99 yz400f fuel valve question

5 replies to this topic
  • mediumdaddy

Posted August 03, 2012 - 09:41 AM


Does the fuel valve on this bike have one of those crush washers in it? (i dont know if thats the right name, but thats what i call them) Those thin wavy metal ones? My valve is leaking pretty bad, so i got online and checked a diagram on rmatv, and i also checked my service manual, but i couldnt see one on either. The only reason i'm asking is that all the others of those i've taken apart have had them. I've got a new o ring and valve packing for it. If it does have one, what order do all the parts go back together on it?

  • grayracer513

Posted August 03, 2012 - 04:18 PM


If I were you, I'd buy the whole replacement petcock assembly with a new gasket for $15 from the TT store and be done with it. If you do it yourself, the packing goes first, then the O-ring on the handle, and the plate holds that down. No wave spring. You have a 50/50 chance of successfully resealing it.

  • mediumdaddy

Posted August 03, 2012 - 04:56 PM


Why only a 50/50 chance?

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  • grayracer513

Posted August 03, 2012 - 06:57 PM


It's one of those little things that turns into a frustrating exercise in futility more often that not. They're just a real pain in the butt to get resealed once they start leaking, and it's altogether too easy just to replace them at that price, even for an old skinflint like me.

  • mediumdaddy

Posted August 03, 2012 - 07:13 PM


Well that is fair. I already bought the guts or id buy the whole thing. I may leave it for now to as if i back it off about an 8th of a turn it stops leaking and the bike runs fine. I dont know.

  • mediumdaddy

Posted August 27, 2012 - 10:21 AM


OK so! i've changed the guts of this thing, and it doesnt seem to be leaking, yet, (cross fingers) but it is really tight and almost impossible to turn. normal? i'm assuming not, but if i back the screws out at all to loosen it, the handle hits, so i think ima just leave it on. it doesnt leak after all. what do you think grey?

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