KX Riders
Maintenance & Technical => KX500 Steel Frame Conversion (SFC) => Topic started by: hunter on August 15, 2016, 03:51:56 PM
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New guy here, really enjoying the site and learning a crap ton. My conversion started the second I bought the KTM with a blown motor, was hopeing for a simple topend fix but the head was toast. Off to google for alternatives and that's where I found you guys. I have not made it to far yet but have started ordering parts I know I will need.
What I have so far :
2007 KTM 250sxf
3 -1987 KX500 engines (1 Running supposedly, 2 in parts but could have a second running one with piston and rings)
Service Honda kx500af pipe on the way
Need to order/do:
Decomp valve
Hydro clutch actuator
Misc tid bits
Hold ups:
1. Reaming the rear engine mount hole to 17mm. I live in a small town so its hard to find someone who can do this and I wouldn't mind keeping the case oem. I have a few ideas.
-- Have a bushing made for the swing arm holes 17mm OD and 15 ID, would use a Different pivot bolt (maybe one from a earlier year KTM?)
-- I sent allballs a email asking if they could put together a bearing kit for the swing arm that would have a 15mm hole, effectively doing the same as above
2. Exhaust:
-- From what I can tell it seems the KX500af pipe is the best route to start with, but I also assume its not going to just line up. Anyone else use one of these and if so what mods did you have to do to make it work with the KTM frame?
-- Still researching on what muffler to use, hopeing maybe a KTM 300 2stroke one will work maybe different Cone Diameter?
Anyways, this will be a slow moving project as money is the main factor in the way but working on getting that handled the best I can.
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hi
What your engine/ swingarm clearance both sides?
I Have done 17-15mm bushing {not on ktm} they worked out good they do turn out pretty thin[only 1mm thickness}
On my build 12 mm clearance one side and 2mm other side
One bush ended up a straight sleeve and the other sleeve had 6mm collar and need to be about 3mm longer than swingam bush to slide into the frame /
Changing bearings in swingarm will still leave u with 17mm holes in frame
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hi
What your engine/ swingarm clearance both sides?
- I have not checked this as of yet, trying to get the engine in there first with the rear pivot mount and then will cut the old mounts out and mock everything up where the sprockets are aligned.
I Have done 17-15mm bushing {not on ktm} they worked out good they do turn out pretty thin[only 1mm thickness}
On my build 12 mm clearance one side and 2mm other side
One bush ended up a straight sleeve and the other sleeve had 6mm collar and need to be about 3mm longer than swingam bush to slide into the frame /
I assume the 6mm collar was to get the engine offset for the sprockets? I remember reading that somewhere.
Changing bearings in swingarm will still leave u with 17mm holes in frame
Yeah was thinking about that, though maybe some small short bushing for the frame but I am not likeing the idea.
Sorry its taken a bit to get back with you. Crazy busy at work.
My answers up in blue, I loved the idea of changing the bearing until you reminded me about the frame. So I think I am back to the bushing idea or just buying a reamer and taking the plunge on the cases then its just a done deal. Bushings are pretty easy for me to get made up, just need to tell my buddy what I need.
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A quick drawing to let u know what i done / very important that bushing are right length
U dont want to end up with swingarm or motor not tightening properly
The reason for the collar is so u can remove swing arm without removing motor
(http://i246.photobucket.com/albums/gg119/cr500-af/SAM_2410_zps9ewuyrij.jpg)
17by15mm Bushes or in purple :-D
(http://i246.photobucket.com/albums/gg119/cr500-af/SAM_2412_zpsb2xxn2lb.jpg)
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Dave,
Seriously appreciate the diagram and all the info. I was talking with my gunsmith today and he said he had adjustable reamers that would make short work of reaming out the hole, done by hand. Now that this could be a option I am leaning that way just to make life simple. Hopeing to get that done this Sunday if all goes well.
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Small Update:
Things are finally moving forward, Got the hole reamed out last weekend and got the engine in the bike to get a rough idea how things are going to fit. I lucked out and got this Saturday off and was able to get a welder/fabricator to work with me on it to get the Mounts done, pipe fitted w/mounts along with modifying the left radiator. Pretty much all welding done.
