KX Riders
Maintenance & Technical => KX500 Aluminum Frame Conversion (AFC) => Topic started by: tkeen511 on January 01, 2016, 05:44:30 PM
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So after years of studying, saving, planning, searching for a decent blown up bike, and finding the time, I'm finally starting my aluminum frame conversion. The donor bike is a 98 kx 250, whom I've named fokxy cleopatra, and have been in a pretty committed relationship with for about 5 seasons. But it's time for a face lift. I recently purchased a running 2013 kx 250f to use, but then about a month later came upon a deal I couldn't pass up on a 2014 kx 250f which the connecting rod snapped, punched a hole through both cases, and wedged the piston completely sideways inside the cylinder after only 29 hours of use. Huge bummer for the original owner, but a gold mine for a guy like me. Im excited to finally be getting started, I started taking a few bolts off the 14 tonight.
Here's the donor bike
(http://i68.tinypic.com/smy8nl.jpg)
(http://i65.tinypic.com/2mx4wed.jpg)
(http://i66.tinypic.com/35apyed.jpg)
And now the 14.....
(http://i63.tinypic.com/1jcwj.jpg)
(http://i66.tinypic.com/5wb4sl.jpg)
Took off a few bolts
(http://i64.tinypic.com/23nxag.jpg)
Till a few became "only a few left"
(http://i66.tinypic.com/znvoe0.jpg)
(http://i64.tinypic.com/zk391j.jpg)
Finally had the whole thing apart.
(http://i67.tinypic.com/35014z4.jpg)
Here's a 2 stroke kx 250 motor I managed to score on ebay with a completely destroyed bottom end and an irreparable cylinder. Cheap and works perfect for me to use as a Light weight mock up motor while my actual motor will be being rebuilt.
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I also now have an extra 2013 kx 250f frame in good condition, a bunch of extra parts for the 2014 kx 250f(radiators, brain box, all electrical, fuel injector, etc), and would entertain trades of my forks for a set of air forks, and now have a whole rolling chassis for a 98 kx 250, awesome for a cheap kdx conversion or potentially 500 conversion. If anybody's interested in any of that, just let me know.
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how much did you snag the '14 for? always curious to know what guys let them go for that dont want to bother parting them out but know the repair bill is going to be several thousand $.
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how much did you snag the '14 for? always curious to know what guys let them go for that dont want to bother parting them out but know the repair bill is going to be several thousand $.
I paid $1500 for it delivered to my door step. It's not perfect obviously. Could use fork seals, brake pads, tires, the usual. But a lot better deal in the long run. He was either looking at having to buy a completely new motor, or pay service Honda to convert it, and neither were cheap. I don't know how I'd feel about putting a 500 in a fuel injected 250f though. Taking it apart, everything is very very tight and very limited space for EVERYTHING just with the 250f. 500 might be pushing it. The non fuel injected 250fs seem to have some more room.
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thats a killer deal for sure. that frame on ebay would bring 600+ easy.
how far are you planning on taking the conversion with aftermarket parts or is it just more a engine swap?
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Yeah, I bought a 2013 frame for about $500. I was surprised how long the bike actually sat. I plan on taking the bike pretty far. I plan on sending the motor out to Todd at pinnsonault and get the crank rebuilt and balanced, boring the motor out to 295 and possibly porting it, and of course throwing a wossner rod in. I have a lot planned that I want to do to the bike, things to experiment building, nice things to buy, a few tricks up my sleeve. But first thing is first, I have to have the bike running, right? Fancy parts and cool things aren't so fancy and cool if you can only look at them :,( I like a lot of ideas from your build, and was thinking about doing some similar stuff when we get slower at work and I can throw some of my stuff on a machine, but like I said, the goal is to get the bike running and riding, and then do all the fancy gadgets. But I'll think you'll like the finished product :)
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Made some more progress today, nothing exciting for you guys, but pulled the motor out of the 2 stroke. Kinda sad to see her like that, but best for the long run. Anyways, I have some questions, anybody know of a seat cover similar to the one pictured, that would be fit for a more modern seat like mine? I found a purple two two retro seat cover on eBay, like the one chad reed used for the retro night. I'll post pics, it's ok, but not exactly what I'm looking for. And also, I'm not a painting guy, it's all out of my element, but I'd like for my spring to be painted purple, like the rest of my kx's have been. Will powder coating flex like that? Anybody know what the factory uses? Or what the color is called? Hopefully tackle the gas tank this week, convert it for a petcock. May possibly get an oversized tank, anybody know what kind of room there is for an oversized tank? May just go with a kdx petcock since it has reserve. Thanks in advance. - Tommy
(http://i68.tinypic.com/i2kmcm.jpg)
(http://i63.tinypic.com/o5xjjs.jpg)
(http://i68.tinypic.com/9kv80h.jpg)
(http://i65.tinypic.com/5p4g2g.jpg)
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Well I have very slowly been making some progress on the build. Been taking the engine apart on the 2 stroke motor, planning on sending it to sand blaster for some vapor blasting. Also thanks to jbernard I got some sweet frame rails and yoke, so far it looks like everything will fit pretty nicely. I got some cutting done today but it's about -8 F here right now, so I was working in the basement and the compressor didn't have enough juice to power the air tools to cut out the welds, so I'm gonna wait till it warms up a little to work in the garage and get these welds cut out and start doing some tacking.
