Posts
1067
Joined
1/4/2015
Location
Austin, TX
US
Edited Date/Time
1/10/2022 5:49pm
Last week I picked up a 2008 KTM 450 XC-F that the owner proclaimed would run, but had a bad habit of smoking when it ran. He said that the previous person agreed to but it, road it down the rode and it came back smoking oil, so he bailed and it sat for 2.5 years. I scored this for $900. The plan is to get it street legal here in TX and keep a spare set of wheels so it can still be ridden as a buddy bike.
Here is what it looked like when i picked it up:
Here's how it looked mid way through the tear down:
The throttle cables were held together with a zip tie and hope:
This thing was covered in oil; the counter shaft seal failed, the valve cover seal failed, and somewhere along the lines I think that crush washer failed due to the impression it had.
I've got the valve cover off and found a bit of a mechanical milkshake in here:
To continue my progress, I need to go to the hardware store and fin a bolt that matches the thread in the crankshaft that locks it in TDC. KTM used to sell the tool that did that (P/N 77329010000) but it looks like it's been discontinued, so a trip to ACE is in order, but I think I might need to grind down the edges to get it to thread properly.
Here is what it looked like when i picked it up:
Here's how it looked mid way through the tear down:
The throttle cables were held together with a zip tie and hope:
This thing was covered in oil; the counter shaft seal failed, the valve cover seal failed, and somewhere along the lines I think that crush washer failed due to the impression it had.
I've got the valve cover off and found a bit of a mechanical milkshake in here:
To continue my progress, I need to go to the hardware store and fin a bolt that matches the thread in the crankshaft that locks it in TDC. KTM used to sell the tool that did that (P/N 77329010000) but it looks like it's been discontinued, so a trip to ACE is in order, but I think I might need to grind down the edges to get it to thread properly.
Sea Class, how you liking Texas? And sweet score on the KTM.
For DS I recommend doing a radiator fan and get the biggest LIPO battery you can stuff in the battery/airbox. trailtech also makes a higher capacity stator since the stock is I think 30 or 50 watts.
Besides the leaks the most likely culprit for oil consumption is a set of rings beyond spec. The bores of the cylinder are so hard they wear the rings out in about 60-80hrs depending on how hard they were run. Good news is typically you can get away with just a ring swap. If you really need to do a piston and rings have someone measure the cylinder as Woosner sells a bunch of size pistons for it to get fit right.
Nice score...
I absolutely miss some aspects of CA, but nowhere is perfect!
The Shop
I also find it odd that the only way I can get a quality piston from Vertex is to put the SX-F version into their model finder. Would you have a strong preference of cast vs forged in this instance? I’m leaning cast right now
I had to check my notes but back in 2012 I had Dave Hopkins in WA go through my head and hone the cylinder for a slightly larger Wossners piston at roughly 120 hrs. I don't see a part number on the invoice from Dave and I'm not sure if Dave is still doing this work but you can check over on KTMtalk to see if he is still around.
I built my bike to race NETRA here in the north east for the A open class so I spared no expense. Here is what I remember. lol
Carb - started with JD jetting kit and Oring Mod but ultimately ended with the R&D Powerbowl 2.
Motor - Power parts High flow water pump, reklus clutch, Trailtech flywheel and stator, dirt tricks cam chain tensioner, and shimmed oil pump mod. FMF SS powerbomb exhaust mated to a FMF Q4 exhaust
Chassis - normal rock guards for the north east; skid plate, rear brake fin, bullet proof chain guide guard, fluidine radiators with BPD machined guards and hi pressure cap, EE tall seat, IMS pegs, and Cyra hand guards. Maier made a wider bolt on rear mudflap that is really good to keep the goo off too and has enough surface for a license plate mount.
Suspension - Sprung for my weight and valved for our terrain with some settings I developed over many years of racing here in the north east. I did put racetech gold valves in the forks which really made them more responsive than I could ever get out of the stock fork valves even when modded.
I still have a decent stash of parts for it if you get into a bind. Clutch/water pump cases, stator cover, radiators, stock exhaust and various other parts (KTM rod kit too).
Since I "retired" in 2013 and then started vintage racing I've been slowly going through it to DS around town myself with the occasional turkey run if I can find the time. The plan is the Tusk fan and lighting kit and some DOT tires. Swap out the brake pads for some carbon ones and may be decrease the sprocket size in the back a tooth or two. I'm contemplating a key setup or hidden switch for the ignition but it all depends how much I ride it.
