500 two strokes in original frame vs modern frame?

ML512
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Wildomar, CA US
Fantasy
Edited Date/Time 2/26/2022 7:20am
This video from AJ Catanzaro comparing a CR500 in its original frame vs a modern KTM chassis with a KX500 had me curious what others experiences were like?

My only 500 conversion experience was a KX500 motor in a KXF aluminum frame back in like 2011 or 2012-ish...and honestly, I hated it. Laughing

Anyone else here been able to dabble in both experiences? Are frame conversions for a 500 over rated?



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kott0n
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2/23/2022 7:14am
I love mine. It absolutely rips. You only feel the vibration when sitting still and who does that?

Its an older one at this point, a 2006 CRF250R with a 1989 CR500 motor.

Amazing low end torque, great handling, its very lightweight.
4
2/23/2022 7:17am
Conversion in a modern steel is GREAT. an AF is ok, but only because of the cost and emotional involvement. My '14 SH was good, but not worth the cost. 01 Maico is better.
KurtJ99
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2/23/2022 7:32am
I have a 2008 Service Honda CR500AF. I used to race ‘85-‘89 CR500 and the AL frames is better with modern suspension. However it doesn’t seem to corner ruts as well when I hope back on a steelie for comparison. I spend a lot of time on spring/sag/fork height getting it acceptable. I missed out on a NOS RG3 linkage that was supposed to improve cornering in that model year.
For a Vet race bike I think the AF is better. But the older I get I’m sure the less it will matter.
Vibration is fine but it’s not a four stroke. Just keep crank bearings fresh, exhaust flange seal and headset tight and your fine.
3
sende
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2/23/2022 8:15am
They mentioned this man on the video and I checked his channel.
Now that is a bike collection.


4

The Shop

yota
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2/23/2022 12:10pm
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a fan of the KX500 motor compared to the CR500 but many would disagree with this. the CR500 engine does not need a power valve. it has plenty of low end and power everywhere.

bought my 94 in 2009, rode it for a few months in the original configuration to make sure the engine and bottom end were good. it handled surprisingly good, but my use has only been florida off road riding. haven't moto'd for decades.

had a guy in Southern Cal do the frame mod and then I put it all together. the guy did some awesome fabrications but was flaky and ended up ripping a lot of people off.

my conversion was done on a 2003 CR125 chassis. It handles well but you always feel the engine gyro effect no matter what frame the engine is in. they do vibrate but I don't really notice it while riding. sitting and idling, it is very apparent.

as far as suspension I have ohlins TTX front and rear. works well for off road. in the rear I' m using a titanium spring from a YZ 450F. ohlins TTX and YZ shock springs are interchangeable. not sure about the newer stuff.

a few rides ago I installed a recluse auto clutch. don't really see the need for one of these on my other bikes but when you're racing your bud's thru the woods and you stall going over a log or something having to use the starting "drill" leaves you all by yourself in a few seconds. I'm 155 lbs and 68 years old so just kicking the bike to start it real quick isn't an option. some guys go with a compression release in the head.

the bike has the most low end response I've ever experienced, and I've had a couple of 450's. I ride mostly in the sand or I think I would have killed myself by now. I had to stop riding for 4 years due to a health issue and just started again about 8 or 9 months ago. this bike was my every sunday ride before I quit. about 6 weeks ago, I took it out again for the 1st time in years and busted my ass. bounced off a small stump or something lost hold of my left grip and whisky throttled. that is a really bad experience on a 500 2 stroke. by the time I could bail it was going fast and I took about a 6 foot drop off an embankment onto my tail bone. still freaking hurts. first time since 2009 that I felt out of control on this thing.

1st pic is how I found it on Craig's in north miami in 2009.









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yota
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2/23/2022 12:13pm







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yota
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2/23/2022 12:15pm
the modified 125 alum frame actually weighs 1 lb more than the steel frame.




4
cmotodad
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2/23/2022 12:41pm Edited Date/Time 2/23/2022 12:43pm
I have built 5 different framed CR500 and KX500 bikes. 1 in a 125 frame, 1 in a crf250 frame 2 in cr250 frames and a KX 500 in a steel 250f frame. The newer the crank bearings, the less vibration but still more than a stock frame, IMO. All the Hondas felt good but I really liked the 125 chassis. For me, the best is the 2004 KX250F steel framed bike. Less vibration than the AL,s but with the modern ergos, I could go from 2 to4 stroke with minimal effort. Raced the CR500 at the Vet World one year and ended up on the top step of an old guy expert class. Harder than a 250 but so much fun having raced big bore 500's back in the day. Compared to new 4 stroke,they are definitely an acquired taste.
4
sandman768
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2/23/2022 12:42pm
yota wrote:
the modified 125 alum frame actually weighs 1 lb more than the steel frame. [img]https://p.vitalmx.com/photos/forums/2022/02/23/535143/s1200_94CR500frame002.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2022/02/23/535144/s1200_TTMCR5001stday010.jpg[/img]
the modified 125 alum frame actually weighs 1 lb more than the steel frame.




