Engine Bolt

[Guest]

1980 Suzuki GS850G. The post that comes up from the engine right behind the starter and has a tube that feeds into the starter bay and into a hole in the engine. Is this some sort of crankcase breather tube? There was no gasket around the tube leading into the engine just a gaping hole. Anyone know what this is?

[AMK]

You are correct, its a breather, but for the secondary gearbox. Vents into the starter cavity through that gaping hole.

By the way welcome to the forum.

[bwringer]

The small tube is a vent for the chamber holding gear oil around the secondary drive gears.

The hole under the starter leads to a void in the casting that drains to the outside. It's just a drain hole, and it does not need a gasket or seal. The chamber holding the starter is not sealed, so this hole needs to be open so that rain water can drain.

If oil is coming out of your Mystery Hole, it's most often the o-ring around the nose of the starter is leaking -- a pretty easy repair.

We call this the "Mystery Hole" because it causes great anxiety and consternation for people who suddenly notice "there's a hole in my engine?!?!?!?!?!!!!????" and panic.

Here's the lower Mystery Hole in a scrap GS850 engine -- the blue tubing is only there to show that it's connected to the upper Mystery Hole under the starter.


Here's the view from the top. The small black vent tube has been sort of rotated out of the way.

[PeteRepete]

Thank you! definitely caused some anxiety as there was a bunch of dirt in the starter bay falling into that hole.