He is a picture from this summer just after I went through the bottom end with new oil pumps, main bearings/seals as I had to swap out the cases due to two of the head/cylinder bolts pulling out threads when riding with no coolant in an enduro back in 2014.
Vertex do make quality pistons if you can't find a Woosner.
Yanked the drain screen filter out and didn't exactly find the best of news; I confirmed that the head gasket has been smoked as I found bits and pieces of it in the filter, but I sadly also found some metal bits. i'm hoping that it's just engine degradation over time as the oil was thicker than syrup and didn't contain any coolant.
When my new set of feelers comes I will measure valve lash and then tear the top end down to give you guys a better look
I also strongly suggest you replace the 3 oil pumps in the motor. They are plastic (get hard and brittle with heat/time) and for under a 100 bucks will give you piece of mind, there was also a shimming trick on the pump under the shift shaft to increase the pressure some as the early years had weaker bypass springs. The dirt tricks manual cam chain tensioner is another must do for 2 reasons. The oem uses oil pressure to keep cam chain tension so at lower RPMs you get less pressure on the chain tensioner. You also block off that oil port which puts more oil to the head for the valves and cams for a double win. It's less than $200 for both those mods but well worth it to keep the motor going for many years to come. I did them right away on mine and the internals looked awesome at 150hrs racing the bike off road in the expert class and the valves stayed in spec since day 1.
When I was looking at buying a blown 2008 450XCW, I think remember reading about a mod where they changed the oiling system to link up the two case halves ... don't remember exactly but I recall that some of these motors had lubrication issues.
Definitely worth jetting all your oil passages, while you can.
A trick I learned from my current-gen KTM was to always check oil pressure at the cam jets by e-start, before you close the valve cover.
When I used to work on 5-valve Yamahas, they would always recommend checking the oil pressure at one of the external oil line banjo bolts, but I don't see too many references to that in KTM manuals except for an external pressure gauge you're supposed to connect to the cam chain tensioner. Always seemed like there must be a better way. Best of luck with the build and fully-assessing the bottom-end.
Pit Row
These motors were fairly good for power and durability, they often won the overall power tests in the mags from when it was first introduced in 07. If you do find that you do a lot more road riding than dirt you may (long term) invest in a cush hub for the rear wheel setup as pavement can be murder on transmissions and clutches.
Ever so slight side to side play in the con rod, but no radial play whatsoever. Feels tight enough to me; don't think I will be splitting these cases.
There's definitely wear, but absolutely smooth as a baby's bottom. I'm going to hit it lightly with some WD-40 and a green scotch brite in a criss cross pattern right before assembly.
The carb on the other hand, was disgusting. Somebody must have ran without an air filter or something to that accord, as the mud/grime at the bottom of the float bowl was disgusting.
It appeared to be running a:
185 main
85 Cold Jet
OBDTR needle (5th position from the top, stock is 4th)
The idle air jet broke off in there and I need to go get it out.
Yamalube make a nice carb dip that is really good at removing ethanol varnish. Not sure if Motorex/KTM has something similar ...
In the service manual, they referred to it as as the 'force pump' and that's why I could never figure out the circuit, so this is making a lot of sense.
It looks like i don't even have to split the cases to do it so I think these 3 are my next rocky order.
Well, did not expect this project to take nearly a year but hey, here we are. Home ownership and life can get in the way like that.
Some updates; clutch cover and water pump cover primed and painted. I will take an orange paint pen to the RF4 and KTM logos; neat little thing I've done in the past. Doesn't last long but it looks great.
However, when I went to prep the clutch case for paint; I found what I thought was a terribly done JB Weld underneath the water pump, so I started cleaning out years of oil and dirt from underneath.
This lead to me finding a hole, that very obviously looks like it came from the factory. Can anybody explain what this is? It is EXACTLY the width of a 3/32 drill bit and I can not find any information in the service manual nor the OEM Microfiche at RockyMountain.
It's a hole that leads to the back side of the water pump seal. If the seal fails you'll have water or oil dripping out of it. They borrowed this trick from the automotive industry.
Since I raced one of these for a few years and still have mine, I have quite the pile of parts if you find your self in a jam. Normal stuff like covers, stator, radiators, connecting rod kit, etc.
Man, I might have to PM you. I have so many questions about this bike and I'll definitely probably need a part or two lol
This will last about 5 minutes off road but what the hell, it looks cool. Will need a second coat but I’m digging how it looks.
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