1981 Kawasaki GPz550: Restoration

[srsupertrap]

All bad news when I did a compression check on Friday, my setup

#1 cylinder is where the spark plug insulator failed

Rest were like this . . . 5300Ft

NGK forced my hand had to have a look inside, it gets worse

Looks like insulator residue, valves seemed to be straight but that needs to be verified

Not a catastrophic set of photos but its loosing 30+ psi somewhere.

Although I didn't buy the plugs, I contacted NGK and they sent me a claim form for the damage. They want the spark plug for a failure analysis investigation ( I am sure they will find a way to deflect the claim ). Regardless, I will submit a claim for a cylinder head, gaskets and piston but the Wiseco 615 piston in the photo are the XC type which were discontinued long time ago so there is no hope of finding one of those. I will probably have to replace all the wiseco pistons with new or find a new cylinder and run stock Kawi pistons.

Either way its a total mess & money pit too.

 

[Nessism]

Wow! Bummer!

Steve, some dings in the top of the piston won't hurt anything. Same goes for the head. Can't you just replace the valves that are damaged and kiss the seat with a cutter as necessary?

 

[DohcBikes]

If NGK denies anything but full compensation for the failure of their product and the resulting consequence I'd be very surprised. Itemize everything, they have a budget for this kind of thing.

On a side note, GPZ550 was the first bike I ever rode.

That seat is done for, unless going oversized.

 

[chuck hahn]

Looks like 1 valve is junked for sure.

 

[Fjbj40]

Machine the valve and seat, then measure. If it is within specs you are good to go. Piston damage looks negligible.

Damage on head can be blended easily.

Pictures are high quality, but diagnosing the parts as junk or serviceable cannot be done from them. Measure after they are cleaned up and then go from there.

Personally I would step back, throw a cover ver the bike and parts and cool off for a few days, your emotions will feel better for it. Then get the machining done and go from there. Sometimes we get too caught up in things and a little break goes a long way, it works for me anyways.

Cheers brother and persevere.

 

[Guest]

Well, that stinks! Looks repairable for sure, but it sure isn't what you had in mind. How does the cylinder wall look? Hope it's still good. Ray

 

[srsupertrap]

I shipped my NGK claim off today. I included several 8?10 color glossy photographs, just like Arlo's Guthrie's Alice's Resturant song along with the Kleeme Performance bill for the cylinder head work done in 2014. That's outa of my hands and I now I wait.

Now I need a machinist who is interested in helping to look at the cylinder head, valves etc. Then pass judgement ( rework or boat anchor ). Although I agree it does not look terrible, I am worried about the following. Although the GPz valve shims are smaller in diameter than the GS's, the range of sizes are the same 2.00 to 2.95mm. The 2014 valve job reduced the shim size down to 2.25mm on the intake which leaves little valve seat material to remove. I am no machinist but there is not much material left.

I also believe something bent. When Ray was in my garage a couple of weekends ago, the top engine sounded like something was rattling around loose in there. When disassembled I found no big pieces of insulator left inside which would account for the noise. Could the connecting rod bend?

I contacted Kleeme Performance but no reply. Open to suggestions

 

[Nessism]

Steve, your machinist guy should have kissed the valve stems to shorten the valves. That moves the shims back into the normal range. If you think the valves are bent put them in a V-block and give them a spin. You can try chucking them up in your drill motor too.

 

[Guest]

Steve, I bet all the noise came from that piece of ceramic. It's likely that the crank and rod are fine, just my opinion. If the piston and head can be cleaned up and the cylinder wall is ok, I expect the valve work to be minimal. Should be running in no time. Ray

 

[Nessism]

Any update Steve? Have you done a full damage assessment yet?

 

[speedfreeq]

Hey y'all! I'm new to the site, not a GS owner, but a moto guy nonetheless. I'm about to pick up a 1982 GPz550 much like yours, Steve! Been sitting for a loong time, but all the pieces are there and the bike's only showing 21k.

My plan is to take it vintage racing. Way back in 1987, I had an 84 GPz. I learned to ride (like, really ride) on that bike! I was eighteen and stationed on a submarine out of Norfolk VA. My love of all things two-wheeled goes back to that bike. I can't wait to put the old thing on the track and have some fun mixing it up with guys my age

I'm a machinist, BTW - floor foreman at a big job shop here in Asheville, NC. If anybody has more resources for race-prepping a 30-odd year-old bike, please point me in the right directions. I'm elbows-deep in that Google search now

Cheers!
Fred Schuldt

 

[srsupertrap]

Hi Fred,

Welcome to the GS Resource Forum. You will find the forum is a great place to learn, discuss your & others projects and find solutions. Many members love all the memorable UJMs so this would a good place to start a thread or the GPz550 Forum. Lots of the GPz550s H models were raced but they still come up for sale in complete street trim for about $2 to 2.5K on C/L so you might want to think twice about restoring something sitting for decades. That's my bias now.

I also have been trouble finding a competent machine shop that can perform a basic three angle valve job, blend ports and also values my business i.e. responsive too. I sent this head before it blew up to a shop in Iowa in 2013 that wouldn't even return my call . . . nice. So I contacted a local machine shop who milled my GS1100G cylinders back in 2012. When we examined the cylinder #1 head surface we found material fused to the cylinder head and also the head gasket. After sitting for two weeks the verdict is to replace both the intake & exhaust valve. I ordered a NOS intake and exhaust valve from EBay which are due later this week. Surprised to learn the GPz550 valves are the same size as the KZ550 valves. I asked the machinist, who specializes in English bikes to also grind the valve tips from the other three cylinders to get the shim size back in the upper end of the 2.00 to 2.95mm range. I made the same request to the shop in Iowa

I received a reply from NGK USA, they stated they didn't find any problem with the returned D8EA spark plug. The spark plug has been shipped to Japan for failure analysis and a response is due within 6 months. I am still betting they find some means to blame me. I have ordered all new gaskets especially after examining that head gasket.

