An odd Rattle...

If those are still available, you also need rings. The Kawasaki Pistons are not sold with rings, they are additional. Yes the Oversize is like that +.020" might be first oversize or they may have had a .010" as the first offered. If you clean the crown of your pistons, they will show either STD which is standard bore. Or you might fins an oversize already, you could also measure the bore, to see the size.

They also had the ring sets listed, unfortunately bike bandit is notorious for listing parts they don't have, so finding them there just means I know what I'm looking for. It's starting to look more like the tools are going to cost more than the parts. Proper spring compressor alone costs more than both new pistons and rings combined! Add in lapping tool, honer, reamer... Might as well buy a new engine just for the cost of the valve tools!

Not worth it to try and buy the tools for Proper Valve work, they are very expensive. The head would be taken to a machine shop, with the Cylinders/ Pistons etc. Definitely not cheap. A good used engine, or maybe a parts bike might be found? Sometimes they just fall in your Lap. Maybe someone here has a motor?

Ideas for a diy valve spring compressor tool.







When re-assembling the pistons (with rings) into the cylinders, chop-sticks or pop-sickle sticks may prove useful.

Good Fortune!

A friend of mine mentioned maybe doing a sleeve in the cylinder instead of trying to find larger pistons. What is the feasibility of this? At this point I'm going to start by getting replacement rings and gaskets then retesting compression. Maybe getting valves done. I can't have my means of transport out of commission for so long, so it's band-aid time. I wish it wasn't this way and that I could spend all the time in the world making this little KZ the best damn 30+ year old 400cc bike... but it has got to wait. Gotta get to work first.

Have been able to measure up the cylinder? In the 4 cyl engines a sleeve can be changed out quite easily. They are a interference fit. I've done several by placing upside down in the Oven, Make sure the Kitchen has no Women around, upside down on a steel can, a coffee can will work. About 400-450, and wait for the clunk, that means sleeve's out. Now while hot the replacement sleeve will drop right in, but it will draw the heat quickly and then Stick in place. If it has not seated correctly, or in a Two Stroke Motor with ports not aligned, just repeat the process. Welding gloves as a "Hot Pad" work great. Bore must be measured after install, and very well could need Honing, or maybe boring depending on the sleeve dimension.
Did you measure the piston skirt to cylinder wall clearance on the scored one? Is this the Rattle? Loose piston?

With no time or money to replace parts or have valves actually inspected, I've pieced the engine back together to do a little test. Now I'm fairly certain that the compression problem is in the valves. I know I keep bouncing all around, but eventually it will get resolved! Anyways. I should have done this earlier. After reassembling the engine, I placed my hand over the intake boot and pressed on the kick. I felt suction, good, then pressure blowing back on my hand, probably not good. I tried this with the "good" side, and only felt suction. I did the same with the exhaust. Felt pressure and suction on both sides. Now I just need to take the head to a shop and have them work on it. Also replace every damn gasket on the motor, and probably do the rings just for fun.

You will get some blow back thru the intake when turning over the motor slowly, as both valves are open momentarily on the exhaust to intake suction stroke. There may be blow back or not depending on exact rpm this is done at - NOT a reliable test for valves so forget it.

Maybe you should get a good manual and learn up some. Proper diagnostic techniques will save you lots of $$$ in the long run.

Compression guage/leakdown tester and some oil... not expensive. Save $$$ and time.

Good luck.

Getting the head back tomorrow, going to put it all back together and go for compression test again. If I replace the rings, do I need to de-glaze the cylinder?

Robwolf wrote: Getting the head back tomorrow, going to put it all back together and go for compression test again. If I replace the rings, do I need to de-glaze the cylinder?

Yes.

For a recent thread with some helpful info,
click > www.kzrider.com/forum/2-engine/491122-re...ams-do-i-need#491122

Good Fortune!

I was scouring the web looking for the proper pistons and rings if I needed to go OS and haven't had the best of luck. From what I've read on the Kawasaki site and Powersports Plus, the H1s pistons are already 1.0mm (0.040) OS. Apparently the '78 C1 used the 0.5mm (part 13029-1006) and the '79 H1(my bike) uses the 1.0mm (13027-1008). Even weirder though Kawasaki lists part 13025-5010 a 0.020" set of rings on that 0.040 piston... *brain overloads* I'll have to clean the top off mine and take a look, but this could be bad news? Could the rings that are indeed oversized from earlier models fit on the later models "stock" oversized piston. Example, get the 1.0 ring for the '77? Are the rings thicknesses different though? Would it actually fit the piston?

Still chasing demons... had a quick q though. Wouldn't bad rings show themselves with oil smoke in my EX?