KX Riders
Maintenance & Technical => KX500 Aluminum Frame Conversion (AFC) => Topic started by: Reddy on December 16, 2008, 01:27:31 AM
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I'll apologise before I start - I couldnt find a KX250AF forum :(
I own a 2007 RM139, and have looked at puttnig the engine into an RMZ chassis. That was until at the weekend I was offered a blown up 2007 KXF250 bike for little to no money!
I have also found a KX250 engine, with electrics and carb for decent money, so this is going to be my project this winter.
Does anyone have any advise on where to start?
After reading other threads it looks like the exhaust is the most awkward part of the project. Anyone know of a good exhaust to start with?
Thanks in advance
This is a good place for your post, don't worry about it.
Admin.
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I don't think the pipe will be an issue on a 250/250f conversion, in my opinion the airboot will be the most difficult issue, that is depending on the year of motor, there could be headstay issues as well. nothing that can't be overcome. I may do the same project this winter if I have time, have most of the components already just short time.
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Right ok, the engine i've got doesnt come with an exhaust, so i'll just try and get a standard one.
The engine is 2004, i'm gonna start by getting the swinging arm bolt and then take it from there.
I'll try and take pictures on the way and keep you all updated.
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Picked up my donor chassis this morning.
Engine should be with me by Friday - have a good weekend then to start the work.
(http://www.mack1e.co.uk/KXF/DSC00126.JPG)
(http://www.mack1e.co.uk/KXF/039a_1.JPG)
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Right i stripped the KXf down to the bare basics yesterday so once my engine arrives I can drill it and try to get it centred.
(http://www.mack1e.co.uk/KXF/DSC00131.JPG)
(http://www.mack1e.co.uk/KXF/DSC00132.JPG)
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reddy
- i have built them (KX250AF)
(i need to get some finished photos up)
The key things youll have to address are:
countershaft alignment..both vertvcal and horizontal.
moving the yoke "Y" area of the frame up to clear a 2 stroke exhaust.
engine mounts
headstay and a headstay mount of some design.
the pipe and exhaust ,,but those are fairly easy to modify from a stock KX250 stuff.
radiator clearence of the Y area ,and the several hose barbs relocation
and a few incidentals like a cdi and coil bracket etc.
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none of it is too hard to do, if you are a faricator,
and have a welder , mill or lathe and stuff you need
working out the rads..
is likely the largest challenge
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reddy
- i have built them (KX250AF)
(i need to get some finished photos up)
The key things youll have to address are:
countershaft alignment..both vertvcal and horizontal.
moving the yoke "Y" area of the frame up to clear a 2 stroke exhaust.
engine mounts
headstay and a headstay mount of some design.
the pipe and exhaust ,,but those are fairly easy to modify from a stock KX250 stuff.
radiator clearence of the Y area ,and the several hose barbs relocation
and a few incidentals like a cdi and coil bracket etc.
**********
none of it is too hard to do, if you are a faricator,
and have a welder , mill or lathe and stuff you need
working out the rads..
is likely the largest challenge
With "radiator clearence of the Y area" you mean placing them more to the out side???
Gone look tomorrow again with mine, looks like it's pritty tight around the Y section
for radiator and exhaust to fit both.
Dutchie
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Thanks for the advice, unfortunately i am not a fabricator! But will have a go at most things.
My plan is get the engine mounted through the swinging arm, and then get someone to sort the frame out.
THen the rest will be up to me! I'm looking forward to the challenge though.
Any more info and pics would be great.
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Thanks for the advice, unfortunately i am not a fabricator! But will have a go at most things.
My plan is get the engine mounted through the swinging arm, and then get someone to sort the frame out.
THen the rest will be up to me! I'm looking forward to the challenge though.
It's the same for me Reddy, only I will do the frame a much my self for what I can.
It's funny that we are doing the same at the same time, only 250 vs 500.
Dutch
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Yeah I'm trying to do as much of it myself as well.
Whats even funnier was my plan this winter was to put my RM139 engine into a RMZ frame! never mind, means I can keep that now :)
Still waiting on my engine will update with pics when I get it mounted.
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I was planning to buy a 09 rmz450 or 09 kxf450.
Now it's the kx500af :mrgreen:
Dutch
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Received the engine today, the swinging arm hole is already 17mm and will bolt stright in.
Will post some pics once I get the engine fitted and mounted from the top engine mounting.