(http://i64.tinypic.com/o89snb.jpg)
(http://i66.tinypic.com/2ntius1.jpg)
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Those are some great looking parts. Looking forward to seeing them installed. Good Luck with the build.
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Got the chance to grind out the welds today and line everything up. Just gotta machine up some motor mounts, and make some spacers for the swing arm bolt, the 2 stroke engine is skinnier in the back than the 4 stroke, and I'll need to open up the hole on the 2 stroke to fit the swing arm bolt through it. Should be seeing a lot more progress here soon. Sorry that all the pics are crappy, I just have an iPhone and a bunch of film cameras
(http://i63.tinypic.com/mv0xmf.jpg)
(http://i68.tinypic.com/2ldnhy.jpg)
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Don't forget to get hold of some 22 mm offset clamps to make it handle better and some p circuit longer dog legs on the linkage helps as well .
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Don't forget to get hold of some 22 mm offset clamps to make it handle better and some p circuit longer dog legs on the linkage helps as well .
Just curious, why do you say that? On my 13 the wheel base felt short but I only noticed it on the hills when it would want to tip backwards more than a 250 2 stroke or a 450. And I don't ride much wide open desert style riding, only tight and winding single track, so I'd like to still keep its turning ability sharp.
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The 22 mm triple clamps give the bike more trail , so when you lean and turn you have more grip on cornering especially on turn in which the kx 250 f does , so it momentary loses grip when you start to turn and lean , makes it turn better, as for the longer link gives the bike a less stinkbug feel and changes the rising rate so it firms up in the stroke faster , I do this to a lot of kx f bikes except the kx450 16 model as it a very good handling machine and only needs personal set up in the suspension as all bikes need.
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Got some goodies coming in here and there. This one puts a big smile on my face
(http://i63.tinypic.com/28u7o2c.jpg)
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(http://www.patentlyapple.com/.a/6a0120a5580826970c01b7c7dad441970b-800wi)
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(http://i51.photobucket.com/albums/f373/Alexander_Veldman/11518290_zpsigwwrb46.jpg)
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Gotta love when more parts show up right? :mrgreen:
(http://i67.tinypic.com/v8k6ex.jpg)
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Any progress on the build?
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Yeah but not as much as I'd like. I'll post some pics soon
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Well I have very slowly been making some progress on the build. Been taking the engine apart on the 2 stroke motor, planning on sending it to sand blaster for some vapor blasting. Also thanks to jbernard I got some sweet frame rails and yoke, so far it looks like everything will fit pretty nicely. I got some cutting done today but it's about -8 F here right now, so I was working in the basement and the compressor didn't have enough juice to power the air tools to cut out the welds, so I'm gonna wait till it warms up a little to work in the garage and get these welds cut out and start doing some tacking.
(http://i64.tinypic.com/o89snb.jpg)
(http://i66.tinypic.com/2ntius1.jpg)
where did you get those good looking frame rails and Y? I am looking at a 2013 KX250f and thinking about putting a 14 KTM 300 motor in it...
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Those rails were made by jbernard, who is doing the really awesome 500AF conversion on this site. He hasn't been on in a while, but I think he may still have some.
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Those rails were made by jbernard, who is doing the really awesome 500AF conversion on this site. He hasn't been on in a while, but I think he may still have some.
