I've been saying I want to start riding some MX for the past year or so and since I got a couple months off work because of my broken leg I figured it was as a good of a time as any to start looking around for a little project. might not be able to ride but wrenching keeps me from going completely crazy with boredom...
I started looking around at used bikes. the first plan was to get a 125 2-stroke because I figured if the engine went boom it wouldn't cost me a whole lot to repair. I started having doubts as I'm a pretty convinced 4 stroke guy, plus the fact my mates who had quite a bit of mx experience were telling me to ditch the 2 stroke idea wasn't helping either. some future supermoto plans for the bike made me go 4 stroke in the end. a 450 I knew was going to be too much for a guy with little MX experience, I already rode a friend's YZF450 around a pretty gnarly track and I was just about dangling on the end of the bars. so I was looking to go lite, ie 250.
I didn't want to spend a whole lot on the bike itself because I knew I was going to take it apart completely and overhaul it, so it didn't matter if there were some bits on pieces that needed work. I went with a 2010 250 SX-F. it doesn't have a link at the back like my 450 but I honoustly didn't want an EFI bike because KTM were having some issues with it the first year they made the switch, and since the 2011 250 was the first EFI 250 my only options were a 2010 or older model. carb'd and older style bodywork, had some 530 flashbacks already.
the bike itself was in a fair condition but you could see it had been taken apart once already and they basicly put it back together with just about any (rusty) bolt or nut they could get their hands on. nothing seemed to match and I'm that anal (yes I said anal) that it was bothering me a bit to see how the bike was reassembled. the bike had been run on sand tracks close to the sea, failure to hose the bike down ment a lot of stuff had started rusting and showed signs of salt eating it's way into metal parts. not stuff you want to see on a bike that's only 2 years old but again it wasn't a big deal since it was gonne be taken apart and cleaned up completely.
so enough with the boring text stuff, on to pictures. little sidenote, tips I highlighted in bold.
how it looked when I brought it in:
the easy part, removing plastics:
the suspension needed to be resprung, the guy I bought it from was about 220 pounds. I'm 140... little difference. luckily he kept the stock springs which work for my weight. out with the forks and shock. the front end also needed new head stem bearing. the triple clamps were tightened down so much I literaly had to knock the top nut loose, it simply wouldn't budge with just wrench. I was surprised I was still able to turn the bars considering how tightened down everything was.
biggest pain in the ass is I have no room for a work bench in the garage, I need to park my dad's car outside to actually have room to work in.
subframe off, again those bolts were tightened extremely tight. how I didn't find any stripped threads on this bike is beyond me... radiators off as well, flushed them out since they had some gunk in them.
engine out, bare frame left.
for those of you that want an easy way to remove the alu coolant tube from the frame, don't bother with the KTM tool most say you have to use. get a 12 mm hex socket for your wrench, insert that in the pipe and it will grip without doing damage. the top rubber piece will come out with a little wigling. when reinstalling the T-pipe you do need to use a sealant like loctite 577 to keep everything water tight
first cosmetic fix. the seat had a tear in it and the foam had some moisture damage. I sanded the foam down in certain area to clean it up and added an extra piece to make a step seat out of it. I also spray painted the foam to keep more moisture from seaping into it. the spray paint penetrates the outer layer of the foam making it more or less water repellent.
new blackbird cover for the seat. when you mount a new seat cover staple down the front and the back first to keep the cover in place. then start at the front and work your way back going from side to side keeping the cover tight every inch you move further back. once you get close to the back remove the staples you applied there in the beginning and reapply them so the that cover fits nice and snug. I found this to be the most effective way to keep the cover nice and tight around the seat. stapling it down in different areas then filling up the gaps will more likely leave you with a wrinkly cover.
started work on the motor but took it to a friend's shop to make life a little easier, now I actually had a bench to work on. the initial idea was to take it apart completely because I don't trust used bikes in general. by complete coincidence it turned out my suspension guy had gone through the motor at the beginning of the year since he knew the previous owner. he assured me the crank was good and a new piston plus camchain was installed. so I binned the teardown plans and just went over the obvious things. checked the valve clearances, all were within spec. checked the clutch, tiny amount of grooving on the clutch basket but nothing serious that would require work or a replacement part. springs and plates were all within spec. checked the stator and flywheel, found some dirt building up in there, mostly dust that found it's way inside through a stator cover weep hole at the bottom. drained all the oil I could, changed the oil filter and cleaned all the screens. ditched the stock hydraulic camchain tensioner and replaced it with a dirt tricks automatic one. the stock tensioners are known to fail and on a motor that spins around 12,000 rpm it's not something I want to risk. I've run dirt tricks tensioners in my last 3 bikes and they never miss a beat. they take 5 minutes to install and are fit and forget.
the stator cover showed some wear and tear. rather then buying a new one I choose to sand this one down and respray it. started with 80 grit waterproof to remove the old coating. then went to 200 grit to smooth the bare metal out.
primer, applied in several coats.
color, also applied in several coats
that's how far I am. got the frame and swingarm back from powdercoat today so reassembly will start saturday. I'm heading out to the UK on friday.