That's the latest news on GPz550 S/N 000030

Steve

Hey y'all! I'm new to the site, not a GS owner, but a moto guy nonetheless. I'm about to pick up a 1982 GPz550 much like yours, Steve! Been sitting for a loong time, but all the pieces are there and the bike's only showing 21k.

My plan is to take it vintage racing. Way back in 1987, I had an 84 GPz. I learned to ride (like, really ride) on that bike! I was eighteen and stationed on a submarine out of Norfolk VA. My love of all things two-wheeled goes back to that bike. I can't wait to put the old thing on the track and have some fun mixing it up with guys my age

I'm a machinist, BTW - floor foreman at a big job shop here in Asheville, NC. If anybody has more resources for race-prepping a 30-odd year-old bike, please point me in the right directions. I'm elbows-deep in that Google search now

Cheers!
Fred Schuldt

 

[Nessism]

Surprised to learn the GPz550 valves are the same size as the KZ550 valves. I asked the machinist, who specializes in English bikes to also grind the valve tips from the other three cylinders to get the shim size back in the upper end of the 2.00 to 2.95mm range. I made the same request to the shop in Iowa

That's the latest news on GPz550 S/N 000030

Steve

Steve,

You gotta be careful how much is removed off the valve stem because you may wind up with a situation where the valve keepers are sticking up above the valve stem. If that's the case you can shave the keepers some. At any rate, be careful in that regard.

Oh, and glad to hear you are moving forward.

 

[srsupertrap]

The cylinder head is now repaired with two new OEM valves lapped in #1. The machinist who repaired it was also to busy with large commercial machining jobs from local companies like Coorstek, Golden, CO. So I removed all eight valves and had SCH Racing Heads in Arvada grind all the valve stems down with a target valve shim size of 2.8mm. Since the majority of the valve shims were on the low side in the range of 2.10 to 2.30mm, I asked SCH to remove .50 (.020") to .70mm respectively from each valve stem. It took him a half hour while I waited.

If by any chance anyone has an extra Kawasaki 13mm shims from other projects in the range of 2.75, 2.80 & 2.85mm please let me know because I am ready to bench shim the head and have shims to swap too. Thanks

PS: Ed, didn't mention but the valve keepers are no where near the valve stem tips.

Later found Hot Cams offers 13mm valve shim 5 packs
https://www.denniskirk.com/hot-cams/13mm-valve-shim-kit-2-80mm-5pk1300280.p146577.prd/146577.sku

 

[Nessism]

So watch the keepers now Steve and make sure they don't stick up above the top of the valve stem. If they do you will have to shave the keepers.

 

[srsupertrap]

Bench shimmed the GPz head this weekend with a Hot Cams 13mm valve shim kit. The valves are all set to the loose side. Pretty happy with the results now that all the valve shims are back in the middle of the range from 2.00 to 3.00mm. Took longer than I expected but what else is new. Accel spark plugs this time around.

PS: SVSooke when the time comes if you need 13mm shims let me know.

 

[Nessism]

Be sure to double check your valve clearances after the head is installed. They sometimes change after the head is installed and torqued down (learned by experience).

 

[SVSooke]

Bench shimmed the GPz head this weekend with a Hot Cams 13mm valve shim kit. The valves are all set to the loose side. Pretty happy with the results now that all the valve shims are back in the middle of the range from 2.00 to 3.00mm. Took longer than I expected but what else is new. Accel spark plugs this time around.

PS: SVSooke when the time comes if you need 13mm shims let me know.

LOL you knew I'd be watching this thread,if I need them I'll be PMing you first:encouragement:

 

[Guest]

Allrighty then! That's good to see, Steve.

 

[Nessism]

The cylinder head is now repaired with two new OEM valves lapped in #1. The machinist who repaired it was also to busy with large commercial machining jobs from local companies like Coorstek, Golden, CO. So I removed all eight valves and had SCH Racing Heads in Arvada grind all the valve stems down with a target valve shim size of 2.8mm. Since the majority of the valve shims were on the low side in the range of 2.10 to 2.30mm, I asked SCH to remove .50 (.020") to .70mm respectively from each valve stem. It took him a half hour while I waited.

If by any chance anyone has an extra Kawasaki 13mm shims from other projects in the range of 2.75, 2.80 & 2.85mm please let me know because I am ready to bench shim the head and have shims to swap too. Thanks

PS: Ed, didn't mention but the valve keepers are no where near the valve stem tips.

Later found Hot Cams offers 13mm valve shim 5 packs
https://www.denniskirk.com/hot-cams/13mm-valve-shim-kit-2-80mm-5pk1300280.p146577.prd/146577.sku

Good news about the keepers Steve. And those shims from Dennis Kirk are a great find. Most places charge that much for one shim vs. a pack of 5. I may have to order me a few just in case.

One last comment, on my KZ750 the valves clattered quite a bit with the clearance set at the high end of the spec. The noise bugged me so I went back in and shimmed the valves down toward the low end of the range. I've still got one valve that's clattering but I'm too lazy to go back in. Adjusting the valves when you have to pull the cams is quite a bit more work than the GS shim above bucket type.