first 2 stroke

**fatcat** · 07-02-2007, 08:30 AM

hi everybody i bought a1994 yamaha yz 250 yesterday i think.
i need to know what year it is the vin is jya4jxw07ra010400
it has a leak around the power valve its pre mix
also the shift shaft is leaking was told an o ring would fix this??
how do i fix the leaks?
how much oil is supposed to be in the tranny?
other than the leaks it is in great shape runs

**J.D.** · 07-02-2007, 01:10 PM

Where at around the powervalve? On a cover, or out of the pipe etc? If it's just a cover for it, replace the gasket! As for the shift shaft, take the shifter out, use a pick or something similar to take out the old seal, and pop a new one on being careful not to damage it on the splines. I couldn't tell you how much oil for sure should be in the trans, but it's usually a 1/2 pint or a pint or so. There will be a bolt on the same side you fill it that you take out, and when it gets full, it will drip out of the bolt hole. good luck!

**rot box** · 07-02-2007, 01:53 PM

94 was a really good year for the YZ 250

also when replacing the shifter seal trow the new one in the freezer for about a 1/2 hour or more that way it will shrink alittle and it should slide right into the case. And put a light greese around the case, and shaft.

Be sure to put in a quality gear oil ~ 80W should be good (not 10W 40)... Definatly not any more than one quart

Good luck,

Andrew

**fatcat** · 07-02-2007, 04:03 PM

i got maxama 70 weight
ill replace the seals soon
got to looking and it has a pro action forks and shocks

**J.D.** · 07-02-2007, 04:05 PM

hey Fatcat, where in TN are you at?

**fatcat** · 07-02-2007, 09:33 PM

celina why?

**fatcat** · 07-02-2007, 09:56 PM

found out it has an excell rear rim also

**fatcat** · 07-02-2007, 11:10 PM

and front rim. possibly boysen reeds

i took the header off to paint and looked at the piston has very light score marks on it. there has to be oil on the spot your looking at or you cant make them out easily .
is this normal? i would like to catch everything early rather than it blow up on the trail.

**jason 32** · 07-02-2007, 11:33 PM

dont put the seal in the freezer-
put a piece of plastic- garbage bag/ sandwich wrapper-ect... around the shift shaft- add a lil oil or grease, and slide the seal over the oiled plastic cover ,and it will slide easy ,and keep the splines from damaging it-
use a deep well socket to push the seal all the way in-/ make sure it goes in straight

dgy yamaha is cheep on parts -im pretty sure

**fatcat** · 07-03-2007, 12:06 AM

thanks for all the help
the piston worries me still.

**rot box** · 07-03-2007, 12:31 AM

The only real way to tell the condition of the piston is to pull the whole top end. That being said (IMO) if it has good compression I'd run it...

If your wanting to double check everything I'd definatly go through the suspension (it's often overlooked) I'd clean, inspect, and grease the rear linkage, and change the fork/shock oil. On a used bike you never know...

BTW: Post some pics it sounds like a pretty sweet bike

**fatcat** · 07-03-2007, 01:03 AM

heres a pic. not much to look at but for $960 im not complaining. it runs great
i would go through everthing but i dont have the money or time really
ordering parts

dads paying for it to
getting a skid plate and shifter looking into graffix and a seat cover
how do you repack the silencer?

**Bryan Raffa** · 07-03-2007, 07:11 AM

yep 94 for shure

**rot box** · 07-03-2007, 12:58 PM

For under a grand!

**fatcat** · 07-03-2007, 02:24 PM

well was it worth it?
i think so. i was smiling all the way home
o the power

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