Issues that need to be addressed that are obvious and appear to be a common issue:
Stator cover hits the left frame cradle
Kick starter hits the frame as well
250sxf air boot appears to might be able to work
Where is everyone mounting there coils and such?
Anyways should have some pictures to post up after this weekend of some progress.
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Heres a few pictures of the progress. Also some things to note that I somehow never even noticed that should have smacked me right in the face. Front and bottom mount holes were previously reamed out to 12mm and were filled with gasket maker to make what I assume is a make shift rubber mount. I bought M12 bolts for the mounts but I do plan to find some with a Allen head. Mounts were fabricated up and bolted on to the engine and then everything was tacked including the nuts. Then engine came out and the mounts were finished off. My sprockets were aligned with the engine pushed all the way to the left against the swingarm. A 6mm wide spacer will be needed and I already have that made up and on hand. I did not modify the frame where the stator cover hits, we just shimmed it in that spot for clearance. I know things will be tight around the spark plug area so I ordered some shorty spark plugs and the NGK short plug as well. Kicker will have to be massaged a little bit as well for it to kick freely.
Also picked up another KX500 engine today, was told it was a 86 and the cases are in pretty bad shape. Rear pivot hole was attack by what appears to be a Die Grinder and a inch or so has been removed of the right case mount hole. The hole was also reamed out to god knows how big and most likely not square.
BYE BYE KTM mounts
(http://i64.tinypic.com/29e4nzs.jpg)
(http://i63.tinypic.com/2u966qc.jpg)
All done
(http://i68.tinypic.com/2jfq0.jpg)
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Some more progress, slowly coming together.
Mounted radiators - Left radiator needed the bottom spout spun 180deg upwards
Also on the KTM they have this T inside the frame that is integrated into the cooling system. I did not need the bottom part of this T, so we took it apart. I used a m20x1.5 oil drain plug from the hardware store to plug the hole in the bottom of the T. We had to cut off head and make a slot for a flathead screwdriver to fit to screw in our makeshift recessed plug. Reinstalled the Top part of the T in the frame and it will now act as the cross over From Left to Right.
All the Exhaust mounts are done, just need to get a small piece bent up to mate the silencer to the headpipe.
Mounted up the CDI and Coil, just reused the factory KTM locations.
For a Intake boot I used a 2008 KTM 250 SX 2 stroke boot, DO NOT put the boot in first. You have to mount the carb to engine then put the boot in and mount to the carb before trying to install the boot. Doing this, allows the boot to take on a new shape after installed and fits like a glove....you will cuss a bit trying to get it installed lol.
(http://i67.tinypic.com/2hqfrph.jpg)
(http://i63.tinypic.com/2echn28.jpg)
(http://i66.tinypic.com/rsd5dy.jpg)
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Looking good man, she is coming along nicely!!!
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Great looking bike, you've made some great progress so far. How close are you to riding it?
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For a Intake boot I used a 2008 KTM 250 SX 2 stroke boot, DO NOT put the boot in first. You have to mount the carb to engine then put the boot in and mount to the carb before trying to install the boot. Doing this, allows the boot to take on a new shape after installed and fits like a glove....you will cuss a bit trying to get it installed lol.
hmmm, that sounds fun. :|
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Thanks guys! The bike is starting to come together, my main hold up were the welding and the rear pivot hole. My work schedule has been 6days a week so time has been a issue. In perspective this is going really fast, I bought the KTM Roller in the last weekend of July and basically in a month went all out buying up engines etc trying to make this happen.
So far the things I have left to do before I can actually Ride it, and assuming no other issues pop up:
Rebuild Water pump, and replace bearings and such in the clutch cover ( I have a upgraded water pump coming)
Go through the Carb, make sure its up to par and do initial jetting.
I ordered new controls and cables - G2 2Stroke perch, Moose ez3 Clutch perch and cables for those
I got rained out today, so if I can find someone that can do the exhaust today I am ahead! The parts I have ordered should be here at the beginning of next week. Will probably get the engine work stuff done this coming up weekend.