Awesome build!
3
cmotodad
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2/23/2022 12:50pm
Yota, do you recall the socal guy that did the frame? Were the intitials PS? I did all my own and you are right, getting the motor in with no bind is so important. Also, when you tightenn it up, raise it inn the middle of the mounts and not let it rest on the bottom of the bolts. I think being in your 60's ( 65), you enjoy the old big bores even more.
1
cable
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2/23/2022 12:53pm
I rode them back to back way back in 2001. expert/pro level. Turning was huge difference. 500s, are hard to slow down and were hard to get to inside lines, back in the 2 stroke days. could probably get a steel to turn better with clamps. On smooth days you could smoke a 250 easily. rough days the 2nd motos were tough.
2/23/2022 1:11pm
I bet his first name was Mike who discovered meth and ruined his business and life. He had some nice work early on.
1
philG
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2/23/2022 1:56pm
Its a good way to halve the value of 2 bikes.

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Magoofan
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2/23/2022 2:01pm Edited Date/Time 2/23/2022 2:02pm
I have nothing to add here other than copious amounts of drool over Yotas pics.....
4
kott0n
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2/23/2022 2:22pm
yota wrote:
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a...
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a fan of the KX500 motor compared to the CR500 but many would disagree with this. the CR500 engine does not need a power valve. it has plenty of low end and power everywhere.

bought my 94 in 2009, rode it for a few months in the original configuration to make sure the engine and bottom end were good. it handled surprisingly good, but my use has only been florida off road riding. haven't moto'd for decades.

had a guy in Southern Cal do the frame mod and then I put it all together. the guy did some awesome fabrications but was flaky and ended up ripping a lot of people off.

my conversion was done on a 2003 CR125 chassis. It handles well but you always feel the engine gyro effect no matter what frame the engine is in. they do vibrate but I don't really notice it while riding. sitting and idling, it is very apparent.

as far as suspension I have ohlins TTX front and rear. works well for off road. in the rear I' m using a titanium spring from a YZ 450F. ohlins TTX and YZ shock springs are interchangeable. not sure about the newer stuff.

a few rides ago I installed a recluse auto clutch. don't really see the need for one of these on my other bikes but when you're racing your bud's thru the woods and you stall going over a log or something having to use the starting "drill" leaves you all by yourself in a few seconds. I'm 155 lbs and 68 years old so just kicking the bike to start it real quick isn't an option. some guys go with a compression release in the head.

the bike has the most low end response I've ever experienced, and I've had a couple of 450's. I ride mostly in the sand or I think I would have killed myself by now. I had to stop riding for 4 years due to a health issue and just started again about 8 or 9 months ago. this bike was my every sunday ride before I quit. about 6 weeks ago, I took it out again for the 1st time in years and busted my ass. bounced off a small stump or something lost hold of my left grip and whisky throttled. that is a really bad experience on a 500 2 stroke. by the time I could bail it was going fast and I took about a 6 foot drop off an embankment onto my tail bone. still freaking hurts. first time since 2009 that I felt out of control on this thing.

1st pic is how I found it on Craig's in north miami in 2009.









Surprised you need to do the "starting drill" when its warm.

Mine will fire up with a half- hearted kick just like a 250 when its warm.

Is for sure one of the best motors ever made though. Want to lug it around and take it easy? It will do it. Want to ride it like you are next years supercross champ? It will do it. So versatile and yeah, power everywhere. Will power wheelie in nearly any gear at any speed with a blip.
1
toomanykaws
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2/23/2022 2:41pm
I had a new 06 450f in the crate. Put it together. Rode it 10 hours. Really liked the bike. Didn’t care for the engine especially being a 4 speed. Sold the engine for a good amount. Bought two kx500s for $2000. And built the AF and restored the team green desert 500. Have had as many as six steel frame 500s at one time. Sold a few. One went to France the other Australia. Have two steel frames I can ride for desert. The AF for vet track use. And another steel frame that’s new never been used. 04.

