Oil pump

5 replies to this topic
  • finthat

Posted April 24, 2009 - 06:47 AM


One more issue. Has anyone ever had the oil pump sieze up?? I bought an '03 with a blown engine. I was ready to put it back together and decided to pull the oil pump to inspect and clean it. The pump was trashed. The larger outer rotor was broken along with the pin and inner rotor. I figure when the bearings and gears started flying that a piece got in and jammed it. I now have a used pump but the outer rotor doesn't want to drop into the case easily, there is signs of something being stuck in the case or that the old pump seized. I have been trying to clean it out with emry paper ect.

I guess my question is how hard should the rotor fit into the case and will i hurt anything by using emry cloth on the case??

  • grayracer513

Posted April 24, 2009 - 06:53 AM


If you are careful, and you clean up well, you can sand out minor damage in the rotor pocket. See page 2-9 of your manual. The rotor clearances are listed there. The inner rotor should have .003~.006".

  • finthat

Posted April 24, 2009 - 07:36 AM


I looks like something got in there and is smeared to the wall. I can get the outer rotor in but it won't turn. When I remove it I can see where the bind points are.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted April 24, 2009 - 08:12 AM


Try to use a set of curved "jeweler's" files to work down only the high spots around the gouge, and if you can see that there's a piece of steel jammed into the case, try to pick it out.

  • finthat

Posted April 24, 2009 - 08:49 AM


I have it so I can turn the pump with a screw driver prying on the drive gear. I can't get it to go by hand yet. I was thinking of using a propane torch to heat up the housing to see if there is a thin layer of steel in there it may turn red and peal off easier. Not sure. I may just keep trying to slowly work it by hand. The rotor wouldn't even fit before.

  • grayracer513

Posted April 24, 2009 - 09:08 AM


The oiled outer rotor should drop in and spin easily with one finger.

Related Content


yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies

100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Is the 2016 GYTR Yamaha YZ450F too fast? by Fryboy

Dirt Bike   Special Interest Forums   Pro Racing
  • * - - - -
  • Hot  241 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

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.