1981 Kawasaki GPz550: Restoration

[Big T]

Are you going to file the pain off the fin edges for sock appearance?

[roeme]

The problem with threads that document such a nice and thorough resto is that it sets the bar so much higher for oneself.

I enjoy following this resto immensely.

[srsupertrap]

Last weekend I swapped the H/D valve springs from the 81 cylinder head, black into the 83 cylinder head on the left




Then masked the cylinder, head etc.


I used less VHT SP-139 this time around, hard to get deep in the fins but its colored

Back in the oven @ 210F for 65 minutes

[srsupertrap]

Although it appeared I lost interest in the GPz550 project, that was not the case. I relearned finding a skilled machine shop that can rebuild a cylinder head & bore cylinders and then turn the parts around in a timely manner is a challenge. From left to right Here is the new top end line up 1. Wiseco K615 BB kit 2. 1983 Kz550 cylinder bored to marked pistons 3. Cylinder Head: Head rebuilt, new bronze valve guides, new stem seals & bead blasted.

Here are my consumer comments, none of which reflect on the machining precision or tolerance of the following work. They do reflect how I was treated.


Suppliers
1. Cylinder Boring: Carolina Cycle Salisbury, NC 5/5 Stars

• Work performed: 83 KZ550 Deck/Bore/Honed cylinder
• Delivery 2.5 week turnaround
• Rapidray told me about this shop, no regrets

2. Cylinder Head Service: EBay smw70ss 2.5/5 Stars

• Work performed: 83 KZ550 Cylinder Head rebuild service, Install bronze valve guides, valve stem seals, bead blast
• Delivery 10 weeks turnaround.
  • I added bronze valve guides to the order when I learned how delayed the order was.
  
  
• I used this service to surface grind my GS1000 brake discs in 2007 . . . very happy.
• Very skilled machinist but 10 weeks is well . . . summer.

3. Cylinder Boring: APE Rosamand, CA 3/5 Stars

• Work Performed: 82 KZ550 Deck/Bore/Honed cylinder
• Industry leader
• Delivery 8 weeks turnaround
• I checked on my order after 5 weeks, got the Salesman pitch

The delays I experienced were due to me ordering in May. If you have a pending project I would send them out in the Fall.

Hope this helps others.

PS: Looking for a 1981 Kawasaki GPz550 Exhaust Camshaft or KZ550 Exhaust Camshaft w tach drive & 2 grooves (Performance Grind)

[srsupertrap]

Ed,
It won't be an issue. The 3rd & 4th photos are actually the plastigauge results for KZ550 connecting rod #3 & 4. Nothing has changed on the connecting rods but the plastigauge results are similar width to the plastigauge results for KZ550 crankshaft journals shown in the 1st & 2nd photo. The KZ550 connecting rods were running at that tight clearance.

Second both the GPz550 & Kz550 crankcases have no marks which indicates the crankshaft bearing insert OD's are the same. The GPz550 had "green" crank inserts while the KZ550 had "black" crank inserts which doesn't mean anything till looking in the FSM. Green is thicker than black or at least they start off that way from the factory.

FSM Crankshaft Bearing Insert
Model	Color Code	Thickness (New)
	Brown	1.991 ~ 1.995 mm
KZ550	Black	1.995 ~ 1.999 mm
GPz550	Green	1.999 ~ 2.003 mm

I actually numbered & measured all the KZ550 & GPz550 crankshaft bearing inserts before doing anything. Both sets showed some wear but the KZ550 black ones were approximately .01mm > than the GPz green ones. The results I got here were similar to the 2014 GPz550 plastigauge measurements (Thanks PB!). When I bolt the GPz crankcase together everything will have assembly lube. I will check the crankshaft rotation, at that time before getting too far.

Will the bearing inserts wear? Probably but the crankshaft journals are hardened and the bearing inserts are meant to wear. Will it sieze? If I saw line-to-line clearance I would switch to Brown bearing inserts.

[Nessism]

Steve, I fear the crank clearance is flirting with the minimum. You need at least .0008". Be careful.

[srsupertrap]

Although I suspected I could install the 83 KZ550 crankshaft and connecting rods in the 81GPz550, I had to measure everything to verify. While disassembling the KZ550 engine, some sand sprinkled on the KZ550 crankshaft while removing the cylinder. Good idea to disassemble, clean & grease Per the FSM the crankshaft and connecting rod insert/journal service limit is .10mm.

Crankshaft: Big squish > .051mm across every journal
[IMG][/IMG]
[IMG][/IMG]
Connecting Rod journal
[IMG][/IMG]

[IMG][/IMG]
Assembly lubed & good to install . ..
[IMG][/IMG]

[srsupertrap]

Switched to Imgur to show my plastigauge results from this last weekend. Before doing that following table is from the FSM

8/10/2017	1981 GPz550	GPz Notes	1983 KZ550	KZ Notes
Crankshaft Journal Mark	No Mark		1	Marked on crank, Points Side in 2x places
Connecting Rod Journal Mark	No Mark		O	Marked on crank, Pts Side in 1x place
Crankcase Mark	No Mark		No Mark	FSM: Pg 178 Lower Crankcase

Here's is the crankshaft bearing insert table; the GPz550 had green shells installed which indicated it was rebuilt. The KZ550 had black shells installed

Crankshaft Bearing Insert Chart
Crankcase Marking	O	No Mark
Crankshaft Marking
1	Brown P/N 13034-1016	Black P/N 13034-1017
No Mark	Black P/N 13034-1017	Green P/N 13034-1018

Sorry about your photos. I personally use Imgur and have never had so much as a hiccup.

