First 4 stroke rebuild experience

5 replies to this topic
  • coastlinecascott

Posted January 03, 2016 - 08:09 PM


No longer intimidated by a 4 stroke. I took my project 2008 yz450f down to the last nut and bolt. Also removed all the valves replaced all valve seals and cleaned the head. Valves were still sealing. The piston, crank and bottom end bearings replaced. In about 25 hours im sending the head off for new seats and recut and replace the valves.

For the people that are scared of a 4 stroke. They are super simple to rebuild with a manual. The hardest part was doing the torque on the head bolts. The 180 degree turn was hard with the motor out.

Make sure and order a hot cams shim kit and a offset feeler guage.
Overall fun easy project.

  • vossman23

Posted January 04, 2016 - 12:35 PM


How much did this set you back? I have a 09 450F that's got about 75 hours on it so it's gonna need a refresh here soon.
I'm not ready to rebuild a 4 stroke yet. I bought an old 2 stroke I'm gonna start on. 92 YZ250 that's in ok shape but doesn't run.

  • coastlinecascott

Posted January 04, 2016 - 12:43 PM


I got the oem piston ring and gaskets from partszilla about $150 with head rubber gasket. Oem Crank was new ebay $325. Bearings and stuff i forgot. About $700 ish. Its really not hard to do. If your a techy person, its really a fun project. I even pulled the valves out to do a good cleaning. I removed and reinstalled them without a fancy valve tool.
I meant total was 700ish

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • vossman23

Posted January 04, 2016 - 02:39 PM


Nice. Can you tell a difference in how it runs.

  • coastlinecascott

Posted January 04, 2016 - 03:24 PM


It stopped running on me in mid flight. Iy jumped timing. Luckilly no damage. It was from an overused cam chain. I have not run it at the track yet.

  • kawasaki_873

Posted January 04, 2016 - 03:32 PM


hopefully you cut new valve seats for the new valves.

opps sorry I missed that you said you was sending the head out, sorry my bad. glad you did!

Related Content


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.