1981 Kawasaki GPz550: Restoration

[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/...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

[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/...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.

[srsupertrap]

I am with you Ed adjusting shims on KZ's is time consuming and makes one a expert Helicoil repairer. I bought the entire Hot Cams Valve Shim 13mm kit on Fleabay for $56 shipped. I am currently low on 2.70 shims though.

I received a Fed Ex box on Tuesday from NGK, response below.

.

[alke46]

The very response you thought was coming, right? Not what you wanted but they always seem to have ways to deny claims.

[srsupertrap]

Certainly seems that way. I moved the GPz550 to the indoor shop for the winter. Stocked with all new OEM gaskets I will reassembly this weekend

[GS1150Pilot]

Looking great!

I absolutely love those bikes.

[Fjbj40]

In its journey from the factory to your hands it may have been dropped.

Not saying it was you, it did however hit the floor or something.

General rule, if a plug hits the floor, you pick it up and throw it in the garbage.

I hate it when the parts guy dumps the plugs you just asked for on the counter, I say " go get me 4 more please". When he hands them to me I say "now you can do whatever you want with the first 4"!