good friend Danny Hamel and Honda began to dominate the great race which also inspired the birth of the new and improved XR650.  Yamaha built a prototype YZM400 for a young man named Doug Henry to compete with in the SX/MX series.  Many factors such as our good friends the EPA forced the evolution of the 4 stroke.  The factories looked to the future and dumped large amounts of cash into the development of COMPETATIVE 4 strokes leaving less money for the development of the 2 stroke.  However that development like I said is aimed at the large factory racers.  And for those of us who want the great handleing advanced machines that our factory hero's ride then we had better be prepared to fork out the cash to pay the "4 stroke overhead".  But don't fear, if you want a good 4 stroke trail bike for the family that is very maintenance cost effective, Honda still makes their low maintenance XR50, 70, 80, 100, 250, and 650.  Kawasaki makes its KLX 110, 125, 300.  I'm not gonna list all the other factories that make effective family trail bikes but you get the picture.  Thats why older 2 strokes are so fun.  The cost of maintenance is reasonable, and if built right and maintained right (two strokes are sooooo easy to work on by the average schmuck like me), you can have a good handling bike with tons of power that will last you till Y3K.  Thats my opinion which is why I have an older 97 CR250, 98 KX500, and my wifes 99 KX80.  These bikes are low cost to maintain and they have plenty of grunt.

[The Flyin Hawaiian]

I say it depends on the conditions and rider skill. Back in 2000 at a local enduro, I came out of a short tight section onto a sandy two tracker. My friend, who is an A class rider, was on a 99 YZ400F and I, also an A rider, was on a 00 YZ125. Because we came out of the section late, we both were trying to make up time on the dirt road. He got a little jump on me, but I ended up catching and passing him. He weighs about 150lbs and I was about 200. He was in the middle, where the sand was loose and I worked my way up onto the loamier shoulder. I simply hooked up better. I didnt pass him like he was standing still, but I passed him.

[1CrazedKawi]

I'll be honest, I didn't read all the posts, so if I repeat something already said, I apologize in advance.

I own both bikes, and it is apple and oranges. Get a Fofiddy and keep your K5!

Both my babies offer something that the other can not provide.

In a nut shell:

I take both bikes anywhere, (trails,double,and singletracks), but the KX450F has more finesse, and the K5 has more "Raw".

"4-stroke stall, blah,blah,blah........K5 squirrelly, blah,blah,blah" comments are correct.

But that's why I love them both! - After I short while you learn to not stall the Fofiddy and handle the K5. I love them both and wish everybody could own them!!

Go Team Green!!

[KXcam22]

I found another area where the KX500 is clearly superior.....changing the fork oil.  The KX you simply pour it out and pour in the new stuff.  My 450 with the dual chamber forks require complete disassembly, a few special tools, a tech manual and ...some luck. Cam.

[KXcam22]

Actually it is not too bad.  I had to make a 50mm wrench for the fork cap only to find I could have undone it by hand. The rest was more involved than the KX but actually easy.  Dual chambers are cool since you can run different oil in each for better action. Cam.

[tharden]

I just got a hold of a 04 yz450 and I must say it is a pretty sweat ride.  It starts easy hot or cold with effortless kicking of the starter.  It handles well in real tight turns and has good pour on power.  The questing is it my new favorite?   No.  I can take my 500 and still do circles around it.  The 500 just has uncompromisable power that the 450 just can not spit out.  My brother rode the 450 and I lapped him twice.  I can say the 450 does not vibrate as much as the 500, but I am not bothered by a little vibration.

[azracer19]

I feel like a nervous wreck after that DEBATE? anyway I have been trying to decide wheather to build / buy a KX 500 AF... I own a KX 500 now. For the past month our so I have been hitting the local MX track on my brothers RMZ 450. I much rather ride the open desert / race thru the dust hills long sandwashes and the occasional WFO straights. I have been riding many years on the KX 500s some 250s and now the RMZ 450. I weigh in at 165. With experiance in desert races there isnt ANY 450F that will keep up with My 500  ( as long as i can keep up my stamina) . BUT put a 500 on a track or a coarse that requires more then speed the 450F will put the 500 in its place ( the desert ). Now if i was younger and could hold the 500 open for 2 hours I know the 450 wouldnt stand a chance. One thing I did notice is that the 450 takes less effort to ride then the 500, but like earlier stated ( I think ) your dealing with 20 year old suspension versus state of the art suspension. SO IMO the 500 has its place and the 450 has its place. I dont have a clue about an AF 500 in the desert our track but it would be interesting for a non bias shoot out. Just think if the factories ( some of them ) and the AMA didnt kill the 500 what would a 500 be today with all the money and technollogy spent on producing the NEW 4ts. hats off to SH and others that have built an AF 500 , but im sure it could be done better with the right rake/trail...seat height....wheel base....clearance on and on and on....not saying your Afs arent awesome because they are but if done with all the math and proper configuration of building a new bike I am pretty sure it could be built better and probaly would be untouchable in any condition. I myself have never built a bike like you guys are doing to the AF but my dad built us one of a kind race bikes when we were alot younger, the frames were made by a company called VAN-TECH and different parts and engines were used off of all kinds of bikes. I know alot went into building these bikes as it took 2 years to buid one bike...probaly makes no sense........  but ride the hell outa what you have and have fun and fight to keep our riding areas open..

