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All new to me 08 450xcf

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I have been out of the KTM game for years and just picked up this 450xcf for a smoking price. Mechanically it is sound bit general maintenance has kind of been neglected. The bike Sat for 2 years. Gonna do a tear down and re familiarize myself with this KTM, glad to be Back, my last 5 Kim's were 03 to 05"s.


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I had this very bike a few years ago.    I LOVED it...    This is one bad ass machine.    I think the forks need work, but that motor... damn!  Its an exciting bike to ride.   I rode mine in the desert.   It handles great, although the forks weren't as plush as the open chamber forks.   (another story)

My problem was that I did not know how to keep it running.   That RF4 motor has some unique things about it.   This was KTM's first year with that motor and this exactly one is what earned KTM its reputation about first year teething problems.  You should read up on it.   You'll find volumes of information on this engine.   Talk to the experts.    Call Chris Blais or somebody like that who can tell you EXACTLY what you need to do.    Definitely upgrade the oil pump rotors if they haven't been.  Don't wait, do it now.

Other than that, enjoy your bike...    (sorry if I sound negative...  but I really liked that bike and wish someone had told me what I'm telling you now.)




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Nice bike.  Sounds like a good deal to me.   I had a 09.  First thing I did was piston and rings.  Mine had a 100 hrs and still ran good.  Ring gap was huge upon tear down.  I also shimmed pressure relieve spring.  Here is a copy of a bulletin.

Subject: KTM RF4 Engine Maintenance Guidelines
Affected Models: 2007 - 2009 450 / 505 SX-F and 450 / 505 XC-F,
2009 450 / 505 SX ATV

Initial Information:
» The following information in addition to the Periodic Maintenance Schedule for the above
mentioned models, will ensure that the RF4 engine is maintained in the best possible
manner. Always refer to the owner’s manual or shop manual for correct procedures and

This bulletin is not a warranty item.

Oil Pressure Pump:
» During the course of the first service interval at 3 hours of operation, it is recommended to
check/adjust the axial clearance of the oil pump (pressure side) to maintain optimal oil
» Measure the width of the pump rotors, measure the depth of the pump cover, then subtract
the rotor width from cover depth. The result should be a clearance between 0.01 –
0.03mm. If the clearance is greater than 0.03mm, lightly surface the cover with 1200 grit
sand paper on a flat surface until the proper clearance is achieved.

» It is also recommended to add a 1mm preload washer “p.n.0988060121” to the oil pressure
bypass spring (8mm AH plug screw side) to increase oil pressure during spring inspection.

Quote from KTM Talk on this subject:

Another issue besides pump/cover clearance is the spring in that cover. Remove the spring an check the overall length. The motors we've seen with issues have had a spring length in the 36-37mm range. I just checked my bike and it measured 38.75mm

One of the first indications of potential issues is an inconsistent rattle in the motor, cam chain tension due to low oil pressure.

On top of this info, Dustin tested the relief spring in his digital load cell and from cold to hot (as in a hot running engine), the spring lost about 1/3 of it's stiffness !!!!!!!! so saggy spring plus hot engine = major oil bypass on the pressure side = screwed low end.............

Edited by Firedude

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