11
yota
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2/23/2022 2:41pm
cmotodad wrote:
Yota, do you recall the socal guy that did the frame? Were the intitials PS? I did all my own and you are right, getting the...
Yota, do you recall the socal guy that did the frame? Were the intitials PS? I did all my own and you are right, getting the motor in with no bind is so important. Also, when you tightenn it up, raise it inn the middle of the mounts and not let it rest on the bottom of the bolts. I think being in your 60's ( 65), you enjoy the old big bores even more.
no, the guys 1st name was Mike. ended up becoming a crack head from what I heard and screwed a lot of guys. his dad owned a machine shop and did a lot of defense dept fabrication. I don't think Mike did the work but he had some talented fabricators and welders. the final touch was a heat treatment of the entire frame followed by a salt spray cooling. this is what the frame looked like from the salt spray when I got it. He was supposed to send it with a cleaned and brushed finish but as he was flaking out on everyone so I asked him to send it as was and let me brush it out. the only reason I didn't get screwed is that he liked me for some reason. the delays took months and I would call him almost every week and talk to him. at least he took my calls LOL. I washed the frame with a very mild acid and brushed it out with a stainless steel wire brush.

3
yota
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2/23/2022 2:42pm Edited Date/Time 2/23/2022 2:45pm
I bet his first name was Mike who discovered meth and ruined his business and life. He had some nice work early on.
yup. but I've never seen a better conversion.
2
yota
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2/23/2022 2:52pm
yota wrote:
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a...
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a fan of the KX500 motor compared to the CR500 but many would disagree with this. the CR500 engine does not need a power valve. it has plenty of low end and power everywhere.

bought my 94 in 2009, rode it for a few months in the original configuration to make sure the engine and bottom end were good. it handled surprisingly good, but my use has only been florida off road riding. haven't moto'd for decades.

had a guy in Southern Cal do the frame mod and then I put it all together. the guy did some awesome fabrications but was flaky and ended up ripping a lot of people off.

my conversion was done on a 2003 CR125 chassis. It handles well but you always feel the engine gyro effect no matter what frame the engine is in. they do vibrate but I don't really notice it while riding. sitting and idling, it is very apparent.

as far as suspension I have ohlins TTX front and rear. works well for off road. in the rear I' m using a titanium spring from a YZ 450F. ohlins TTX and YZ shock springs are interchangeable. not sure about the newer stuff.

a few rides ago I installed a recluse auto clutch. don't really see the need for one of these on my other bikes but when you're racing your bud's thru the woods and you stall going over a log or something having to use the starting "drill" leaves you all by yourself in a few seconds. I'm 155 lbs and 68 years old so just kicking the bike to start it real quick isn't an option. some guys go with a compression release in the head.

the bike has the most low end response I've ever experienced, and I've had a couple of 450's. I ride mostly in the sand or I think I would have killed myself by now. I had to stop riding for 4 years due to a health issue and just started again about 8 or 9 months ago. this bike was my every sunday ride before I quit. about 6 weeks ago, I took it out again for the 1st time in years and busted my ass. bounced off a small stump or something lost hold of my left grip and whisky throttled. that is a really bad experience on a 500 2 stroke. by the time I could bail it was going fast and I took about a 6 foot drop off an embankment onto my tail bone. still freaking hurts. first time since 2009 that I felt out of control on this thing.

1st pic is how I found it on Craig's in north miami in 2009.









kott0n wrote:
Surprised you need to do the "starting drill" when its warm. Mine will fire up with a half- hearted kick just like a 250 when its...
Surprised you need to do the "starting drill" when its warm.

Mine will fire up with a half- hearted kick just like a 250 when its warm.

Is for sure one of the best motors ever made though. Want to lug it around and take it easy? It will do it. Want to ride it like you are next years supercross champ? It will do it. So versatile and yeah, power everywhere. Will power wheelie in nearly any gear at any speed with a blip.
stock CR500 cylinders (as least the last gen) had "dimples" in the bore that eased compression for starting. I sent this cylinder to Millenium to get it back to standard bore (I had them use a steel liner) and lost those dimples plus I weigh nothing. the bike starts easy when I use the drill but it takes a few seconds and by then everyone is gone. the drill is push the kicker down slightly until you feel TDC, let it back up and then push it through firmly. usually starts on the first kick when I do that.
1
pacman00
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Corona, CA US
2/23/2022 2:56pm
I'd run at least the xc gear bar clamp. That's the difference mxa noticed in vibration from the honda to the kx engine. Same chassis.
1
yak651
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Fantasy
2/23/2022 3:11pm
sende wrote:
They mentioned this man on the video and I checked his channel. Now that is a bike collection. [embed][/embed]
They mentioned this man on the video and I checked his channel.
Now that is a bike collection.


