1981 Kawasaki KZ750 Resurrection

[rustybronco]

Found a reasonably priced powder coater a couple years ago, but leaning toward painting myself. Guess I should call this guy and get a firm quote. I have a blast cabinet, but doing the frame is the challenge.

I know you have already thought about it, but in your situation, you may be better off shooting the small parts yourself and let the powdercoater handle the frame.

[gmansyz]

Don't forget to lightly hone the cylinders before assembly.
G

[Nessism]

Don't forget to lightly hone the cylinders before assembly.
G

Hone even if reusing the rings? Rings should already be seated right? Maybe I'll start a new thread in the Engine forum for more feedback...

[gmansyz]

Yes. As it has now been disturbed and it may be out of round as well. Use a Precision hone not a ball one. You are doing a very light hone. Unless it is out of round, so go gently. Use the old rings unless there is oil burnt on the pistons.
Laters
G

[Nessism]

Pistons look good, but cylinders look a little funny. Going to borrow a bore gauge from work and measure them. There couldn't have been much blow by based on the pistons so leaning toward a light hone and reusing the rings. Stink'n rings are $45/hole (cheapest I've found). Would love to replace them but not at that cost unless it's absolutely necessary.

P1010332 by nessism, on Flickr

P1010335 by nessism, on Flickr

[rustybronco]

Deglaze the cylinders and reuse the old rings. Choice of stone will depend on the rings material. (240 to 320 if I read correctly)

[Nessism]

Deglaze the cylinders and reuse the old rings. Choice of stone will depend on the rings material. (240 to 320 if I read correctly)

Hey Dale,

I'm thinking 320 since don't need a rough texture to seat the rings per say.

Next question is whether the rings should be removed from the pistons? Seems like it takes quite a bit of flexing to remove rings so worried they may get damaged. Not worried about carbon in the ring lands, engine only has 10k miles on it.

[rustybronco]

Hey Dale,

I'm thinking 320 since don't need a rough texture to seat the rings per say.

Next question is whether the rings should be removed from the pistons? Seems like it takes quite a bit of flexing to remove rings so worried they may get damaged. Not worried about carbon in the ring lands, engine only has 10k miles on it.

If it were me doing the work and the piston can be easily removed from the connecting rods, I would remove the piston and ring assemblies in order to remove the carbon/varnish above the 1st ring land by using a combination of spray or dip type cleaner to remove the varnish, and a rotating wire brush to remove the carbon from the tops of the pistons. leave the rings in place if you think it best not to disturb them. Just scrub them well with hot soapy water after you're finished

I'm just not happy with the way upwards of the ring lands look.

[jwhelan65]

Hey Joe, I want to swap over to the black rectangular Gpz turn signals. If you have a clean set please let me know.

Unfortunately those were all destroyed when bike was wrecked. If you need anything else let me know.

[koolaid_kid]

I would hesitate to remove any of the rings except for the top one. If you break one it will cost you $45. Think of the cost vs. benefit.

[gmansyz]

Okay, my opinion.
If you can, remove the pistons from the rods. This will help ease the cleaning of the cases and such. I would NOT remove the rings from the pistons. Leave them on. Lightly sand the scuff marks on the piston's skirts. 320 is okay. Just to remove the high spots and smooth it out. The varnish above the top ring and other places is just fine. You can get at it with a wire brush, hand held, to remove the easy to remove carbon on top. And close to the ring land as you don't want it escaping when you reassemble the engine. It does NOT need to sparkle clean. When it runs, it will put more carbon back. Now for the cylinders, Funny wear pattern for sure. So, no ball hone. You need a precision hone to make it truly round again. I would try for 400 maybe 600 as the rings were already broken in once. And don't be afraid to run it hard after 25 miles. It will need it. Everything has already been heat cycled. You want to leave the rings on but can clean them ring and piston assembly in gasoline so you do not want to risk breaking any rings. Or tweaking them.
Have you though about porting the head? Maybe a factory ported GPZ750 head with Mikuni carbs instead of the off branded ones?
Laters
Greg

[Nessism]

Tore down the carbs tonight. 34mm Keihin's, which are a fair bit different than the GS Mikuni's. The pilot screws have a very fine and delicate tip, as does the slide needle. Float valve seat doesn't come out and float valve is rubber coated for a positive seal. Choke is totally different - a real choke with butterfly and everything. A whole bunch of linkages to make it work. Sort of a pain to try to remember where things go so I'm going to dunk the carb with the linkages attached. Will post up some photos soon...

[almarconi]

Choke is totally different - a real choke with butterfly and everything. A whole bunch of linkages to make it work.

Just take your time with it. The linkage on mine was pretty buggered up when I got the bike. It's pretty easy to bend it but once its all straight and adjusted it works pretty well. Z1 sells jets for the carbs if you need them, there are 3 in there primary main, secondary main and pilot jets. My bike has a V&H 4-1 and the it was pretty easy to jet the carbs for the exhaust. I left the linkages attached when I soaked the carb bodies. Used a rubber safe biodegradable cleaner so I didn't have to worry about damaging any of the rubber parts.

[Nessism]

Did a little blasting today...

P1010391 by nessism, on Flickr

P1010394 by nessism, on Flickr

[Nessism]

Ordering up parts, paint, and various supplies to keep this project moving forward. Member of the year Rustybronco (Dale) helped me select some suitable chassis paint and primer, which is inbound as I type.

Finding a decent stock master cylinder has proved difficult, since everything on ebay looks hammered. Found a late model EX650 master for $35 shipped so grabbed that instead. Thinking I might upgrade the hand controls too, since my current units are heavily weathered. The RH side should be easy enough; there are only three wires to deal with (kill switch, starter, and ground). The LH side is going to require more study.