OzVMX Forum

Marque Remarks => Yamaha => Topic started by: YZ250H on February 18, 2010, 07:05:33 pm

Title: O ring size - YZ465 - urgent
Post by: YZ250H on February 18, 2010, 07:05:33 pm

Hi guys,

Trying to get the crank seals replaced before practice day on Sunday and found that the O ring behind the primary cog on the RHS is missing :o :o.  I will try to get one from Yamaha tomorrow, but just in case - does anyone know the size of this o-ring ?

I assume the diagrams on Yamaha website are correct ???

Title: Re: O ring size - YZ465 - urgent
Post by: Viper666 on February 22, 2010, 10:01:10 am

If it's like the 125 you wont find an aftermarket one to fit. (Odd size in the thickness)
Bushman trick, put threebond around the groove and wait till it goes tacky before putting the cog on.
Not ideal but works.
Viper666

Title: Re: O ring size - YZ465 - urgent
Post by: YZ250H on February 22, 2010, 05:38:45 pm

Thanks 666.  I spoke to the guy up here in the yamaha shop.  He guessed (I think 29 x 3).  I will know in a few days as I have a Yamaha one on the way.  The 29 x 3 fitted will, so I think he was right.  Maybe a little thick if anything. 

Title: Re: O ring size - YZ465 - urgent
Post by: LWC82PE on February 22, 2010, 06:11:21 pm

i use this site to find o-ring sizes. I have got many, many books and catalogues on o-rings. If you cant find the size, i should be able to. I would say its a japanese standard cross section though
http://www.transeals.com.au/seals/o-rings.php?

 i would probably put money on it that it is a 29.40 x 3.10 japanese standard. 29 x 3 is german

next smallest japanese cross section o-ring is 2.4mm
 

Title: Re: O ring size - YZ465 - urgent
Post by: All Things 414 on February 22, 2010, 06:16:52 pm

I'm a little confused.  ??? Are we talking about the crank seal?  

Title: Re: O ring size - YZ465 - urgent
Post by: YZ250H on February 22, 2010, 06:43:39 pm

Nah Rosco,
There is an O-ring that goes behind the main gear on the crankshaft sealing off gases sneaking between the crank and the gear.

The bike performed well at full tilt and low down - still crap midrange and now (suddenly) a prick to start.  Once started all is good (unless you leave it too long).

414 and Billet YZ have suggested a few things to look at - just a process of elimination really  :-\.  I know it isn't crank seals now.

Title: Re: O ring size - YZ465 - urgent
Post by: All Things 414 on February 22, 2010, 07:42:33 pm

Ooops! :-[

Title: Re: O ring size - YZ465 - urgent
Post by: YZ250H on February 22, 2010, 08:10:57 pm

Rosco I don't know where you are getting those pictures from, but please, please stop :P.  How about some good looking chicks just to mix it up a little  ;)

Title: Re: O ring size - YZ465 - urgent
Post by: All Things 414 on February 23, 2010, 06:44:20 am

I reckon' they're 'horn-bags'.  :)

Title: Re: O ring size - YZ465 - urgent
Post by: YZ250H on February 23, 2010, 07:48:47 pm

In case anyone give a rats arse the yamaha one looks to be 29 (maybe 29.5) x 1.5 measured with verniers