2007 Yamaha YZ250F

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Repair dent in exhaust

Check out this sweet end of season deal!

Now with the new stock seat.

YZ250F with new seat
2007 Yamaha YZ250F


YZ250Fw parts list and exploded diagrams
Valve clearances:
Exhaust 0.17 – 0.22mm (0.0067 – 0.0087″)
Dec2017: L 0.203mm, R 0.178mm
Jun2018: L 0.203mm, R 0.178+mm
Dec2018: L 0.178mm, R 0.178mm
Shims: L 1.72mm, R 1.75mm
New Shims: L 1.70mm, R 1.73mm
Jan2019: L 0.203mm, R 0.178+mm
Jan2020: L >0.178mm, R >0.178mm
Mar2021: L >0.203mm, R 0.203mm

Intake 0.10 – 0.15mm (0.0039 – 0.0059″)
Dec2017: L 0.102mm, M 0.102mm, R 0.127mm
Jun2018: L 0.127mm, M 0.127mm, R 0.127mm
Dec2018: L 0.102mm, M 0.127mm, R 0.127mm
Shims: L 1.76mm, M 1.73mm, R 1.72mm
New Shims: L 1.72mm, M 1.72mm, R 1.70mm
Jan2019: L 0.152mm, M 0.127mm, R 0.152
Jan2020: L >0.127mm, M 0.127mm, R >0.127mm
Mar2021: L >0.127mm, M 0.127mm, R >0.127mm

Aug 18: Backed off pilot air screw ~1/4 turn to address hanging idle and tough warm starts (although we weren’t following the procedure in the manual)

May 2020: Unscrewed pilot air screw a little ~1/16 turn due to a bit of popping on decel.

To Do List

  • New front brake pads?
  • Replace upper rear shock bearing – got a set of bearings but there isn’t much play at all, probably install them next winter

Completed Tasks

January 2020

  • Check valve clearances

June 2019

  • Replace broken ASV clutch lever screw – Josh picked one up from TSR

Feb 2019

  • Oil and filter change – AMSOIL synthetic

Jan 2019

  • Re-fill with coolant
  • Install new head gasket
  • Check piston and con rod, visually inspect crank – looks good
  • Check valve clearances
  • Repacked muffler

Before 2019

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Getting the YZ250F ready for 2023

Since we didn’t get out on the dirt bikes at all last year, I’m determined to go up to MotoPark at least once this year. The older kids are both over 18 so I don’t need to provide bikes and equipment etc for them, I’d love for them to come […]

KYB Fork Protector

Fork Protector printed

One of the fork protectors was missing off the 2007 YZ250F and they are about $25 for a new one.  I figured I’d design and print one and see if it would stay in place on the track. Quick model drawn up in Onshape. Printed in PLA for now simply […]

Yamaha KYB Fork Cap Tools

I needed to replace the fork seals on my 07 YZ250F and didn’t have the special wrench for undoing the fork caps so I designed this tool to be 3D printed.  It took a few iterations to get the design strong enough but I was successfully able to loosen both […]

Dirt Bike – Repair Dent in Exhaust


2 Stroke Through a recent trade, a KTM 125sx was acquired with a huge dent in the exhaust.  Dents like this, not usually as bad are very common on these exhaust expansion chambers and while the bike might seem to run ok, a dent this size must be having an adverse […]

3 thoughts on “2007 Yamaha YZ250F

  1. Before removing the forks to change the fork seals, it is best to loosen the cap on top. On these forks that requires a special tool, a large octagonal wrench. These can be bought for about $30 but I was convinced that I could design a tool that could be 3D printed. After a couple of iterations and several hours of printing, the tool in the pic worked a treat! Both caps are now loose and the forks are ready to be removed.

  2. First time out at the track I had the lad ride the 4 stroke as I figured the smooth power delivery would be easier for him to cope with. He did excellent, only had one little fall in a corner and was soon hitting some decent jumps. When he tried the 125 SX on the next outing, he came back with a huge smile on his face and said “I want to ride this, we’re trading”! I rode the 125 SX exclusively on the first outing, and loved it, I wasn’t overly keen on even trying the 4 stroke but after a couple of laps on it I was sold! The YZ250F handles great and gives confidence over the jumps with the smooth power, vastly superior to the old 2001 YZ250F I had. There is a harsh double on one section that I daren’t attempt on the SX but after a couple of laps on the YZ, I went for it and cleared it no problem! The only bit of concern now is the reliability, the experience with the 2001 dropping a valve has shaken my confidence. It sounds a bit rattly to me especially when you shut off the throttle but I’m not sure what is ‘normal’ for these.

  3. Out at the track again yesterday, bike ran great! Only minor thing was that the gear shift lever worked loose – same on the KX100 weirdly?? Oh also the front end washed out a couple of times but I think that was rider error.
    I was nailing some of the jumps and doubles but still jibbing out on the big ones. The old RXR inflatable body armour I picked up was nice and comfy, not too bulky.

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