MORE random pics......

[GH85Carrera]

[sammyg2]

Mayday parade in the USSR

[sammyg2]

[GH85Carrera]

[RoadRaceJosh]

Originally Posted by sammyg2

Lemme guess, had a bottom end vacuum leak that caused it to run lean?

Piston design tells me that's not a 2-stroke-cycle engine. Looks like Subaru to me.

[craigster59]

[GH85Carrera]

[GH85Carrera]

[GH85Carrera]

[GH85Carrera]

[GH85Carrera]

[GH85Carrera]

Whoopsie

[svandamme]

Originally Posted by RoadRaceJosh

Piston design tells me that's not a 2-stroke-cycle engine. Looks like Subaru to me.

Nice 1st post on the forum..

but i don't think anybody here was saying it was a 2 stroke anyway.
And as far as bottom end vacuum leaks, i don't think there really is such a thing.. a vacuum leak is a vacuum leak.. a crank case technically should(doesn't have to be) not be vacuum ..

The only reason it typically would be vacuum, is for enviromental reasons, because those require the crankcase breather to vent into the intake..
and it typically does that through the vacuum plumbing.. And that's what causes the crankcase to have vacuum..


Any air escaping in the crank when it should not, will affect the vacuum system.
Which might cause unmetered air to go into the intake, and cause a lean running condition..

That has nothing to do with 2 stroke at all..

[GH85Carrera]

[GH85Carrera]

[Racerbvd]

[RoadRaceJosh]

Originally Posted by svandamme

Nice 1st post on the forum..

but i don't think anybody here was saying it was a 2 stroke anyway.
And as far as bottom end vacuum leaks, i don't think there really is such a thing.. a vacuum leak is a vacuum leak.. a crank case technically should(doesn't have to be) not be vacuum ..

The only reason it typically would be vacuum, is for enviromental reasons, because those require the crankcase breather to vent into the intake..
and it typically does that through the vacuum plumbing.. And that's what causes the crankcase to have vacuum..


Any air escaping in the crank when it should not, will affect the vacuum system.
Which might cause unmetered air to go into the intake, and cause a lean running condition..

That has nothing to do with 2 stroke at all..

Oops, blew the rule on my first post! Semi-random picture below!

With 2-strokes the air/fuel/oil mix travel through the crankcase. If you get a leak in the crankcase (bad crank seals are a common culprit) it will lean out the mixture and then you can melt down a piston. I believe this is why sammyg2 made the comment: "Lemme guess, had a bottom end vacuum leak that caused it to run lean?" The valve reliefs in the surviving piston shows it's no 2-stroke, however.

[svandamme]

Well i explained in my post that vacuum leak can cause lean running 4 stroke engines , and when a high comp 4 stroke engine runs lean, it can cause among other things, detonation.

Again, nobody said anything about 2 strokers, and the comment about vacuum in the bottom end did not automatically imply 2 strokes either because the crank breather ties into the vacuum system of most 4 stroke FI engines.

[GH85Carrera]

[GH85Carrera]