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KXF300exc Uber Dirty

21K views 82 replies 15 participants last post by  Shmitterton 
#1 ·
Not a Fighter, I know, but I've been waiting awhile to do this and I figure some of you will find it entertaining.



I've been talking about doing this for awhile, and I've had alot of people laugh, tell me it's pointless, tell me I'll never start it, or never complete it, etc. Well, here you go haters, I'm doing it.


Uber Dirty: 1996 KTM300exc engine going into a 2004 KXF250 chassis.


I started tonight for the first time. Got a decent start, looks promising:

Here's the messy garage:


Here's the donor bike. I rode it a week ago, took me about a half hour to get the engine out, here's how it looks:



Better look at the donor frame/engine mounts:




Front cradle:
 
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#4 ·
Hopefully it will be fun to ride, I'm pretty sure it will be.

It will be fun to build, and that's half the fun for me.
 
#3 ·
Here's the engine, looks filthy right here, but it's actually extremely low time, prob under 20 hours since brand new, and about 10-15 hours on a brand new top end with new plating. Def needs a good cleaning. I'm also gonna replace the countershaft seal and shift shaft seal. They are notorious on these KTM for several years.





Box o parts, I need to get a dent out of the pipe, and the shock needs service. I'm not sure which shock I should use. I'm not even sure if I have a choice. I'll prob have to use the OE kawi shock.




Here's the lucky recipient, 2004 kxf250, same bike as RMZ250 2004-2006





 
#6 ·
KTM swinger pivot:




KXF swinger pivot:





Caliper shows width of KXF engine:










PO screwed up the clicker, hopefully that's not a sign of a big internal problem. I plan on rebuilding them anyway, so if possible, I'll replace that part. These forks are the late model KYB bladder forks. I've heard the bladder system is not great, but they are supposedly really good when converted to open bath. I'll prob seek some advice revalving them and do that myself. From what I understand, basic changes aren't too complicated. More on that later.




Caliper shows the corresponding distance in the kxf chassis from the swinger edge to center of chain.
 
#9 ·
i agree shmitty. this is goin to be an awesome build. streetable i hope
 
#10 ·
Dirt first, hopefully street later!!!!!
 
#11 ·
Anyone know where I can get that clicker?

It isn't real clear to me on the microfiche.

 
#12 ·
92009 looks like the bleeder screw to me.
 
#14 ·
The parts list refers to that as a nut, I'm kinda stumped here. I don't have room in my garage to take the fork apart yet, i need to throw the xr4 engine back in first and finish working on dad's 250mxc
 
#16 ·
I stripped the kxf down to the bare frame and I'm working on matching the engine to the swinger.


It's a challenge to say the least. I'll post more pics soon, but i'll need to bore out the engine mount to fit the kxf swinger pivot. An 11/16" drill bit is .6875", do you think that's too much clearance? McMaster-Carr sells badass carbide tipped straight fluted bits that would make a reamer quality hole, but I'm not sure if it's worth $68 to drill one hole, lol.

That's only half the challenge though. I need to get some clearance horizontally also, and i def can't take it all off the engine cases. I may take some, and for that I'm looking at tools like these:

http://cgi.ebay.com/1-STRAIGHT-SHAN...075?pt=LH_DefaultDomain_0&hash=item3cb5a4b8d3

but I def need to get some space out of the swinger, so i need to either find a narrower seal, or shift the bearing in the swinger, which would require a custom bushing and cutting of another bushing and another special countersink. I'll need to post pics to clarify.



So how much clearance do you think for swinger pivot? any helpful thoughts elsewhere?
 
#17 ·
Stripped her naked:





Real fun starts:





Mock up with KTM pivot:




Tank clears fine:

 
#18 ·
closer look at downtube cutaway.




Not so lucky here:



Looks good closed:



Pic shows interference:










 
#19 ·
Been struggling with the engine/swinger mating.

I think I finally made a decision, I got a 21/32" drill bit and new stock sized bearings and seals for the swingarm. I still need to remove some material from the right side. I think I'll try to take up a little off the bushing, a little off the thrust bearing washers, and the rest off the engine case. I still need a way to take metal off the side of the case. I need a facing tool of some kind. Or a giant counterbore.


real updates coming soon.
 
#20 ·
Yesterday I ordered the correct 17mm drill bit, and a 1" countersink tool with a 5/8 pilot to use as a spot facing tool to remove metal from the case sides.


Tools should be here monday or tuesday.


Ordered a swingarm bearing kit from ebay and the kit is missing more than half the stuff. I contacted the seller but I'm not sure yet what he's gonna do to fix it. Hopefully that works out all right. At the moment I'm pissed. If he fixes it, I'm ok.
 
#23 ·
I totally understand, I have run into ALOT of naysayers though, lol.

There are several reasons, first being, I can, second, WAY cool woods bike.