[Uzi9mm]

The 500s and 2-strokes in general weren't killed because of the EPA, they were killed because of greed.   

http://twostrokemotocross.com/2008/10/mxa-shootout-crf450-versus-cr500/

http://twostrokemotocross.com/2009/04/the-epa-vs-motocross/

[azracer19]

your right it wasnt only the EPA  like I mentioned it was some of the factories....Yamaha..Suzuki ( roger decoster ) etc. Some of the best supercross racers ever, rode 500s and were very fast on them....jeff ward...kiedrowski...stanton..... just to name a few but it is what it is  an i think the 450s do have a place there awesome on a track, someone early said to stay out of the rev limiter.....I dont know how that is done because riding the RMZ I was alway on it and the other 450s around me were also, so I can see were maintaince becomes an issue. For those of us ( not me ) who are young enough to make money or at the least get free riding gear and parts its worth it, for the guy having fun I can see why the 2t is better for MX. For me I will borrow the RMZ when iI want to stay competive and ride my 125 KX to have fun on the MX track  and will never part with the 500 for a day in the desert...still somehow  I have to ride AN AF..a guy can dream

[Uzi9mm]

If the info in the EPA vs Motocross article is correct, it says the EPA has nothing to do with regulating 2-cycle engines.  In other words, its all the manufacturers and the AMAs corruption.  Pretty sad but typical.

[azracer19]

well we do see a slew of KTM 2Ts   make you wonder

[dsrtrider]

Lets say there was a parallel universe where 2 strokes (250 and 500) were still around and there were no 4 strokes.  The 500 would have had all the same changes and would be "modern" similar to a 500 AF.  Along comes someone who trys to sell the idea of a 450 fourstroke and says main reason is it has alittel more power and torque than a 250 2 stroke but is heavier, more parts, not a "do it yourself" maintenacne, expensive, etc.  I dont think anyone would be interested.  Their argument maybe that a 500 has to much pwer and a 250 not enough.  I think the logic would be to pursue a 300 2 stroke.  more power and all the benefits of a 2 stroke (ease to maintain, cheaper, lighter, etc).   Sadly this was not the case

Ktm make a 300 2 stroke (offroad not motocross) and it competes very well with the offroad 4 strokes.  If they made a 300 sx it would be competitive with the 450 motocrossers.

The above senario would have been what i think would have been a logical progression but as it happened the 500's were doomed once the nationals ended and they stopped changing them so when the modern 450's came along to fill the need for more power/torque on the 250's and the consumer went with them and now we have heavier, more expensive, hard to maintain bikes.  as you can tell i am a 2 stroke fan.  4 strokes never made sense and i still scratch my head how we let this happen.
i have a kx500 for desert and dunes and a ktm300 for desert racing.  i will continue to supprt companies that make 2 strokes for as long as i can.

[93KX5Rider]

I must agree that the change in the direction of dirtbike/motocross engines was purely out of greed and not because either machine performs better. Look at the world we live in today.

[J.ellwanger]

soo... just curious why don't we all (every active member on this site) pitch in and open our own American MX/Enduro/motard Company??   and just BLOW everyone out the water?!?(mud hole?) 

 Seems like we have a few smart people around, Design. Few dumb but very good riders willing to try anything put their legs, no matter the size of engine, frame, (and by dumb, i mean Crazy guys willing to go outside the norm, where they can and will get hurt, Purposely,) yep i consider my self dumb, cause i know better, but dont care. take the K5 base, kx250 bored as big as we can and improve it, get a guy to practice on it 24/7 and throw him in a race... boom we have spotlight,
  american built Direct injection 2smoker, or maybe make the 300 being mentioned, and Squamp out the 450 4s.?
just a random ??  id be willing to donate all my spare time! as i have nothing better to do with this life I live

[jBernard]

a 300-400cc 2 stroke and for a dream, add in EFI or Direct Injection and IMHO that would be a 4 stroke killer.
the longer the big manufacturers wait the less likely they are going to re-tool and dump money in R&D for 2 stroke.
Unfortunetly it will never happen due to the money made off 4 Strokes, bikes are more expensive, parts are more expensive. why would they go back?

i'm surprised you dont see a 300SX ktm. of course theres the 300XC but have to dump $$$ to convert it to an SX and loose some of the weight. theres also the big bore kit for the 250 but its $$$ as well.
i just bought a '14 ktm 250sx and its awesome. an ultralight 300 would be even better and close the gap the 450 4 stroke has. i dont think they want to make it because it would hurt 4 stroke sales obviously.

and the idea of a private company coming up with a dream engine. i dont think it will ever happen, theres no way someone can jump in and match any kind of R&D ktm or the japanese have come up with. would probably be a 300 2 stroke that put 40hp to the wheels and was full of problems.