So if things go the way I hope, Ill be trying to kick it over in 2 weeks.
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For a Intake boot I used a 2008 KTM 250 SX 2 stroke boot, DO NOT put the boot in first. You have to mount the carb to engine then put the boot in and mount to the carb before trying to install the boot. Doing this, allows the boot to take on a new shape after installed and fits like a glove....you will cuss a bit trying to get it installed lol.
hmmm, that sounds fun. :|
Its really not to bad, and when you look at it all your thinking man that's close but no cigar. My buddy suggested doing it the way above, and after its all in it look awesome. I did use a new boot though, so the rubber was really soft I can imagine with a used one it would be a &*%$&*$$*$(($@@!!!! lol.
I will try and get some pictures of it today if I can and when I strip the bike down to get the frame powdercoated I will take some pictures of all the little stuff we did to make it all work like the T in the frame.
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yeah...I was being sarcastic....I enjoy a challenge just as much a the next guy.
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Fox - I hear ya, the airboot was pretty easy, it just doesn't look like it would work. Just trying to help out the next guy that might try one of these, as it seems its the small things that are the things that seem to be the issues that need figuring out.
This is my first conversion, so I am learning a lot....
Oh and I also picked this up this last Friday, 2008 250xcf with blown bottom end, Already had a street legal title so I promptly went and got plates for it. Thinking this one will be the Supermoto one! :mrgreen:
(http://i63.tinypic.com/vzbsoz.jpg)
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You're building quite the stable of cool KTM/K5 conversions. We'll need pics of this build also. :-D
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Fox - Just trying to help out the next guy that might try one of these, as it seems its the small things that are the things that seem to be the issues that need figuring out.
I know....and a fine job you did. :mrgreen:
all good.
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Update-
Not much has happened lately, using my buddies garage for the project so the last few weeks hes needed it. Exhaust is done and mounted but really not happy with it. Sticks up above the rear fender, needs some pipe cut down and a mount made. With that said, its not a high priority and can be done when ever.
For those that might be trying to run the G2 2stroke perch and PWK39 (or other PWKs ?) I ended up using a Motion pro T3 #10-3000. Threads into the carb cap and the perch and solves the WOT if the cable gets pulled. This cable is for KTM 2strokes and is 5inches longer then there stock cable, and is about factory length for the two Kx500 cables I have here.
Just need a day to put it all back together, mount the two perches and prey like hell it starts up lol. Getting excited, should have been done by now. Hopefully get to ride it a bit then I will tear it all down for powder coating this winter and take care of any details that need to be addressed.
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Update:
Bike runs, no leaks, started 3rd kick and idled somewhat lol.
Still lots of small things to do along with getting jetting correct. I did ride it around a bit and it seemed pretty boggy in the bottom end but seemed to clear up some in the higher rpms. Also seemed to power out pretty fast. Most certainly not a wheelie monster yet lol
I was ear to ear smiles when she started and idled.
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Update:
My buddy and I worked on my jetting today, started off at 168/58 needle in 3 clip, 1.5 out on the air screw which was my base jetting. I was running extremely Rich. We started leaning things out and at this time we are at 158/42 , needle clip in the second from the top 1.5 out on the air screw.
Mid has cleaned up tremendously, still a little bit fat down low. Going to hopefully try a 40 tomorrow and see if that helps.
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Build is looking great! I am creating the same monstrosity- 2007 450 SXf with 1985 KX500.
I have made an adapter plate to convert the carb boot to the later 6 bolt later type. I've also got the later Kehin carb also(1994). I used a 2007 300 exc air box boot to connect box to carby which fits perfect.
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LONG OVERDUE UPDATE! -
SO a lot of things went sideways on me on this build.
1. Lost compression out doing final jetting. Don't know if I ran it to lean or what. Was able to limp the bike home. Looking back, was probably low compression to begin with as it wasn't to hard to kick over.
2. Had my jug bored out for a 87mm Wosner piston. Went to install and ring gap was all wrong and to wide. Come to find out the guy that bored it went to far so I had to much slop. Had to take it somewhere else a yr later to bore it once more to 87.5. New Wosner piston of course.
