I just purchased a barely used YZ450 yesterday to use as a track only bike, it's in excellent condition other than needing tires and some TLC. I have a 2003 WR450 that I picked up a few years ago in similar condition and fixed up for dual-sport and trail riding, of course this lead to getting the itch to ride motocross again (can you say mid-life crisis?)
I've been lurking on here to see whats needed to make the YZ track ready and to be honest it looks like very little to make an old slow guy plenty happy but I can never leave well enough alone, ever... So here is my to-do list before the spring.
PLEASE chime in with any must do items I don't have
1: Oil change and add magnetic drain plug. No real idea when the last oil change was but it looked clean on the dipstick. God know what kind of oil it is, the person I purchased it from bought it from the original owner and only rode it twice, not ideal I know but I rolled the dice that it's OK, fingers crossed.
2: Suspension service, shock is leaking and full of air but I'd do this regardless, People seem pretty happy with stock springs and valving so only a service, for now, woot... Keeps cost down.. FYI, I'm a 175 lbs slow person
3: Add o-ring chain, is a 50 tooth sprocket absolutely a necessity? The stock sprockets have zero wear on them but I'd like a 49 on the WR so I'm temped to do a swap if you all think it's money well spent... FYI I've always been a mid pack B motocrosser and have no reason to suspect I'll be any better now
4: Clean carburetor and add a HD acc pump spring and an adjustable fuel screw plus replace any bad rubber parts; ala what I did on the WR a couple years ago. Add twin-air filter.
Everyone seems happy with stock jetting so that makes life simpler and cheaper! I'll pull the muffler apart and repack (I have no idea what FMF uses for their packing from the factory?)
5: Tear down and pack all the bearings with grease and lock-tite or anti-seize the bolts and check everything with a torque wrench
6: Make it blue, its white.
Put the OE stuff in a box and throw on a set of blue plastic and a gripper seat cover, some tasteful graphics and of course some nice pre-printed numbers!! Back in my day we had to put on our own backgrounds and numbers, things have changed for the better since I've been in retirement!
7: New tires, I think this poor bike did only asphalt miles (They look worse than my WR's with dual-sport miles, it may have never been off-road). I'll remedy that!! Thinking Pirelli MXMS for Indiana springtime?