'81 GPZ550 Oil Seeping at Barrels / Block Joint

Hi All,

in a 100 mile ride I have to wipe the oil off of one side of the engine per photos. It seeps a little from the other side too, but barely. Seems to be coming from the base gasket near the front block stud or the similar looking boss that is not a stud just under the O553L in the casting. I am guessing this might be 'typical' for a 38K motor that has never been opened. Any first hand knowledge of an easy fix would be much appreciated. I am guessing I have 3 options:
1. Wipe regularly.
2. Re-torque head bolts after shooting a little carb cleaner into the joint to clean it and applying a wicking sealer (and possibly sacrificing chicken).
3. Replacing the base gasket (see #1 above).
Looking for some experienced GPZ550 advice. TIA,
Bill

Just did this last month on my 42,000 mile gpz550. You will want to replace the head, base and valve cover gaskets. Also, the four oil gallery O-rings. I also lapped the valves and replaced the valve guide seals. Also the tachometer gear guide oil seals. On mine, I replaced both of the camshaft chain tensioner springs and O-ring seal. For good measure, I also replaced the mission cover gasket and seals. Mine had good compression and did not use oil, so the piston rings were left alone. Any doubt of the rings on yours and would recommend replacing. On mine, the base gasket had completely disintegrated and was leaking the most. Good luck!

Not a good idea to put used rings back in, they bed into the bores and never seal up as well when you resuse them as they do not go back into the same place ever. New rings need at least a scuff hone to bed them in. Only time this does not apply is to a Nikaseal bore, usually on a 2 stroke.

I reused the rings on my 1015 barrels and pistons. I gave them a light hone but was planning them to be temporary while I saved up for another 10.25/1 piston and four sets of rings, gaskets, etc. I did a valve job and it still burns a little oil. Not fouling but it still does. If I wasn't planning on a piston switch, I would have put in new rings.
Steve

Truthfully, this is generally a misunderstood thing and It really doesn't matter too much if you reuse the rings for a while...
The rings in your bore slowly spin around in their respective piston grooves all day long with the engine running.
They aren't in the same place that long anyhow.
So if money is tight and you are planning a rebuild sometime in the near future, it isn't that critical if you put them back in service with respect to each piston, as long as you run a little ball hone up and down the cylinder.... just a few strokes to give the rings chance to bite into something again.
You do not need to do a complete hone job to refit those pistons and rings.
*** What does matter is if the bore is out of round, the cylinders are out of spec in taper or a there is big ridge groove at the top...
and most importantly, if the rings have lost enough tension to not seal up anyhow.***

This is a common leakage area on the 550 mills. Re-tourquing the head cold, in sequence detailed in the service manual might help.

As above, if you are going to strip it then do a top end overhaul too whilst you are there. Oil leaks like this might not get any worse for some time if you want to leave it for a while.

That photo is really helpful. I'll bet my gasket/o-ring look identical. Any chance I can retorque just the outside bolts? What is the correct retorque procedure? Loosen all & retorque? Follow standard sequence loosen/torque in that pattern?

Tearing down the motor is not an option at this time, too many projects.

I am going to try come carb cleaner & wicking sealer. I will post results.

I just replaced all the gaskets in my 550 as well. Its unlikly it needs a retorque because there are only 3 bolts towards the center of the engine that holds the cylinders on. Its probably the o ring on the side of the block. The o ring is removed in this picture but you can see where it went around the oil jet things next to the #1 and #4 piston

SweetGPz wrote: That photo is really helpful. I'll bet my gasket/o-ring look identical. Any chance I can retorque just the outside bolts? What is the correct retorque procedure? Loosen all & retorque? Follow standard sequence loosen/torque in that pattern?

Tearing down the motor is not an option at this time, too many projects.

I am going to try come carb cleaner & wicking sealer. I will post results.

You can try a re-torque. It won't cost anything and may buy you some time. Tighten the small 6mm (10mm wrench) bolts in the center first. Then, starting in the center and working your way out, loosen each nut, one at a time, a 1/4 turn to break any resistance/corrosion and then torque to spec. You torque two of the center head nuts first and then go to the opposite side and torque the next two center nuts and work your way back and forth, two nuts at a time to the outside, if that makes sense.

missionkz wrote: Truthfully, this is generally a misunderstood thing and It really doesn't matter too much if you reuse the rings for a while...
The rings in your bore slowly spin around in their respective piston grooves all day long with the engine running.
They aren't in the same place that long anyhow.
So if money is tight and you are planning a rebuild sometime in the near future, it isn't that critical if you put them back in service with respect to each piston, as long as you run a little ball hone up and down the cylinder.... just a few strokes to give the rings chance to bite into something again.
You do not need to do a complete hone job to refit those pistons and rings.
*** What does matter is if the bore is out of round, the cylinders are out of spec in taper or a there is big ridge groove at the top...
and most importantly, if the rings have lost enough tension to not seal up anyhow.***

Sorry, have to disagree, rings in a 4 stroke do NOT rotate, they stay where you install them. I have pulled race engines apart over and over and the rings are in the exact same place. I always install the top ring gap on the thrust side of the bore, then the others 120 degrees from that. No matter how many miles after, they come apart in the same place.

It's OK to disagree... there are quite a few people on your side.
However, it has been proven time and time again, they move all over the place. Some say, especially with a fresh hone job on street vehicles,.
Extreme low time race engines....? Got me on that.
It's the reason you always pin a 2-stroke motor's rings.... can't let them them eventually spin and fall into the cylinder ports.

No, a 2 stroke's rings are pinned so they get installed in the right place, how else would you get the gaps exactly in the right place? Would LOVE to see your proof of rings spinning in the bores, a link maybe or something more than just rumours?