Thanks I will try sending him a message
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Alright guys sorry I haven't posted in a while, but I haven't made much progress. The project started as a 250 2 stroke conversion, but when I came across a nearby complete kx 500 for $250 I really couldn't say no. I bought the bike, and it's been sitting for almost a year. Been hard to find time and funding for it since I moved across the country, and didn't even have any of it with me, and working in the motorcycle industry doesn't exactly help the funding. So anyways, I finally got around to getting the motor on my bench. Still have some fab work to do to the frame but I figured I'd get this started. As i started tearing into the motor I realized it was a little worse shape than I originally thought. Cylinder walls have a little bit of surface rust, connecting rod is pitting, main shaft has some surface rust, I will see what I will clean up. Seems like photobucket has gone down, so I'll give my best attempt at posting from imgur.
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(https://i.imgur.com/ozjuSpL.jpg)
(https://i.imgur.com/eNuwqKY.jpg)
(https://i.imgur.com/C9Y9MD6.jpg)
(https://i.imgur.com/FeWZk7u.jpg)
(https://i.imgur.com/1xkUvSZ.jpg)
(https://i.imgur.com/DdnydkO.jpg)
(https://i.imgur.com/8RztaLC.jpg)
(https://i.imgur.com/4TV2AKh.jpg)
(https://i.imgur.com/5zyNlxK.jpg)
(https://i.imgur.com/6i3CYT0.jpg)
(https://i.imgur.com/0ldkgV5.jpg)
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I fixed your pics.
If you go back and modify your last post you can see how I fixed the pics so that they show up 8-)
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Split the cases tonight, not exactly what i wanted to see. The previous owner said it was his dads bike and he decided to restore it after his dads passing, until finally giving it up and selling it to me. He said he rebuilt the bottom end, obviously every bike on Craigslist has a new bottom end, I took it with a huge grain of salt and figured I'd split the cases anyways. The main shaft had some surface rust on it but it came off ok with just a little bit of scotch brite, so no worries there. However, the main bearings were trash, the right side main bearing came out with the crank, the connecting rod has aluminum that appeared to be molten at some point, and you can see where it shaved the cases and eventually cracked the left side case. Right side appears to be ok, and thankfully the crack appears to be repairable.
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(https://i.imgur.com/ezYIAjK.jpg)
(https://i.imgur.com/ohWnhvi.jpg)
(https://i.imgur.com/PonMDsA.jpg)
(https://i.imgur.com/mXEgxnE.jpg)
(https://i.imgur.com/bg16vsu.jpg)
(https://i.imgur.com/5z9AVxU.jpg)
(https://i.imgur.com/bq2E0zm.jpg)
(https://i.imgur.com/ADuinRb.jpg)
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I fixed your pics.
If you go back and modify your last post you can see how I fixed the pics so that they show up 8-)
Much appreciated. Think I got it figured out now
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Made some more progress during lunch today. Not a whole lot, but better moving forward a little bit than nothing at all. Cleaned up the sub power valves a little bit and started chipping away some of the carbon build up inside the exhaust port. Have plenty more cleaning to do before i start porting it.
(https://i.imgur.com/9Kiq6xV.jpg)
(https://i.imgur.com/6iVHmQh.jpg)
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Since you are right there...
https://www.youtube.com/watch?v=-bxZo7KStGQ&feature=youtu.be (https://www.youtube.com/watch?v=-bxZo7KStGQ&feature=youtu.be)
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Since you are right there...
https://www.youtube.com/watch?v=-bxZo7KStGQ&feature=youtu.be (https://www.youtube.com/watch?v=-bxZo7KStGQ&feature=youtu.be)
Thanks a lot! This thing has never actually ran in my possession, so I'm somewhat oblivious to some of the issues these tend to have, so I'm always looking for anything I can do to make it a better build! Because I will tear it apart 100 times till I have it perfect if I miss something. So thanks for pointing that out. I have plenty of research to do on the internet before i decide exactly what I want to do with it.
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What kind of riding are you going to be doing?
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Mix of everything. Motocross and enduro cross mostly, and I set my bike up very similarly for both. Do a lot of woods riding too but I think I'm gonna set this bike up mostly for mx/ex and then revalve the suspension whenever i decide to ride woods.
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Hey guys, hate to do it but everything from this post is now up for sale! If anybody wants any of it please pm me.