I'm excited, and its not for xmas :)
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I've had a few good days on the build, have made the spacers for between the engine and swinging arm.
Also cut the frame to clear the exhaust, in doing do I managed to save the y piece, clean it up and am basing that on the rebuild.
As it finished today I had the engine braced in situ where I want it to sit, also I have the exhaust clamped so I know that is in the right position.
There are still a few problems to solve:-
- Left hand radiator is too long
- Water pump is vey close to frame and need to check it will clear
- spark plug is going to be very close to bottom of the tank
(http://www.mack1e.co.uk/KXF/DSC00147.JPG)
(http://www.mack1e.co.uk/KXF/DSC00148.JPG)
(http://www.mack1e.co.uk/KXF/DSC00149.JPG)
(http://www.mack1e.co.uk/KXF/DSC00150.JPG)
(http://www.mack1e.co.uk/KXF/DSC00151.JPG)
(http://www.mack1e.co.uk/KXF/DSC00152.JPG)
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Image of Y piece after removing the 2 old engine mount holes
(http://www.mack1e.co.uk/KXF/DSC00159.JPG)
(http://www.mack1e.co.uk/KXF/DSC00160.JPG)
First fitting to check if the Y piece will clear the engine (it didnt and we had to cut it 1" below right have rad mount)
(http://www.mack1e.co.uk/KXF/DSC00161.JPG)
(http://www.mack1e.co.uk/KXF/DSC00162.JPG)
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(http://www.mack1e.co.uk/KXF/DSC00163.JPG)
Fitting the Y piece
(http://www.mack1e.co.uk/KXF/DSC00166.JPG)
Final Fitting, all looks good, even clamped the exhaust in situ :)
(http://www.mack1e.co.uk/KXF/DSC00167.JPG)
(http://www.mack1e.co.uk/KXF/DSC00168.JPG)
Picture from the rear - chain alignment and exhaust position perfect :)
(http://www.mack1e.co.uk/KXF/DSC00169.JPG)
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Clearance for the left hand drop.
(http://www.mack1e.co.uk/KXF/DSC00173.JPG)
I got excited and had to put the tank andplastics back on.
(http://www.mack1e.co.uk/KXF/DSC00174.JPG)
(http://www.mack1e.co.uk/KXF/DSC00175.JPG)
(http://www.mack1e.co.uk/KXF/DSC00176.JPG)
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So the plan for the next week is to get some ali plate and tube to make the engine brackets, exhaust brackets and connect the Y piece down to frame.
Once they are made it can be sent off to be welded!
Does anyone have any ideas on what radiator I can use on the left hand side? Or is it possible to get one shortened?
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reddy,
i only have some old ,*starting the project* shots..
i need to get some of a completed KX250AF up.
I use a 09 KX250 yoke,,,
(similar to what you're using though)
here is the first mock up of the frame..
the radiators - yeah way tougher than the frame..
i ended up modding the lower tanks to clear the raised Y area..
tossed the left rad altogether, and used a right rad on the left side,,
flipped it over, then modified the tanks..(getting rid of the rad cap spigot) and added new hose barbs accordingly
there's a million different ways to skin a cat though..
you'll get it.
(http://i137.photobucket.com/albums/q203/aj277/KX250AF/kx250af5.jpg)
(http://i137.photobucket.com/albums/q203/aj277/KX250AF/kx250af3.jpg)
(http://i137.photobucket.com/albums/q203/aj277/KX250AF/kx250af2.jpg)
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Image of Y piece after removing the 2 old engine mount holes
(http://www.mack1e.co.uk/KXF/DSC00159.JPG)
(http://www.mack1e.co.uk/KXF/DSC00160.JPG)
Did you just removed the old the 2 holes??
Or have you weldid a small strip in/on???
I thought it would be hollow.Maybe it could work for me also!!
Good works man.
Dutchie
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Just cut through it with a hacksaw straight through the 2 holes, and then filed and polished the surface, about 20 mins work all in all. Looks good, and gave me the extra bit of room I needed to clear the engine.
Only had an hour on it today, made the 2 bottom engine mounts.
Need to get the ali tube now, think i'm going for inch square with 2mm wall thickness.
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25x25mm and 2mm thick is stock!!!! Should be good than.
Tomorrow I'll start working again, so I can go further with it.
And give some pics and info again.
Dutch
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Just wondering if you guys bend the ali tube?
