Where’s my oil going ??? (UK)

4 replies to this topic
  • Amyas

Posted January 24, 2007 - 09:31 AM


I have a WR400F and none of the oil is being returned to the frame via the outlet by the gear shift.
I’ve loosened off the banjo bolt on the head and this leaks oil, so it looks like the pump is working.
Any ideas ?

I’ve been told that it’s possible an O ring between the two crankcase halves could have disintegrated and neatly wedged itself somewhere inaccessible.
Could I blow it out from the outside and flush the system or is it an engine strip down.
Alternatively, I could fill the engine with sulphuric acid and leave it a few days …….….

  • Murray Dorward

Posted January 24, 2007 - 09:55 AM


Instead of using sulphuric acid, why dont you try and get hold of some nuclear waste from the local nuclear power station and you should beable to get the same result as sulphuric acid in about 2 minutes. Either or you will f@#k the engine up. As for the oil I have now idea.

Good luck with your cocktail


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  • Rich_in_Orlando

Posted January 24, 2007 - 11:46 AM


Are you absolutely sure about this? You probably already know this, but if you check the oil level after the bike has sat you won't find any oil on the dipstick. The engine has to be warmed up 3-5 minutes before checking the oil.

Ok, if that's not the answer, here's what I would do. First, check the oil strainer coming out of the frame. You never know what's going on with that. If that's not it, take off the outside oil return line you describe above. Blow it out to makle sure there aren't any clogs. Then, start the motor and see if oil flows out of the hole. It should shoot out. If not, then you have an internal problem.

Are you serious about the acid? Good lord, man! The other option would be to split the cases and see what's going on.

  • Amyas

Posted January 25, 2007 - 02:49 AM


Thanks Murray, Rich,

Getting the job done in 2 minutes would be great but my local power station wouldn't give me any waste. As for the Sulphuric Acid.... I don't want to spill any on the garage carpet.

I did take off the oil return pipe from the bottom next to the gear shift and ran the engine, but nothing is coming out. Almost certain there's a blockage between the pump and the outside.

I think you're right Rich..... a split case. Just wanted to know if anyone had experienced this and found a way of sorting it out.

Thanks guys

  • Murray Dorward

Posted January 25, 2007 - 07:03 AM


Pitty about the nuclear waste I think the pictures that you would have posted on thumpertalk would be something else. Jokes a side. Try compressed air but if you have no luck I agree with Ray split the casings and clean everything out properly with compressed air and parrafin and make sure all the oil lines are open. Your owners manual should have a daigram in it showing where all the oil channels are. If you dont have the owners manual try www.yamaha-motor.com.au and go to "support" and open "view owners handbook" you can download the owners manual on a PDF format.

Hope this helps

:ride: :ride: :ride:


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