Topic: Can overfilling your oil cause major problems??? (on a 1976 550)

[liaudio]

Ok... Today, I took my alternate '76 550 out for a spin while my buddy was riding my k5 750.  We hit the parkway and I opened her up.  I hit about 105 mph (4th gear) trying to keep up with him and then let off the throttle to make the next exit. When we came to a stop my buddy pointed at my engine and shouted, "DUDE!!!  WTF???" 

I looked down in dismay.  It seemed as if someone had thrown a bucket of 20w50 all over my entire bike from the carbs back.  It was literally drenched, dripping, bad.  We pulled over, examined it, and couldn't see where it may have been coming from.  What I did notice was that I didn't have the breather hose that connects the top of the valve cover into the bottom of the airbox.  I never knew that you really "needed" that.  That was the only spot that looked like it was coming from.  The whole right side of the bike, (and a little bit of the left,) from the carbs back, was covered in oil.  Even though it was still hot and I didn't have a rag to wipe off the stick, I checked the oil to see if I could ride it back home, and it looked full. (I decided to trailer it home either way.  hehe. I don't really trust a machine that throws oil everywhere. Safety dance or not.)

Once I got it home and after it cooled, I checked the oil again.  I leveled the bike and pulled the stick.  It read about a 1/4 inch over maximum so I checked it again.  Same thing.  Hmmm...

1st question:  Can over filling the oil in a 550 cause it to blow oil from somewhere?

2nd question: Can oil blow out of the valve cover breather? Ever?

3rd question: Is there a PCV valve or something in the valve cover that needs some sort of vacuum off of the airbox to operate?

I started it up once home and couldn't see or hear anything wrong.  I revv'ed it briefly way up to about 11,000 rpm's to see if I could duplicate the oil leakage, but nothing happened.  (my neighbor did shoot me an evil glance, but that i'm not worried about.)

Hmm... 

Any idears?

Thanks guys!  You rock!

[Sam Green Racing]

Apart from a load of mechanical things, there are two other things inside your motor,..Oil and air.

As the motor gets hot, the air expands and has to get out, normaly through the breather on the top of your cam box.

If you have to much oil in there, it's going to want to come out with the expanding air as the pressure builds up.

Let some oil out untill you have the right amount in and conect your breather to the air box.

Sam.

[cafe75-550]

1st question:  Can over filling the oil in a 550 cause it to blow oil from somewhere?

Yes. As pressure builds up from the expanding oil and air it will have to find a way out, in this case, the easiest spot was the breather.

2nd question: Can oil blow out of the valve cover breather? Ever?

"Blow out" may be exaggerated, but maybe not under your circumstances. I have one of those breather filters (rather than a hose) on mine, and its "wet", the last time I took it off it was enough to get my hands oily.

3rd question: Is there a PCV valve or something in the valve cover that needs some sort of vacuum off of the airbox to operate?

Nope, no valve whatsoever. Just a hole in the cover, with a small splash shield if I remember correctly...

And like Sam said, just drain the oil back to normal levels and clean up your engine, should be ok, just keep a check on that oil level.

Hope this helps! 

[rhinoracer]

I'm no expert on 550s but if it's anything like the 750s it is a dry sump model so overfilling shouldn't cause your problem, maybe it's the oil pump check valve sticking.

If it's not like the 750, I HAVEN'T SAID ANYTHING!

[cafe75-550]

Wet sump! No oil tank! 

[Sam Green Racing]

If it's not like the 750, I HAVEN'T SAID ANYTHING!

 

[crazypj]

When was the last time you rode it? (previous to this episode)
If you didn't do a major overfill it may be gas leaked in over a period of time and raised oil level.
 Its doubtful you did any damage but it is possible to pull the top off a piston if it hydro locks (sump overfilled) or bend a rod (usually only if water gets in through valve)
There are no PCV type valves in the motor, just a hole connected to airbox.
Oil level should be half way between top and bottom marks on dipstick
PJ

[TwoTired]

1st question:  Can over filling the oil in a 550 cause it to blow oil from somewhere?

yes

2nd question: Can oil blow out of the valve cover breather? Ever?

yes. Your buddy even pointed it out for you! DUH!

3rd question: Is there a PCV valve or something in the valve cover that needs some sort of vacuum off of the airbox to operate?

No PCV valve.  There is a breather connection and element in the stock airbox that many people are eager to throw away.

You have a wet sump on the 550.  The crankshaft spins just above the oil supply,  If you fill to a level close enough the crankshaft, the air mass spinning with the crank will pick up oil from the sump and whip it into a froth.  Some engines have a windage tray below the crank to allay this, others have a dry sump to prevent it.

At high RPM, the rings are more likely to let some of the combustion gasses past the piston rings.  It's called blow by, and it pressurises the crankcase.  Oil froth plus pressure dumps oil overboard.  If the crankcase didn't have that vent on top, it would blow out oil seals.

So, why did you overfill the oil sump?  And, why did you think Honda put a hose on that breather fitting?

Cheers,

[crazypj]

 
bit harsh, but its late
PJ

[liaudio]

Thanks everyone for the help.  I will make sure that the oil level is where it should be.



And if I had noticed that the breather hose was missing, I would have installed it.  But thanks for pointing that out. 

[cb650]

Make sure your carbs werent leaking as it sat.




                      Terry