Project: 1990 ZR550 Zephyr (yes, another one)

slayer61 wrote:

Start with a clean .. really clean bike/engine and pay really close attention?

Agree!  Clean super well...they spray talc foot powder on the suspect areas.  Then start up the bike and watch close.

Thanks guys, I'll give that a shot.

Follow up to the previous question about some leaks I’ve got. 

I cleaned it up real good this morning and then started it up and let run for a bit. The leaks did not start up again, so I took it for a ride. By the time I got where I was going the leaks were back. As far as I can tell they’re coming from horizontal splits below the cylinder block, and crank case. Photos below. 

I’m guessing this means I’m looking at a full engine-out rebuild and replacement of those gaskets? PO probably used non-OEM gaskets when he rebuilt it. 

Perhaps it’s too hard to see in the photos above. Here’s some more photos, hopefully you guys can see it better. I’m worried that maybe the leaks are getting worse. Seems like the oil spots on the ground are getting bigger. 

 

it appears higher than the crankcase seam but lower than the head which would suggest "base gasket" or seals - have you taken the oil filler cap off when it is running to see if there is excessive crankcase pressure (blocked breather, worn rings etc)

No, I have not. I'm unfamiliar with the process, is that covered in the FSM?

Stereordinary wrote:

No, I have not. I'm unfamiliar with the process, is that covered in the FSM?

I don't know, probably not. You are in the enviable position of having a second identical bike to draw comparisons from. I am not saying you have excess pressure however it looks like you are going to have to replace the base gasket (once it's leaked for whatever reason it won't seal back up) anyway so it's worth checking first. It will at least help ensure the new gasket doesn't leak. Excess pressure is normally one of three things, overfilled oil level, piston blow-by or a restricted crankcase breather.
If you take the oil filler off when it's running and put your hand over it tightly you will feel a "pulsing" if it's piston blow by (compare with your other bike)
If you can reach it, disconnect the breather from the air box (with the oil filler refitted) and put your hand over it to feel the air flow coming out (again compare with the other bike, if the air flow out of the leaker is less than the good bike chances are the breather is partially blocked on the leaker)
Blocked breathers are normally a result of poor maintenance and infrequent oil changes.

Have you tried retorquing the head nuts? That’s worked wonders for me in the past with both head and base gasket leaks. It’s actually recommended as part of routine maintenance.

Thanks fellas. I'll try both of your suggestions when I can. Wookie's will be a little more difficult because my other bike is in my shop at the moment. 

Just took a photo to submit this bike to display at The 1 Moto Show in Portland in April next year. Wish me luck!

Looks fantastic, all the best. you have done a great job.

rob b