1981 Kawasaki GPz550: Restoration

[srsupertrap]

Wheeled my GPz550 into the garage today to begin the restoration/rebuild. It's been stored inside for 27 years and I would like to be done by June 2014. Yesterday by searching the net I discovered this GPz 550 is really a race bike (8rt Exagerration). The PO installed a 615 cc big bore kit, race cams, 26mm Flatslides, Yosh exhaust, Dyna Ignition with 2.2 grey coils and also stated the engine was balanced & blue printed. Today was tear down

First the seat goes, I will need new hinge pin and better yet an original 1981 seat.

Next the Flatslides go BUT they are stuck so I use the hairdryer

The slides are stuck so getting the throttle cables out was a PIA but they came off & will need a new cable because it frayed

I get the Flatslides off and look down the intake ports . . . looks shiney. I also notice the cam chain tensioner is not an automatic spring loaded factory jobbie.

Pipe is next to go, whoever installed it tightened the little 10mm nuts to the point where they bent the exhaust flanges. The outer exhaust stud is stripped that needs to be replaced too

The only marking I see on the "Yosh" pipe is KZ 51, KZ 52 etc on the header pipes. No Yoshimura marking?

Looks like a Yosh or RB Racing pipe. Have not tried to take it apart yet.

2/11/18: I contacted RB Racing & sent a photo in 2017 and received a reply the exhaust was not a RB Racing. Like Big T stated it's a Yosh

Next I install the centerstand I purchased from Joe (Jwhelan65) so I can work on this bugger

Two and half hours later I have reached a good stopping point. I need a rear fender if anyone spots one 80-84 KZ550 will work

I also want to welcome my friends from the GPz 550 Forum following this thread. I cannot post pictures on the GPz 550 forum so I decided to run two threads.

To Do List: Valve cover gaskets is on the way, have to ID the race cams so I can set the valve lash correctly. Z-1 order for other engine gaskets etc.

 

[Guest]

subscribed!! Lots of fun mods on this bike, bet she's going to be crazy fast and fun for a 550. Are you using Z1 for all the engine gaskets?

 

[Big T]

looks good so far

Yosh pipes have a plate riveted to the can. Looks like the rivets are there

That thing will be a rocket.

As I mentioned before, get the Avons in 3.25/4.00 for the sharpest handling

 

[nvr2old]

Really cool bike. I've always loved the 550 GPz's. Great starting point. With only 3,000 miles since the rebuild, it should be fine, even after 27 years of storage. It'll be fun to see the progress.

 

[harley10]

Pipe looks like a Bassani to me ,very nice project,brian

 

[srsupertrap]

Thanks Guys! I am going to do my best with this little red rocket. Azr, I have already purchased an OEM valve cover gasket but the rest of the order I am sending to Chris @Z-1.

Okay what can I do on Monday night? Put up the Christmas Tree or clean the K&N Air Filters . . . I will do both

 

[Big T]

Pipe looks like a Bassani to me ,very nice project,brian

Bassani has big "ears" where the header meets the mid pipe

That looks just like my Yosh, a split on the mid pipe where it slides over the header and the two rivets on the end where the badge used to attach

 

[Guest]

What a beaut! I love the half litre bikes and the gpz is a sweet one. I'd like to add one to my stable. I bet this one screams too. Keep up the good work.

 

[Vmass]

Very cool bike!

Best of luck with the project.

 

[winfield]

subscribed

 

[srsupertrap]

Thanks Corey, azr, nvr2old, harley10, Vmass, Sci85, Big T & winfield and I hope everyone is enjoying this because its therapeutic for me.

I received the OEM valve cover gasket from Ebay so I decided to see what surprises are under the valve cover.

Here is a picture of the cam chain tensioner, no way this can be stock right? I probably go back to stock since I won't be chopping the throttle at 10K

I removed the plug wires from the coils and found the smucklehead didn't even install terminal connectors. All four are like that.

Man this thing has a lot of bolts securing it. I removed the 2.2 Ohm coils to make room for the valve cover removal. More room than a GS

Thumbs down to the Kawasaki Engineer for placing the cam chain bolt directly under the horn with no access to remove it

A quick tap with the mallet and the valve cover pops free

The oil galleys are dry but everything turns smoothly, I fill em up with dino for the time being. Cam lobes look perfect.

Okay, I need help here . . . What cams are these? M "symbol" E. One is marked R1 while the other is R2. They don't look to radical Oh yeah it's slotted cam sprockets.

 

[blowerbike]

modified stock tensioner...i'd keep it if the cams turn out to be anything much over stock.
put an indicator against the shim bucket and check the lift then compare to stock.
you may have re-grinds in it and they may be hard to identify.

 

[srsupertrap]

GSers & GPzers,
I could still use some help identifying the cams . . . I took some more pictures tonight so perhaps rapidray, Trip or someone could help identify these. Please have a look.

Blowerbike, How does one distinguish regrind cams? I don't see weld lines. Could be stock?

Photo of the slotted cam sprockets, exhaust looks to have moved. We can see R1 directly below the Intake sprocket bolt.

More views of R1 stamping

R2 marked on the Exhaust

View from the other side of the Cam Chain, I also removed the half moon gaskets but no significant marking. E is marked on the exhaust & 8 marked on intake

 

[JEEPRUSTY]

Is that and M E oriented logo?
Could be Moriwaki Engineering.

 

[JEEPRUSTY]

 

[blowerbike]

yes you would see the weld up from the side of the lobe.
i can't tell from the pics myself.
if you could measure the lift and compare to factory specs that would get you headed in the right direction.

also the casting letter's/numbers might not help.
look on the cam flange where the sprockets bolt on and look on the end on the cams.

also if the cams was of much increase in size you would see clearance work around the bucket's and maybe on the valve cover over the lobes.

lastly...
if the cams was degreed then the bolts can be anywhere in the sprocket slot...that may be where the exh. cam was set when installed.

 

[Big T]

Hmm, 615 kit, Moriwaki cams, mikuni flatsides, Yosh exhaust

That thing may be faster than your Suzuki

 

[srsupertrap]

Is that and M E oriented logo?
Could be Moriwaki Engineering.

Thanks JEEPRUSTY for posting that information, I will have a closer look when I get home tonight and try to take a better picture too

Okay, here is a stupid question is Moriwaki Engineering still in business?

 

[SailorJack]

Awesome thread. Always wanted a lil GPZ550. Stock though. All that aftermaket stuff is cool but I have no use for it. Plus it just complicates a restoration/rebuild.

Good luck though. Looks like you have all the help you could need here and on the GPz forum.

Subrscibed. Looking forward to the updates.

 

[Big T]

Okay, here is a stupid question is Moriwaki Engineering still in business?

Google is your friend

http://www.moriwaki.co.jp/global/

http://www.moriwaki.co.jp/global/partner/02.html