Dirt Rider Magazine

Is it pre mix or the tranny oil?

Isn't that pretty normal for a two stroke? I know my old YZ250 did that. It ran down almost the full length of the exhaust by the end of a ride. I guess it depends on how much is oozing out.

more than what should be comin out......no it wasnt doing this before rebuild

crank seals and bearings are brand new

I mean drippin out of the head.....right where the exhaust pipe goes on

How 'bout pic(s)?

Tranny oil from the cylinder? You need to talk to whoever did the bottom end... and smack em. :)

Yeah, thats what I was assuming.

why? whats that mean?

i fill tranny up to where runs out check bolt on side. start it up blows white smoke an tranny emptys into cylinder. either seal or not sealing halves togather. i cant tell wat or witch one it is 4 sure.

I did tear it apart....cant tell where its comin from....it doesnt take long the piston probably goes up and down 4 or 5 times, so maybe a minute. this is my first time doing the bottom end. Using Moto1 sealant for the case halves.

I dont know how to post pics. I've already got it torn down again.....

I dont know how many times it goes up and down in a minute....was using it as an example

i'm sendin, now, i only have the left side off

Ok thanks!!

2 much mountain dews ur problem..

It's Moto1. What's the difference between yamabond and moto1?

what do you use?

when u put it on do u wait before putting them together or do u put it on and slap them together? The directions say to apply and then wait 1 minute and then bolt parts together using normal specs. but ive done that and it isnt working. also how much is too much? the first time i did it i put it real thin and i was told it wasnt enough, so the 2nd time i put it real thick (hence the mess) and that didnt work either. :?

Check and make sure your bearings are seated as well.

That was a general gasket/sealer/rebuild statement. :)

The only way you can have gear oil making its way through the crank cavity and up through the cylinder is if the crank case seal is blown . OR ... The oil seals that cover each crank bearing are worn bad enough to allow that much oil to come through. If your mixing your fuel way too rich it will definitely drip from the exhaust can and also blow out where the header connects to the cylinder. A good ratio to start with has allways been 32:1, mix 1 gallon and run it then maybe try leaning it out slightly. But remember ...check your sparkplug often , you want your sparkplug to allways be the color of a brown paper bag . Not black (= too rich) ,,,,,,,and definitly not white ,,,(= too lean and ready to blow) hehe... they allways seem to sound the fastest right before that last POP! :o A word of advice ,,,the guys that might tell you they run their 2-strokes at 40:1 and higher , are usually the guys that go through alot of top ends. A stock Yamaha piston and rings for that bike and year are inexpensive and will last an entire summer if not longer , IF ,you get the correct mixture , the correct jetting and and replace the leaky seals and gaskets. When you pull the top end apart , everything should be finly lubed , not flooded with oil. Many premix's these days are red and many tranny oils are also red , so it comes down to leaning it out SLIGHTLY, and if that doesnt solve it, chase down the leak. Besides , the bike wont spark at all if its flooded with tranny oil.Where are you located ?Im a mechanic for one of the top amature riders in the state of texas and weve learned how to refine his YZ250 by trial and error and now ....hes pushin 51 horses and smokes the 450's .....hehehe ,,,dont hesitate to ask if ya have any more ?'s about that 250 Bud ,,,,good luck ,Lee ( Lgrawunder@rgv.rr.com)

Fastway knows his chit in MOP.

If you put correct amount of oil @(26)oz in bike an started it, At a idle for a few seconds It was pushing oil past crank seal lip. An up into cyclinder an out head pipe.I got a new seal an got it fixed up now with yamalube gasket maker.