06 Yz450 No Oil Showing On Dipstick

5 replies to this topic
  • ashley65

Posted June 03, 2008 - 08:46 PM


While changing oil in a friends 06 YZ450, I noticed that there was no oil showing on the dipstick. I added a little and still nothing. I checked the oil pressure bolt on the head and it had good pressure. I checked the return line and it is pumping back to the tank. Drained the oil and refilled with the proper amount. Still nothing. Called him and he said it has never shown on the dipstick since new. Bike has about 20 hours. I have looked through the forum and have found where others have had the same problem, but noone has responded with an update as to what the problem actually was. My question is: Has anyone that has seen this problem before figured out what was the cause? I have owned several 06-07 YZ450s and have changed the oil in them hundreds of times, so I am sure it is nothing I am doing wrong. Thanks, Wes

  • Justin89

Posted June 03, 2008 - 09:17 PM


Start it after you refill it with the proper amount of oil. Mine does the same thing...for some reason the bike needs to start first. I'm sure theres some technical reason for this but IDK it lol. Make sure to let it sit for a min or so before you check it again otherwise oil will flow out through the dip stick hole. :thumbsup:

  • grayracer513

Posted June 03, 2008 - 09:42 PM


How is it that you "checked the return line" ?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • ashley65

Posted June 03, 2008 - 09:57 PM


I removed it at the top and started the bike. When I saw that it was pumping oil I immediately killed the engine.

  • grayracer513

Posted June 03, 2008 - 10:31 PM


There is no external oil return line on an '06 YZ450. If you removed the soft line at the top of the tank, that line is a simple vent between the primary case and the oil tank to balance pressure between them, and it has no direct connection to the oil pump or any part of either oil circuit. The only reason oil would come from that point is crankcase pressure pumping stray oil.

The return passage runs out the left of the crankcase into the left crankcase cover and is routed up to the front of the cover next to the dipstick. To see if oil is returning, you could run it with the dipstick out, but that would make a mess. Dry the stick and start the engine, it should come out wet.

  • ashley65

Posted June 04, 2008 - 08:07 PM


grayracer513, Thanks for the insight. I removed the left cover and cleaned the passages. I also blew air through the rubber equalizer vent tube, and when I reassembled and filled it with oil it worked perfectly. I don't know what was different because I found no smoking gun, but something fixed it.
Thanks again, Wes

Related Content

WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

05 yz450f not fast enough by RedeyeYZ

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  38 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.