2003 YZ 250 Power Valve not connected

[WCA]

Over the weekend I pulled the case off to rebuild the water pump.  When I pulled the power valve cover off I noticed that it wasn't attached to anything - see photo.  To me, the bike has always run great - I would have never thought the power valve wasn't connected.  I bought the bike used a couple of years ago and it is set up for the woods.  Is there a reason that the power valve might have been disconnected?  When I pulled the cover off, nothing fell out (like a screw, nut or whatever) so it makes me think it was intentionally unhooked.  Any thoughts?  Other than how damn dirty my engine is. 

[GCannon]

Looks like it vibrated loose, the collar you need on the outside of the arm is back in the corner near the case the screw and washer may be there too.

You need a new power valve shaft seal.

[MaybeMe]

1 hour ago, WCA said:

Over the weekend I pulled the case off to rebuild the water pump.  When I pulled the power valve cover off I noticed that it wasn't attached to anything - see photo.  To me, the bike has always run great - I would have never thought the power valve wasn't connected.  I bought the bike used a couple of years ago and it is set up for the woods.  Is there a reason that the power valve might have been disconnected?  When I pulled the cover off, nothing fell out (like a screw, nut or whatever) so it makes me think it was intentionally unhooked.  Any thoughts?  Other than how damn dirty my engine is. 

Looks like the PO didn’t put it together properly. You should notice a massive difference when it’s hooked up.

[bikedude987]

Also note the shaft retainer appears to be missing from the PV shaft.  

EDIT - maybe it's just dirty, looks like it might be there after all...

Edited January 29, 2018 by bikedude987

[YZDOC]

Only thing I can think of is PO forgot to put the bolt in when he re-assembled it. If it backs out, it will hit the cover and not come all the way out. Are there any whitness marks on the inside of the cover of this?

Would say, it will surprise the hell out of you when it's attached and you ride it. 

[WCA]

Thanks guys!  Looks like to have a little work to do.  How difficult is it to replace the shaft seal?  I woiuld rank my wrench skills as marginal at best.  I wonder if the PO disconnected it to tame the bike a bit.  The guy bought it from was the second owner and he told me he was selling because it was too much bike for him and he was scared of it.

[markmc2]

U better look over the whole bike closer. And that power valve will rock your world.

[Ryguy00]

Hooking that power valve up is going to take your bike from 125 4 stroke level of power to 450 4 stroke level of power. Basically, it's going to double the power you're used to when it hits. Be ready. Your bike is about to get a whole lot awesomer! Yes, I said awesomer.

Also as mentioned above, that's a huge red flag to start looking the rest of the bike over VERY closely. If you don't know what you're looking for, find someone who does to help you.

[YZDOC]

PITA with engine in or jug on bike. Super easy when the engine is out or jug is off.. 

6 hours ago, WCA said:

Thanks guys!  Looks like to have a little work to do.  How difficult is it to replace the shaft seal?  I woiuld rank my wrench skills as marginal at best.  I wonder if the PO disconnected it to tame the bike a bit.  The guy bought it from was the second owner and he told me he was selling because it was too much bike for him and he was scared of it.

 

[bikedude987]

My $.02:  Just reconnect the linkage for now (after ensuring the PV assembly moved freely - pull one of the side valve covers and make sure it opens when you turn the shaft all the way - shouldn't take much force), ride for a bit, then when you're ready for a top end, replace those two seals.  There's one in the cylinder and one in the clutch cover case.  The cylinder one is easiest, the case on you have to disassemble the whole PV governor linkage.

[WCA]

I like the way you are thinking, bikedude987!  In fact I was going to ask it the seal is a "must right away" kind of thing.  I shouldn't be too far from top end.  Right now I have a power valve gasket, power valve seal (the rubber boot thang at the bottom of the cover) and the screw that holds the linkage in place.  That will hopefully get me back up and going in the short term.  Thanks everyone for your help and input - much appreciated.  I seriously don't know how I ever fixed anything without TT and YouTube...