I got the 96 ktm300 for $270 on CL. Seized engine. I found a piece of the radiator hose stock sideways in the rad hose blocking the thermostat, so the radiators never flowed at all. There wasn't even any fluid besides some seeping past the blockage downstream from the thermostat. Long story short, the bike had prob less than 10 hours on it. So after new piston and elecroplating, I have an essentially brand new engine. The chassis is 15 years old, and isn't anything to get excited about. It's a little heavy, claimed dry weight 230lbs. It's also bulky, I don't like the ergos at all. But I'm totally in love with the engine. Luggable and totally berzerk all in one package.

The kx250f is an 04, and I got it for around $400 or $450, I can't remember, but it's the newest mx bike I could find with a steel frame. I chose steel because there's a little more room in the frame, and I like the feel of a steel frame with a bit of flex. I'm just as confident, if not more confident welding aluminum, but there's more need to alum to be heat treated after a mod like this, so everything for me, pointed right to steel. It's a 250f, so it's got a little tighter wheelbase, MUCH better ergonomics, WAY better suspension, linked rear end, and a claimed dry weight of 195lbs. I suspect my 2t engine might weigh less than that 4t that was in it, so I should have an extremely light bike with an awesome engine. I plan on pulling shims myself or getting race tech kits for both front and rear, and lacing an 18" rim on the rear. Plus since I have both bikes, I have alot of part I can cannibalize, brembo masters, 18" hoop, etc....


I just think it will be a cool platform, and it will cost alot less than a new enough ktm300 to make me happy.
 
#25 ·
haha, why? you wanted them?


You still interested in frontend parts?

You said you had some XR4 stuff, do you have a shock by chance?
 
#26 ·
I don't have a XR shock, but I got a CR shock that I believe is a Fox. I haven't confirmed it yet though. I'm kidding about the brakes. I need to worry more about the 250 engine before anything else. I haven't decided the fate of the XR4 yet.

I told you about the goofy shit it started doing right? I need to figure out how to square it away and then maybe we can talk about the edelbrock.
 
#27 ·
We'll figure something out, if the edlebrock works out for a trade it may be helpful, but if you decide to keep it that's totally cool.

You made any progress on that 250?


I'll prob end up selling a complete 96 300 exc frontend. It's old but more desireable frontend than the first WP fork generation. And fresh bushings/seals/oil.
 
#28 ·
OK, frustrating setback.

I clamped the engine down the other night to drill out the case. Drilling went fine from both sides, no eccentricity, or wandering or anything, holes look awesome, but the damn dowel in the center keeps spinning instead of letting me drill it. I wouldn't have thought this would be a problem, because if need be, I should be able to drill both sides out, and then just pushing the dowel out one side. Go figure, the damn dowel has a 15mm ID and a 19mm OD. I would never in a million years guessed the dowel to be that thick. Most locating dowels are very thin.


All this means is I have to split the cases to get it out. I started putting my bros XR4 together to get it off my engine bench, and I ordered the gasket kit yesterday. I already have the seal kit.


I think I'll split the cases today and see what the hell's going on in there. Also I aquired my tool to remove metal from the side of the cases, it works AWESOME. I'll post a pic later today.
 
#29 ·
Got some small updates.

Here's the new tools I got. The light colored bit in the plastic sleeve is the 21/32" bit that was too small. The black one is the 17mm bit. The one in the middle is the changeable pilot counterbore. The sizes on it are not ideal, but it still works awesome. It's a 1" counterbore with a 5/8" pilot.





Here's a test demo in 1/2" alum.




It's amazing what you can do with basic tools to make up for not having machine tools.
 
#30 · (Edited)
This is my best attempt to get a shot of the dowel in the cases. Discovering this wasn't coming out was FRUSTRATING to say the least. Gaskets and seals to rebuild this was about $85.



This is the first time I've been into this engine, if some of you recall the back story. I've been really pleased with what I'm seeing so far. The engine itself is basically brand new. I havn't located any play in bearings yet, the gears and shafts are perfect, you can't even tell where the plates push on the basket and hub, etc...it's near perfect.




I bought a kx250 airbox off ebay. The subframes are similar designs and the carbs should be in similar positions. A test fit shows it could be doable, but more likely I'll try to get the kx250 boot on the 250f airbox. Too early to tell, more on this later.

 
#31 ·
Success!

Finished the engine rebuild and the kxf swingarm pivot now fits through the ktm engine!!!!!!!!!!!!!!!!!!:banana:

The engine dowel was thick enough that I was able to clamp it down and drill it out to 17mm.

Swingarm and linkage bearing kits are on the way, ordered the All Balls kits from RockyMountainATV. They are always fast, reliable, and at a fair price. I'm STILL working on getting my money back from the stupid ebay seller sledpartsguy, more than 20 days after he received the incomplete kit I sent back. Avoid dealing with them if you can. Horrible communication and service.
 
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