newb needs help!

[488hybrid]

hi all, i am new here and i am in need of some advice. i have a 2001 400ex with a 2005 crf450 motor, it ran great up till a week ago. my problem is my trans, oil is getting sucked into my crankcase side, i replaced the right side crank seal and the balancer seal on the left side, it ran good for about an hr then it started pukin oil out the breather tube. anybody have any idea what else it could be?

[blacknblue#2]

Your motor has "blow-by" If the seal didnt fix it them more than likely its in the top end. May just need a set of rings or your jug may be wore past tolerance. thats something you wont know until you get the top end off. Basically whats happening is your compression is getting blown past the piston into the crankcase causing pressure which in return forces the oil out through the breather

[488hybrid]

that would cause my trans. fluid to go into the crank side? i will run a leak down test and comp. test. the top end has only 11 hrs on it. i'll check it out thanks!

[blacknblue#2]

I guess i should have read th post a little more clear. I mainly just read where it was puking oil out of the breather tube...If its draining the oil completely out of the tranny side and into the crankcase it seems like your seal should have fixed it....There is a reed valve between the cases that alot of ppl will try to tell you seperates the tranny and engine oil but that aint fully true. That reed valve releases oil out of the crank chamber when the piston is on a downward stroke. So dont let someone talk you into splitting the cases over a 3 dolar reed valve that in gonna fix your problem......and a leak down test wont hurt either way just to rule that out

[488hybrid]

the leak down was good and my comp. is 156. i ordered .5mm thicker seal for a 2008 crf 450 and give it a try. the seal i put in it looked a lil off in the journal so i will try it again and let ya know!

[488hybrid]

put new crank seal in from a 2008 crf450 new balance shaft bearings and seal fired it up and ran it for about 7-10 min and it still leaks trans oil into the crank side! any other ideas on what i can do? i am lost!

[JAG Motosports]

broken case is about all thats left .... i have a crf250 not a 450 does the 450 have a collar on the crank and the seal

[488hybrid]

no it does not have a collar on either one! when i rode it last, the crank case side was way overfull of oil! the next day i looked in the sight glass and it was down to normal, so i rode it again today for about 10-15 min. i noticed oil all over the side of the stator cover.(i took the breather hose off) again crank side way over full. i guess i will have to split the cases and see if they are broke or cracked somewhere!

[488hybrid]

no it does not have a collar on either one! when i rode it last, the crank case side was way overfull of oil! the next day i looked in the sight glass and it was down to normal, so i rode it again today for about 10-15 min. i noticed oil all over the side of the stator cover.(i took the breather hose off) again crank side way over full. i guess i will have to split the cases and see if they are broke or cracked somewhere!

[488hybrid]

ok i pressurized the trans. side with 3lbs of air and oil started to bubble on the left side behind the flywheel around the crank seal.

[488hybrid]

not the crank seal! its leaking out where the reed valve pushes the oil back out. so either its a bad gasket or with my luck a cracked/broken case!