I was warming the old girl up the other day before a ride. Rode it around the yard and when i parked it to finish getting my gear on i noticed that i had a hole blowing oil out of my head....
It is right above where the exhaust comes out and i looked on a friends YFZ and it has a rubber plug it the hole and i guess mine blew out. Has anybody else heard of this happening to a YFZ i have no clue what this plug or whatever it is does. If you have any information that would help me out please post. It still runs but its blowing oil out of this hole.

 

Get with 250r4life. He had the same thing happen to him. He should have the part number for it.

 

The part number you need is 90338-18064-00 and runs about $3.00

I have seen this happen on the dirtbike but not the quad.

 

LOL - Wife and I were just talking about this!

Friend's Wife had it happen on her YFZ over MLK weekend at Glamis. Thought she blew the engine [img]i/expressions/face-icon-small-shocked.gif[/img] She was at the starting line and Ilook over and see a ton of smoke coming from her quad. Guy lined up next to her pointed out the smoke and she quickly rode it over to us. Didn't take long to see the pipe was missing a bolt on the head AND there was a freekin' hole in the head! Looked around for what it was connected to then went over to another Y to find it was a plug. When I got home I looked at my YZ426 and realized it was for the cam de-compressor. Why Yammy couldn't make a new casting to FIX the hole is beyond me (Freekin' STUPID!) Correct me if I'm wrong but, the YZ450, WR450 and the YFZ450 which all use this head don't have a manual decompressor anymore? Why do they still make this in th casting? Even if one of the bikes still has the manual de-compressor they should have a different casting for the bikes that don't.

Don't buy one of these plugs. . . buy two! A $3 part is a $hitty way to kill your weekend.

 

www.gtthunder.com $19.95 they sell an aluminum plug w/ a retaining bolt. Much better. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Yep that's my thread over at YFZ central. It happened to me. I Don't know why. I put another one in my bike & it hasn't happened again. I bought a couple plugs incase it happens again.

 

I bought three....[img]i/expressions/face-icon-small-disgusted.gif[/img]

 

Well if someone has already bought 3 @$3 ea, that's already half way to the $19.95. Fix it half-a$$ or fix it right, pretty inexpensive for piece of mind. For those that don't know, GT Thunder is one of Bill Balance's sponsors, reputable shop.

 

They are only reputable if it isn't about dynos! LMAO sorry... had to.

 

Good Post. i like these...look out for this stupid $3 part it can destroy your weekend type posts. i'm pulling mine today, adding Yamabond. and ordering a backup for the tool box.

Q. will you need Cam decompression if you switch to a kickstart? this could be the reason for it existance.