[srsupertrap]

Looks like Photobucket is selectively playing hardball and ransoming third party hosting. I clicked on the following link Worth A Look to understand the recent change. I copied the following

Here is the answer they gave me. Unless you give them money, they will not unlock your links. Also, I don’t think the first of the 3 plans will work. I think they require you to use the most expensive one which is $400 a year . . . You can remove this bandwidth cap by subscribing to a Plus 500 subscription. Plus 500 users get 500 GB of storage, unlimited linking, and unlimited 3rd party hosting benefits.

Personally I was at 53%. This symptom will likely spread to others GSer's because when I clicked on user's photos most of them were hosted by PB. Great job PB!!!

[srsupertrap]

Morning Steve. Terrible luck with the motor, but it looks like you've hit paydirt with the donor bike. Might look tatty, but take what you need and hide it in a corner. I can guarantee you'll need to re-visit!

Maurice,
Good advice. The KZ550 donor bike parts sales on EBay has funded this portion of the rebuild. Ebay gets you coming and going though.

For others:
My GPz550 project is on hold for machining, APE has a one month turn around on cylinder boring. Business must be booming because they received the cylinder back on May 17th. No replies from them. The KZ550 head with 6300 miles is getting the following service, Ports and chambers bead blasted. 3 angle valve seat machining in Serdi equipment. Valve faces and tips ground and stems polished. All valve seats vacuum tested to ensure a good seal. Final assembly with new viton valve seals. Plus bronze valve guides. I don't anticipate having parts back till late June.

I have been discussing cam selection with Corey on the side. I have decided to sell the Moriwaki mystery cams on EBay. The Moriwaki cams have 8.25mm (.327") lift while the 1984-1986 ZX550 stock cams have 8.05mm (.317") lift. Not much difference and since I don't have the Moriwaki specs and centerline angle for the cams with 8.25mm lift, timing the cams becomes pretty time consuming. Below is Corey GPz cams, the MegaCycle race cams in the fore front. I will keep the degreed cam sprockets but Moriwaki stuff is pretty spendy. Wonder what I should put on the EBay BIN.


Changing subjects, we all know how rare 79-80 GS1000S mirrors are but I think there is one at least one item on the GPz550 that may be rarer yet. The fuel sending unit was only used on the 1981 GPz550 D1 and is unique to that model year. Although, the KZ550 used the same coffin tank it did not come with a fuel gauge. I have been refurbishing another GPz550 fuel sending unit which I cannibalized from a rough GPz550 parts bike heading to Steele's Cycle in Denver, CO. After disassembling the fuel sending unit, I got the wheatstone bridge to work again and it now gives the correct resistance values at the Hi & Low float. levels.



The connector housing is toast, I took a picture of the good one but the bad one has disintegrated from sitting in a field exposed to the weather. If you happen to have an extra connector like the shown please let me know.



That's the latest . . . safe riding

[MaurieG]

Morning Steve. Terrible luck with the motor, but it looks like you've hit paydirt with the donor bike. Might look tatty, but take what you need and hide it in a corner. I can guarantee you'll need to re-visit!

[Cipher]

eventually you'll want to put some Zephyr plastics on the bike.
HAHAHAHAHAHA

[Nessism]

Steve,
You should plastigauge the crank bearings after moving the bearing shells and crank over into your cases. I think the cases have bearing size codes stamped into the cases somewhere too so you may want to investigate that detail. Bottom line is that different cases take different size bearings so don't take anything for granted.

I'd use that new head. As you say, it's factory fresh and should clean up like new very easily. The fact that the carbs will fit up better is a bonus as well as you know. As for the valve springs, I'd compare the springs that came in your engine to try to figure out if they are HD type to match the cams or just stock.

Looks like you are doing a nice job. Keep going...

[srsupertrap]

Last week, I shipped a used KZ550 cylinder with a brand new Wiseco K615 BB kit to APE to have the cylinders bored. Corey, I finally followed your advice . I only later learned from Rapid Ray that Carolina Cycle does great work as well but with faster turns. Oh well.

After carefully numbering all the plain crank bearings, I have transferred the KZ550 crank bearing with 6300 miles to the GPz550 engine cases. It looks like the crankcase internals from the KZ550 are identical to the GPz550 too . . . so everything may be ported over.

I am struggling with what to do with the original GPz550 cylinder head which has had two valve jobs, the #1 NGK spark insulator breaking which required replacing both valves in cylinder #1 and the latest start up issue in March 2017 were the valves may have kissed piston #1 as the connecting rod let loose. Great history . . .



The easy solution is to use the 83 KZ550 cylinder head which is unmolested from the factory and still retains the original valve shims. This head could be easily freshened up with a valve job, port cleaning, new valve springs and valve stem seals and out last me. This 83 KZ550 came with CV carbs which also allows me to slip the Mikuni Flatslides TM27 directly into the stock boots, see below.



This solution is appealing because the carburetor adapters the PO had machined (81GPz550 & Many 80-83 KZ550 came equipped with TK22 Slides) are not spaced correctly. For example, most Suzuki GS carbs are spaced 77-93-77mm. When the carb spacing is incorrect the only thing to give is the carb boot. Installing the above carbs in the original GPz550 cylinder head is a feat of strength requiring heat gun prep and JB penetrating oil. Just more evidence the PO did his best.

My only reservation is the 83KZ550 cylinder head has a different casting and looks different than the 81 GPz550. The cylinder fins are not rounded but instead angled at 45 degrees. I know I would hear the comment its got the wrong cylinder head . . . thoughts?