1981 Kawasaki GPz550: Restoration

[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]

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?

[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?

[Big T]

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

[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.

[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.

[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

[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.

[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]

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.

[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

[Nessism]

No wonder the PO sold the bike so cheap. He knew where the skeletons lay and had a conscious.

[srsupertrap]

Both of the #5 Cam Bearing Cap bolts (Intake #1) were stripped & bear to remove. Tried running my M6 tap down one hole and it stopped. Not wanting to relive the joy of removing a broken tap I decided to have a look inside. It had been repaired already with a helicoil. I fished out the helicoil with a dental pick & Vice Grips


Same thing on the rear one. I then realized these smuckleheads repaired the threads with the wrong helicoil size . . . probably 1/4-20



They installed the dowel pins in the wrong orientation too, bevel side should be up. What else did they do wrong?



The helicoil drill size 1/4 fit perfectly in the cam bearing cap hole so I use it to guide the drill. I mark the drill depth with a Sharpie as shown.



A quick ream on both sides



Then helicoil tap both bolt holes



Don't use Helicoils often but sure beats removing the Cylinder Head. I run the inserts down, reinstall the cam bearing cap run the a couple of good M6 bolts down and ops check GOOD!

The epoxy is intended only as a type of glue, not to replace an actual metal part.

[srsupertrap]

I'll bet JB Weld or Liquid steel would work great for that repair. Clean it well where the pieces meet and apply the JB to both parts before attaching. Maybe run the tap through one more time after it dries.

Rather than JB Weld I suggest an aluminum-based epoxy, such as Hypoxy Alumfast.

Cool, the Hypoxy Alumfast stuff is available on Amazon.com. That little sheared off piece does not fit like a glove or snap into place. Think its best to just fill the area with epoxy, shape it and paint or try to refit the sheared piece?

Thanks for the help.