1981 Kawasaki GPz550: Restoration

[srsupertrap]

I don't know whether the PO did the work but its a mess . . . and I will have to double check everything and scrub everything too. I got my order of McMaster Carr S/S M4 Hex Screws yesterday so I reassembled the carbs. 10X per Carb

You have to line up: fuel lines @ bottom, vacuum hose and those throttle shaft covers while inserting the throttle shaft

Apply medium to the set screws and this is where I ran into problems

 

[srsupertrap]

Looks good but when I ops check the choke slide it slides out but slides right back in like a greased pig (or other analogies). Hum they were working before. The I get it, that that must be that micro sized ball bearing I found during disassembly. I check the Sudco RS exploded view and discover I am also missing the spring which pushes the ball bearing against the choke shaft.

Well the Sudco site has the springs but I don't know if its the same size. Then I remember while vacuum cleaning the carpet below the work bench I heard something get ingested. Its worth a look inside. . . some one is looking out for me because I find the wayward spring (next to the Penny)

The spring and ball bearing go right in there by the penny. The spring resides in a hole & the ball bearing (shown) sits on top engaging a notch in the choke shaft. Put it back together and now it works. Lucky

Next Bench Synch & install Z-1 17mm drain O-rings. They are done, next set will be easier.

 

[steve murdoch]

Looks like i will have to start doing some housework again.
Lost the clip from a master cylinder the other day.
I have enjoyed following this resto.

 

[srsupertrap]

Steve, Glad you are enjoying the thread & its always worth a look. Finished the S/B carbs Friday: Bench synched them & installed the Z-1 float bowl O-rings

Some have wondered why I have not just pulled the head & jugs to have a looksee inside. Well if its a Moriwaki 593 big bore kit lurking inside I have been told those rings are no longer available . . . then the only rebuild option would be Wiseco 615 kit, bore, gaskets etc and that means substantial $$$.

Finally refitted the cams today after chasing M6 threads & repairing half of them with helicoils (Lousy Design: Penny wise . . . ). Cleaned everything, filled the oil galleries & applied assembly lube.

Set to TDC, Ex "mark" pointing to the correct pin . .

The intake Z/5 is lined up correctly. I respositioned both cam sprocket bolts in the middle. The smucklehead builder decided to loctitie those bolts with the Red-high strength

Installed the manual cam chain tensioner, screwed in the bolt to lightly contact the cam chain and turned the engine over by hand. This photo shows the timing index mark is pointing to "F" (With cams in the position shown above). It should be line up with the "T" just like a GS model. I will pull the Dyna ignition and look behind. Next I have to make a TDC tool out of one of the fouled spark plugs & then degree cams

Note: How far the ignition was advanced & the condition of the Philips head screws. That why I call him a smucklehead.

 

[Big T]

Your bike is a paradox of fine hardware and someone who put it together with zero care

Nice to see you're getting it all fixed

 

[nvr2old]

The carbs alone would've sent me away crying. Man, that's a lot of parts to get back together the right way. You're really doing a nice job on this bike. I'm sure it will be happy to be correct.

 

[srsupertrap]

This may get some discussion going. Didn't mention this earlier but while checking the valve lash I found a 2.05 valve shim residing in the #2 Exhaust. While reassemblying Sunday I found a 2.00 valve shim (smallest shim size available) in the #4 Exhaust. In fact all the intake & exhaust shims were on the thin side which I am guessing was attributable to a ream happy valve job.

Brings up a good question . . . when a valve recedes into head under normal use one reaches the point were the head has to be rebuilt or replaced. BTW, I don't know how you add material. What's the consensus in this situation were the machinist most likely removed way too much valve seat material on a head with 24K?

Note: GPz shims run from 2.80 down to 2.00mm minimum.

 

[Big T]

You can skim .5mm from the top of the valve stems, but you'd have to pull the head

 

[tkent02]

Maybe the guy advanced the timing to help tune for the high elevation? It does help sometimes.

Are heads for that engine dime a dozen like GS heads or are they special for the GPz and thus expensive?

 

[srsupertrap]

Jumping around a bit but bear with me. Over on the GPz550 Forum Garyinnj made the following comment which may explain why the crank timing marks TDC 1-4 don't line up perfectly with the cams which are installed correctly. . .

Originally posted by garyinnj "I've found the most common reason for marks not aligning perfectly is (normal) chain stretch/wear. Given your engine's hi performance mods I also wonder if the head was aggressively resurfaced which would also effect alignment."

So I took a picture and posted it here. Looking at Head Gasket looks like like there is less material on the Head side. Not measurable but what does yours look like?

 

[srsupertrap]

Maybe the guy advanced the timing to help tune for the high elevation? It does help sometimes.

Are heads for that engine dime a dozen like GS heads or are they special for the GPz and thus expensive?

Who knows what the guy was doing . . . No the GPz heads are different than KZ models and more rare.

You can skim .5mm from the top of the valve stems, but you'd have to pull the head

Big T, Thanks for the good advice . . . I never thought of that either. I wonder how much a Shop charges for that operation?

