She's Dead for now

Unfortunately my poor baby KZ550 is out of commission. Misfire on #4, had spark and fuel. Compression was low 30's, sprayed some soapy water around the head gasket and voila it had a blown gasket. No biggie, but i decided to test the rest of the cylinders... glad i did. the other three had a compression of 39-45 psi... put a little oil in there, compression went up. She's got bag rings. After all that work, now the engine needs an overhaul! can't do it now, no garage to use. but i will in the future and i would love some advice or tips if you guys have any! best brand of parts, where to by them, things to look out for, anything will help.

Side note, thinking about making her into a Steampunk ride with a bit of rat rod style. Thoughts?

Have you adjusted the valves yet? The clearance reduces with mileage and many people don't do maintenance so eventually all the clearance goes away and then the bike won't start because of low compression.

Also make sure your compression tester has a valve in the tip. The ones that don't can mess with the readings on smaller displacement engines.

M_a_t_t wrote: Also make sure your compression tester has a valve in the tip. The ones that don't can mess with the readings on smaller displacement engines.

Yes. Need to check that before removing any motor parts.

30 to 45 psi on all cylinders would have meant the bike would not run at all.

The bubbling cylinder does mean something is happening, but maybe it's not as bad as a full ring set and hone etc.
If you do a proper compression test and you only get 150 psi or so, then you might want to do a cylinder refresh with rings. A good motor with proper compression tester and proper procedure will be close to 180 psi on Kz550 motors.

When you added oil to the cylinder did go up above 100 or 150 psi. If not, look for a new tester or make sure you did the test correctly. And of course, as Nessism said, look into the valve adjustments. But read the valve train warning in my signature bfore opening the valve cover.

Calvin9819 wrote: ................. put a little oil in there, compression went up.....................

Adding even a little oil will always makes the compression go up even in a brand new perfect engine. The diagrams below explain. Ed

Valves were adjusted last season when I bought the bike to be sure there’s no issue with that. Either way, the head will need to come off for the head gasket and lll be doing some quick measurements to see how bad the cylinder walls are. I’ll be looking into all your guys’s Advice as well because there’s definitely some stuff brought up that I missed. But either way, I got myself a 2006 VN750 and I’ll be using this kz550 for a custom bike as long as the engine checks out and can be successfully rebuilt. I’ll post pics of every step when I get started! Hint, I’m going for a Steampunk design.