Transmission Lube Spooging out of Breather tube

I have a '99 kx250. the bike runs awesome, but I notice it spooges a lot of trasmission lube out of the transmission breather tube located on the backside of the kickstart housing. I use Maxima MTL 80w tranny lube by the way. Why do you think my breather tube spits out so much fluid? (I have to top off with about 1/4 quart every 3-4 hours). is this normal?

When you say "top it off", are you filling it up to the edge of where the oil goes in??

Are you aware of a sight glass window on the side of the engine case??

What quantity of oil are you using?

The KX250 holds about .9L of tranny oil or just a bit less than a quart. I usually put the whole quart in and have never had any oil drip from the vent hose. Are you putting too much oil in the tranny?

When you say "top it off", are you filling it up to the edge of where the oil goes in??

Are you aware of a sight glass window on the side of the engine case??

What quantity of oil are you using?

The KX250 holds about .9L of tranny oil or just a bit less than a quart. I usually put the whole quart in and have never had any oil drip from the vent hose. Are you putting too much oil in the tranny?

I am putting in .85 of a liter just like it says. this puts me right in the middle of the sight glass with the bike perfectly level. by "top it off" i mean up to the middle of the sightglass, not all the way overflowing out of the fill-hole.

why does my bike like to spit it out?

I am putting in .85 of a liter just like it says. this puts me right in the middle of the sight glass with the bike perfectly level. by "top it off" i mean up to the middle of the sightglass, not all the way overflowing out of the fill-hole.

why does my bike like to spit it out?

the only thing i could think of would be that the engine is pressurizing the tranny, most likely through a crank seal. thats a weird one.

^ could it be the lube i'm using?

think of it as your stomach. it doesnt like anything then i goes out of the back hole.

^ could it be the lube i'm using?

no, why would it

the only thing i could think of would be that the engine is pressurizing the tranny, most likely through a crank seal. thats a weird one.

I was thinking a preesure problem but could not see how. maybe the case halves have a leak but that would also suck in oil and burn it as well.

I was thinking a preesure problem but could not see how. maybe the case halves have a leak but that would also suck in oil and burn it as well.

thats kinda what i was thinking, but you never know, sometimes a seal will only fail in one directions

maybe it is sucking/burning some and leaking some? or like sean had said the crank seal is leaking outward and pressurizing the crankcase thus blowing oil out the breather.

no, why would it

well, perusing through some different sections, I saw that some 4t guys were having the same problem i'm having with a maxima oil product and once they switched to another brand it stopped. i'm gonna try switching to motul for a bit and see what happens. i guess some oils will kind of vaporize when they get hot more than others which makes them spit out the tube.

I was thinking a preesure problem but could not see how. maybe the case halves have a leak but that would also suck in oil and burn it as well.

i put a new bottom and top end (hot rods bottom end, wiseco top end) on the bike 40 hrs. ago. it runs super strong, starts right up and doesn't spooge much at all. the transmission and clutch work flawlessly. all the seals and bearings were also replaced with new during the rebuild.

in addition, the bike was spitting out oil even before the rebuild (old seals and bearings)

i ain't crackin' her open again at this point, thats fo sho!

I think youre missing the check valve or the case hasa leaK.

Might need a new part number 92005-1210

I think youre missing the check valve or the case hasa leaK.

is the check valve the part number this (see below) guy is referring to? the little metal insert with the hole that the hose connects to? if so, mine is new. could it be possible that I pressed it in with the hole facing the wrong way? should it face up or down or what?

Might need a new part number 92005-1210

i have a new one of those already installed. problem still exists.

well, perusing through some different sections, I saw that some 4t guys were having the same problem i'm having with a maxima oil product and once they switched to another brand it stopped. i'm gonna try switching to motul for a bit and see what happens. i guess some oils will kind of vaporize when they get hot more than others which makes them spit out the tube.

maybe in a 4stroke that has overheating issues, but a 2 stroke crankcase doesnt get hot enough to flash off oil like that. just use some cheap atf type f.

^ thanks jeekinz! it appears the hole faces up (because i can't see it).

pointed the hole up and it looks to be only letting out a drop here and there now!! good stuff :ride:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now