3. When I had the motor out I said aww screw it Ill have the frame and some misc parts Powdercoated Kawi Green. Powdercoat Shop screwed the pooch and I lost my VIN. 7months of back and forth with WSP and a drive finaly across the state and I was able to recover my VIN....it now looks like a drunk 3yr old punched the numbers into my frame. WSP....if your read this figure out a new system.
Where I am now! -
1. Motor is put back together minus the head which is currently with our very own Larry getting his work done.
2. Just picked up a older PWK 38 airstriker to replace the pwk39
3. Figure out a better airfilter system - looking at going pod with cover or possibly a newer airstriker that is shorter to allow the ktm boot to fit better.
4. Fix my muffler mounting, guy that welded up my stinger went all free lance on me. Need to cut the welds and redo it so I dont have to cut the rear fender to fit.
5. Buy supermoto tires to put on my Behr Supermoto wheels
6. Wire up the bike for the street and get in inspected and get a plate.
7. Terrrorize the back roads!!!!
On a side note, Ive been searching some starting points with this carb for the 5-hundy. Theres nothing wild about my motor 1.5mm over with some porting in the jug. The airstriker currently has a #6 slide, and r1172n needle. There are some scratches on the front of the slide, nothing you can feel. I have read about useing the Yamaha needle and thats about it. Also heard the STIC metering block is the tits...just dont have the coin for that right now.
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jetting i would be starting AROUND 1368n needle 52piloT 170main
Check the metreing block oing before you start {youtube it}
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jetting i would be starting AROUND 1368n needle 52piloT 170main
Check the metreing block oing before you start {youtube it}
Mine was bad on my carb before I changed over to a Lectron. Changing that o-ring made a big difference.
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jetting i would be starting AROUND 1368n needle 52piloT 170main
Check the metreing block oing before you start {youtube it}
Mine was bad on my carb before I changed over to a Lectron. Changing that o-ring made a big difference.
Most metering block oring seals are leaking on secondhand pwk / 3 or four differant points where the leak
https://www.ebay.com/itm/Jet-block-o-ring-1-Keihin-PWK-33-41-carburetor-35-36-38-39-40-mid-body-gasket-/201306545569
the price of them seems to gone up over the past months :-)
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What kind of gasket carb sealer does everbody use to hold oring in position for fitting?
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Will definitely look into the metering block oring. Thanks for the heads up on that one.
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jetting i would be starting AROUND 1368n needle 52piloT 170main
Check the metreing block oing before you start {youtube it}
Keep the #6 slide as well?
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jetting i would be starting AROUND 1368n needle 52piloT 170main
Check the metreing block oing before you start {youtube it}
Keep the #6 slide as well?
never noticed much differance with slides / 6 or 7 fine
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Update:
1. Head came back from Larry. Its so d**n nice I almost didn't install it. It also makes everything else look like crap lol. Thanks Larry!
2. Good call on the Meteringblock oring. I barely touched it and it broke apart. New o-ring and 1368n needle clip on center with 168/52 installed. Couldn't find a 170 local to me.
3. Got the Top end done, motor is in bike. Need to order some new rubber mounts for the radiators.
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New update:
Pretty much got the bike at about 95% done last year. But was late fall. Decided not to start her up and winterized it.
Brought her out this week to finish her up and double check things. She kicked off first kick! Done a few heat cycles. Down side is after sitting the brake components are shot so I'll be rebuilding everything. Parts should be here next week for that. Then it's time to work on the jetting...but I think it's pretty close.
Will add some pictures as I start cleaning her up. Thanks to everyone who has helped me along the way on this project.
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Heres a current picture. Still trying to get the front brake bled...bastard! Hopefully be working on jetting today.
(https://i.postimg.cc/fWj0rFr0/20200429-135425.jpg) (https://postimages.org/)
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Looking good! 8-)
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Minor hiccup today, noticed some oil coming through my powervalve seals by the linkage. So I'm going to address this before continuing on with jetting. I'm a little bummed but it needs to be addressed.