The carbs alone would've sent me away crying. Man, that's a lot of parts to get back together the right way. You're really doing a nice job on this bike. I'm sure it will be happy to be correct.

nvr2old, Thanks for the encouragement . . . I thought this was going to be an easy refresh were I could focus on the cosmetics.

 

[srsupertrap]

On Wednesday night I rechecked the valve lash. I adjusted five valves (4 Intakes & 1 Exhaust) and to my surprise I found no change on two of the intakes and another intake was still too tight (on two of those tight intakes I had reduced the shim size by two sizes i.e. 2.25 to 2.15) Confounding the issue I adjusted one loose exhaust valve by bumping the shim up by .05mm and that tightened up that exhaust valve lash into spec.

While you think about how that could happen. . . . I called Tom Klemme, Trippivot's friend the following day on Thursday. Tom did my 1100G head & porting and boring the 1100G cylinder for the 73.5mm Wiseco pistons. I told him it was mess, required lots of inspection, weld repair, skim valve stems etc etc

Friday night snowing in Colorado Springs again so I pulled the head

Looks rich no surprise there

Didn't remove the pistons yet, they are held in by spiral circlips which I believe is aftermarket only

Need help understanding how to get the front cam chain guide removed from the cam chain tunnel . . . . it has square peg (shown) on the top & bottom.

Cylinder walls look serviceable

Going to try to ship the head & cams on Saturday . . .

 

[srsupertrap]

Here is a couple of photos of the bottom of the head, see some interesting markings (between the studs) similar to the ones on the cams. I wonder if it's a Moriwaki head, I don't see Kawasaki embossed anywhere . . . running a bit rich

Then I see this marking . . . first time working on Kawi so I have no idea
. Might be similar to Ed's KZ750

Pic is blurry but check how close the intake valve is to the cylinder head surface

Pistons measure 60.75mm at the skirt

Off to Klemme Performance Motorsports, I cannot resurrect the patient by myself

 

[Guest]

So what are you having them do to the engine?

 

[Nessism]

Pistons show some blowby. You figured out if rings are available yet?

 

[srsupertrap]

So what are you having them do to the engine?

Well I asked Tom Klemme to first measure & determine the serviceability of the head i.e. does it even have a second chance or is it a "boat anchor". If ok then

- mask & bead blast the head
- check valves guides, replace as required
- freshen/redo valve job
- skim the valve stems, retainers etc & adjust back into range
- R&R valve stem seals
- weld repair the fractured piece
- repair buggered threads

I told Tom to call me once he evaluates so this is the short list.

Pistons show some blowby. You figured out if rings are available yet?

Corey Clough the administrator on the GPz550 , knower of GPz550s said Wiseco BB kits & rings are available for the 615 BB but not the Moriwaki 593 BB pistons. My measurements may be low but the math says this has a 615 BB. Z-1 probably can order them, if not Wiseco.

Ed, could you look under your cylinder head and see if you have those marking embossed in your KZ750?

 

[Nessism]

Ed, could you look under your cylinder head and see if you have those marking embossed in your KZ750?

Steve, my head has the same marks. I think the round ball thing has to do with date code/lot control, although I didn't study it.

Regarding the rings, those don't look like Moriwaki pistons so I think you are on the right track. Moriwaki typically used one compression ring, L shaped, so that's further evidence.

 

[Wester Cooley]

For replacement rings for pistons that were NLA in the past. I used to have good luck with Total Seal Ring Company on having rings that would fit the pistons I had. Used to give them the measurements of the rings and the piston diameter, and the ring grooves, and they would see what they could come up with.

I have not talked to them in like 10 years now, but its worth a shot. Moriwaki didn't make the rings themselves, they bought them from somebody somewhere.

 

[srsupertrap]

For replacement rings for pistons that were NLA in the past. I used to have good luck with Total Seal Ring Company on having rings that would fit the pistons I had. Used to give them the measurements of the rings and the piston diameter, and the ring grooves, and they would see what they could come up with.

I have not talked to them in like 10 years now, but its worth a shot. Moriwaki didn't make the rings themselves, they bought them from somebody somewhere.

I have determined its a Wiseco BB 615 kit so it's definitely worth a shot . . . thank you. I have already sent them an email. http://www.totalseal.com/ContactUs.aspx

Because Corey Clough informed me, yes Wiseco still makes a GPz550/615 Big Bore kit but Wiseco discontinued their old style GPz550 piston & rings . . . so my 1980's BB kit piston rings are NLA too. Probably not too wise to reuse those rings . . .

 

[srsupertrap]

Well I received some welcome news today from Total Seal Piston Rings, see below

"Steve,
Just need to verify bore size of the cylinder and the ring groove sizes on the piston. Once we have that we should be able to fix you up.


Best Regards
Keith Jones"

Not being a Machinist does Keith need the minimum bore size of all four cylinders? Reading Ed's KZ750 thread I do not have a Bore Gage at my disposal so what would the experienced Machinist suggest I do?
BTW if you were boring a new 615 Big Bore kit cylinder what is the correct formula: 615/4 plus ?