Oil blow back on 84 IC with kol twin series II

[Aahicnow]

update next day
Took machine out for quick run to day and had a bit of blow back on the engine cover above the fill tube. That is until i tried to climb over the snow bank that produce oil everywhere under the hood oil seems to be up again so i am assuming fuel in oil again.

Just read something in service manual, can someone clarify for me it says you should have a negative pressure on the dipstick tube( where it says to do mano test)which i do not i have positive pressure it is blowing out on the dipstick and the oil fill, This means that something has to be creating a vacuum. Is this what the rubber tube is suppose to do that runs to the breather? If this is the case any holes in this tube will decrease the amount of vacuum. If this tube is to produce vacuum,what stops it from sucking oil up into the air breather? Does the placement in the airbreather make a difference (ie closer/ further from the filter) This goes back to my problem with the cable obstructing here the hose is suppose to install see pic

[plott hound]

leaky crank seal,worn valve guides can cause preasure in the crankcase.i have a Honda generator that barfs oil out the crankcase tube.figured that a quicky ring job would solve the problem.i was wrong,it turned out to be one bad crank seal and 2 worn valve guides.

[curtisbyrne]

my friends 18 vanguard is doing the same thing....

[curtisbyrne]

maybe a blown head gasket?

[racerone3]

A 4 stroke v twin engine should have very little crank case pressure or vacuum. As one piston goes down, the other is going up, so there is about the same air volume at all times. If an engine had NO LEAKS, and the crank case breather was properly routed to the air filter there would be negative pressure at the dipstick. As an engine wears you start getting pressure leaking by the rings, and valve seals (in the case of a flathead engine like yours) which cause a bit of positive pressure. This is where a leakdown test is helpful. The breather assembly has baffles to keep oil out, and is located high in the block well above the oil line. all that should push out is the airborne oil vapor. Typically with the breather into the air filter, this vapor is burned off with the air/ fuel mixture. If you are getting fuel contamination, your oil gets thinner, and therefore vaporizes much easier.

[dirtdobber]

This is a longshot and perhaps a dumb question....but here goes. Does this problematic engine have any type of splash guard inside the crank case to keep oil, splashed about by the crank, from getting into the breather tube? If so, if the splash guard has broken or come loose could that be his problem? It sounds like his problem gets worse as he gets on inclines (see post 21). It sounds like his problem is worse than splashing, but just thought I would float this idea.

[Aahicnow]

Ok Racerone I am going to try hooking the breather tube back to where it is suppose to go,and put a new air filter in and see if this get rid if the positive pressure at the dip stick. I will just have to watch out for a stuck throttle. If rerouting if fixes crankcase pressure issue, i will then see about rigging something to prevent the throttle stick issue.

[wedge]

If I am rite there should be a filter in the vent plate. Like a webbing of sorts. I have seen them get oiled up pretty bad and if you take it out and wash it out then let it dry it should be good after install.
If you pull your dip stick out and it blows air out of the tube when you rev it then you may have bigger problems ??

[Aahicnow]

Got this straight out of service manual

If there is no pressure or positive pressure(at the dipstick tube (which i do have)) do the following,
a: crankcase breather clogged or inoperative:, Disassemble, clean reassemble, recheck pressure (in proccess I did try blowing air into the tube and it did exit out the filler tubeand dipstick so thinking not blocked, will reinstall in correct postion tonight )
B: seals or gasket leaking: (hope not)check for proper sealing of crankcase
C: Blowby or leaky valves: Check compression (Done 101 psi in each cylinder)
d: Exhaust restriction : Check Muffler (dont think i have problem here)

[ARGOJIM]

When cleaning the breather check all parts in the manual, the last Aegis I did (because it blew the cam seal out) has the fibre and a metal tongue which according to someone else can rust shut, break or move sideways so check that that is where it belongs if so equipped.