Just I need to connect the Y piece down to the original frame and thee is a bend at the end.
Any ideas would be good.
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I'm planning to make mine own bender. With this as an example.
http://mittlerbros.com/tube_bender_180_hand.htm (http://mittlerbros.com/tube_bender_180_hand.htm)
And buy 6 metre alu tube to try :-D
Whow is gone weld your bike??
dutchie
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Thats like th tool i was gonna try and build!
But i dont know how well it will work.
Got a local Ali welder that races local to me, so he's gonna do it all :)
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Welllllllllllllll.................To be honest I didn't found that link, is't JFAB's :oops:
But hat more or less the same idea, only wasn't sure if it could work.
I think to go to a old famely friend(JBR SERVICE) for the welds.
When you see al of those 500's over here. Don't you whant it also than???
Or is that the next step??? :-D :-D
dutch
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Sorry about the delay guys! But my bike is now ready to be welded (pics uploaded soon)
I;ve done a fair bit of work, but it now looks like a bike again.
I've bought a set of Honda CR250 radiators, as I cant find anyone to shorten my KXF rads, and to have a set made was gonna cost me ?380! So i'm hoping the honda rads will fit with a mounting bracket.
Once I get it back, it can be stripped, greased/cleaned/polished and then assembled!
Just hoping to get something sorted with the airbox and radiator hoses now :cry:
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At las tonight i am having my frame welded! Its been a long time coming, mainly been waiting the the ali welder!
Once its done will post some pics of the bike, and take loads of pics as I build it up for the last time :)
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Its not quite finished, only a few hours left though.
(http://www.mack1e.co.uk/KXF1.JPG)
(http://www.mack1e.co.uk/KXF2.JPG)
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OK so I finished my bike on Sunday afternoon and raced on on the Monday! First time racing a 250 2 stroke and I loved it.
Here are some pics
(http://www.mack1e.co.uk/finished/2.jpg)
(http://www.mack1e.co.uk/finished/3.jpg)
(http://www.mack1e.co.uk/finished/4.jpg)
(http://www.mack1e.co.uk/finished/5.jpg)
(http://www.mack1e.co.uk/finished/6.jpg)
(http://www.mack1e.co.uk/finished/7.jpg)
(http://www.mack1e.co.uk/finished/8.jpg)
(http://www.mack1e.co.uk/finished/9.jpg)
(http://www.mack1e.co.uk/finished/10.jpg)
(http://www.mack1e.co.uk/finished/11.jpg)
(http://www.mack1e.co.uk/finished/12.jpg)
(http://www.mack1e.co.uk/finished/13.jpg)
(http://www.mack1e.co.uk/finished/14.jpg)
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Very good write up, pictures on the mark, quality build. A+. Nothing like a bike built with your own hands. Does it count that I bolted all the aftermarket stuff on the bike AJ built for me?
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Real Beauty Reddy!!! The black numberplates with green backgrounds looks fantastic!!!!!!
Congrats on your Ride!!!!!
Dutch
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Real Beauty Reddy!!! The black numberplates with green backgrounds looks fantastic!!!!!!
Congrats on your Ride!!!!!
Dutch
Cheers, took just under 4 months start to finish. Had good comments at the meeting weekend just gone, helped by a 5th overall first time out :)
I know there is a lot of experience on this forum, but any questions just ask, i've prob got a picture of it!!
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I'm planning to make mine own bender. With this as an example.
http://mittlerbros.com/tube_bender_180_hand.htm (http://mittlerbros.com/tube_bender_180_hand.htm)
And buy 6 metre alu tube to try :-D
Whow is gone weld your bike??
dutchie
http://jd2.com/ (http://jd2.com/) has a real good bender.
http://www.gottrikes.com/Tube_Bender.htm (http://www.gottrikes.com/Tube_Bender.htm) has plans for building your own.
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I am about to start conversion this weekend. I blew up my 06 450 for the second and last time a week ago. I found a 06 kx250 motor and electronics, and have ordered new exhaust, ect.... hopefully done within a couple of weeks
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nice job, the bike looks great!!!
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bike should be good to go for this weekend....06 KXF450 chassis, 06 KX250 powerplant.....looking forward to riding a smoker again(and not blowing up antoher 4 stroke)
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lol hogie-
at ran good ,and you rode it pretty dang well too!
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lol hogie-
at ran good ,and you rode it pretty dang well too!
all thanks to you AJ, you are the master!