Holy Fu#$ who is this guy?! This is what my garage would look like if I won the lottery, unbelievable!
3
2/23/2022 3:45pm
My experience with the 500AF concept goes back to the pioneering days of the first Service Hondas. I ordered an '01 version in what was probably their first full year of building the bikes, so it used the Gen 2 Honda 250 frame and a brand new, off the shelve CR 500 motor. By the standards of the time, it was a very nice product with excellent build quality. Unfortunately, I think the second gen frame was still too stiff for the concept, and the tighter layout made the handling a challenge. Having raced 500 2S's since '86, I ultimately became to the conclusion that the steel frames offered a better overall fit for the big bore engines. I still have the bike and take it to the track a couple times every year just so I can get my ya-ya's out. Any gear wheelies are the standard, and if it doesn't get the holeshot, it wasn't the bike's fault...


1
Kawboy14!
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2/23/2022 5:09pm
Got to ride an old cr500 recently that was cherry! Man that thing was junk compared to my new 450
2
Adam43
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WF
2/23/2022 6:32pm
A stock KX500 with newer forks (SSS or PSF-1) works better on the track than any AF 500 conversion. Particularly if they are built by a hacker.
2
Big Lenny
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Compton, CA US
2/23/2022 8:57pm
yota wrote:
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a...
as you know, set up is everything and equally important is who did the frame mods and how they went about it. I'm also not a fan of the KX500 motor compared to the CR500 but many would disagree with this. the CR500 engine does not need a power valve. it has plenty of low end and power everywhere.

bought my 94 in 2009, rode it for a few months in the original configuration to make sure the engine and bottom end were good. it handled surprisingly good, but my use has only been florida off road riding. haven't moto'd for decades.

had a guy in Southern Cal do the frame mod and then I put it all together. the guy did some awesome fabrications but was flaky and ended up ripping a lot of people off.

my conversion was done on a 2003 CR125 chassis. It handles well but you always feel the engine gyro effect no matter what frame the engine is in. they do vibrate but I don't really notice it while riding. sitting and idling, it is very apparent.

as far as suspension I have ohlins TTX front and rear. works well for off road. in the rear I' m using a titanium spring from a YZ 450F. ohlins TTX and YZ shock springs are interchangeable. not sure about the newer stuff.

a few rides ago I installed a recluse auto clutch. don't really see the need for one of these on my other bikes but when you're racing your bud's thru the woods and you stall going over a log or something having to use the starting "drill" leaves you all by yourself in a few seconds. I'm 155 lbs and 68 years old so just kicking the bike to start it real quick isn't an option. some guys go with a compression release in the head.

the bike has the most low end response I've ever experienced, and I've had a couple of 450's. I ride mostly in the sand or I think I would have killed myself by now. I had to stop riding for 4 years due to a health issue and just started again about 8 or 9 months ago. this bike was my every sunday ride before I quit. about 6 weeks ago, I took it out again for the 1st time in years and busted my ass. bounced off a small stump or something lost hold of my left grip and whisky throttled. that is a really bad experience on a 500 2 stroke. by the time I could bail it was going fast and I took about a 6 foot drop off an embankment onto my tail bone. still freaking hurts. first time since 2009 that I felt out of control on this thing.

1st pic is how I found it on Craig's in north miami in 2009.









Nice...
Big Lenny
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2/23/2022 9:08pm




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1
Gravel
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2/24/2022 9:46pm
I rode KX500s from the late 80s through the late 90s, had a bunch of rides on CR500s with steel frames. Years later I got a 15 minute ride on a converted CR in a mid 2000s frame, I don’t know exactly what. The AF turned better but I didn’t like it. Higher speed stability was terrible and the vibration was worse than I remembered from any of my KXs. Might have been a bad setup for me, IDK..

The KX motor in a linked KTM frame might be the right answer!

Loved the video of the CR vs the KX/KTM, watching them go decent speed while sounding like they were idling around the track brought back a lot of memories. Using the 500 grunt off idle was coolest thing to learn, made it so one gear could do 15 to 45 mph..
1
Tumic
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Sundsvall SE
2/25/2022 1:22pm
My dad owns a couple of Cr500’s. One is a -03 cr250 frame conversion.

I like the more modern feel of the AF bikes, the older steel frames flex to much and don’t support the modern riding style as much as the AF does.

Going back to the 97-99 cr250 when the first gen aluminium frame came to production, many hated it because it felt stiff, but i get the same feeling riding old steel frames that flex way to much.
CPR
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AU
2/25/2022 5:05pm
How sweet would a counter balanced and injected 500 2t be in a modern chassis?
We can dream…….
1
kott0n
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Vancouver, WA US
2/25/2022 5:13pm
2 stroke development has all but stagnated. The FI bikes have a very flat power curve, nothing like the 2 stroke "hit" people love but I'm glad it got developed as it is progress.

Look at the Honda ARC technology for where it was headed before the silly rule changes.

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