Gently Dropped - Oil Hydrolock & Recovery

[jtdiffen]

Arriving home in the dark I drove over a tree root and gently “lowered” my R9T to the left side crash bar. Turned it off and pushed it onto the driveway. No problem right? Wrong.

In the morning it refused to start/turn over with a noticeable “clunk” when the starter attempted engagement and refused to budge the motor.

Thinking this through, I decided to pull the left side spark plug to see if I’d hydro locked the engine with oil. Yup, poured right out.

Left side cylinder was clear and dry.

After a quick valve clearance check I put everything back together and she fired right up. Lots of oil smoke burning off but that cleared up after a few miles.

I just wanted to share this with the forum in case someone else was afraid they’d seized their motor following a similar incident.

All better. Baby’s back on the road.

 

[mikegalbicka]

Nice looking bike. Good job sorting it out and thanks for sharing.

 

[Omega Man]

Nice diagnostic work.
A little extra oil, much more betterer that water from the swamp crossing……full of slippery rocks!
OM

 

[DavidR8]

Seems odd that enough oil to hydro lock would leak past the rings in such a short time.

 

[98lee]

How long was the bike on it’s side?

 

[Omega Man]

It doesn’t take long, or much oil, for an oil lock if all the conditions are right. Head full, valve(s) open just right. Especially on a boxer style engine.
OM

 

[98lee]

Oil doesn’t go through the valves, it goes past the rings. Unless boxers don’t have valve guide seals.
I guess that’s an old picture (no crashbars).

 

[jefla]

I’m somewhat new to BMW and ride a 1250 RT without crash bars. Oil hydrolock is new to me. So, if one drops a boxer there’s a decent chance of this happening? Ugh. Roughly, how long does it take for enough oil to seep past the rings to cause this problem?

Thanks, OP. Really good to know.

 

[52184]

I’m somewhat new to BMW and ride a 1250 RT without crash bars. Oil hydrolock is new to me. So, if one drops a boxer there’s a decent chance of this happening? Ugh. Roughly, how long does it take for enough oil to seep past the rings to cause this problem?

Thanks, OP. Really good to know.

This is the first such incident I’ve ever heard of in 40 years of boxer ownership, and above in the thread there are several unanswered questions, like how long the bike was on its side. So I wouldn’t be too concerned over it. I’ve had boxer GS bikes on their side for a couple of hours while working to rig an extraction or get help with same (long stories), and never had a lockup as described in this thread. So, I wouldn’t be too concerned over it.

Water lockup, brought on by dropping a bike in the middle of a water crossing or charging through a crossing at too high a speed, IS a concern that needs to be heeded. But, I doubt you’ll be engaging in such antics with your new RT.
And older carbureted boxers were able to fill a cylinder with gasoline if the right conditions were met, like a stuck or failed carb float coupled with an intake valve resting at open and a petcock that was left on. But, still a pretty rare occurrence.

Best,
DeVern

 

[Omega Man]

This is the first such incident I’ve ever heard of in 40 years of boxer ownership, and above in the thread there are several unanswered questions, like how long the bike was on its side. So I wouldn’t be too concerned over it. I’ve had boxer GS bikes on their side for a couple of hours while working to rig an extraction or get help with same (long stories), and never had a lockup as described in this thread. So, I wouldn’t be too concerned over it.

Water lockup, brought on by dropping a bike in the middle of a water crossing or charging through a crossing at too high a speed, IS a concern that needs to be heeded. But, I doubt you’ll be engaging in such antics with your new RT.
And older carbureted boxers were able to fill a cylinder with gasoline if the right conditions were met, like a stuck or failed carb float coupled with an intake valve resting at open and a petcock that was left on. But, still a pretty rare occurrence.

Best,
DeVern

Pretty much a fan of this all encompassing explanation.
Enjoy your bike. Chances are if you end up in the situation you are concerned about, it would just take a little work and probably a set of spark plugs to get you back on the road.
OM

 

[pglaves]

Pretty much a fan of this all encompassing explanation.
Enjoy your bike. Chances are if you end up in the situation you are concerned about, it would just take a little work and probably a set of spark plugs to get you back on the road.
OM

True, but I do want to mention one risk to be attentive to. If, perchance the opposite cylinder fires and the affected cylinder then locks up the typical result may be a bent connecting rod. My cautious advice would be if the bike has been on its side any prolonged amount of time - then remove the spark plug of the downside cylinder and crank the engine a time or two. This might be a bit messy but beats getting a bent rod and damaged engine.