1981 Kawasaki GPz550: Restoration

[srsupertrap]

Before I could paint the header & muffler, I tried to straighten the header down tubes which kissed a speed bump or something

I used a steel flared pipe which luckily was just about the right size & the influencer

After

That wasn't so bad compared to straightening out the header flanges which were concaved inwards. It will be black on Sunday

 

[GS1150Pilot]

I loved my GPz 550. My first project streetbike. Such tough little mothers.

 

[srsupertrap]

GPz wheels came back from powder coater today. Still have to polish the rim lip. Sand the lip with 1500 wet then Blue Magic?

 

[Nessism]

Blue Magic is for chrome. You need Mother's for aluminum. Don't think you need to go finer than 800 either, unless you are after a chrome look.

Wheels look great by the way!

 

[srsupertrap]

Installed All Ball bearings with new seals. Not very impressed because after driving the bearings all the way in the wheel bearings wouldn't turn. Pried the spacer to the side, tapped the bearings out a smidge and everything was okay.Wet sanded the rims yesterday with 400, 600 & 1000

Installed tires Conti today and managed to seat both tires with a bicycle air pump. I will drop them off this week at the local shop for high speed balancing.

Fork caps are retained with circlips . . . kinda cheap. I was hoping for progressive suspensions springs but the fork oil was clean.

 

[Nessism]

The wheels look great Steve. What size tires did you go with?

 

[srsupertrap]

Ed,
I went with the stock sizes: 3.25-19 (F) and 4.00-18 (R). Now I know why there are few stock GPz chain guards out there. Most people notched them to make room for bigger tires or just removed them

BTW, if anyone Forum members happen to see a 81 GPz550 seat or parts bike send me a PM. Those seats were a one year wonder . . . rarer than GS1000S mirrors.

Thanks
Steve

 

[srsupertrap]

My front brake M/C was leaking a bit past the piston assembly. I would prefer to keep the original M/C and just replace the guts but not sure if the bore look salvagable? It's not pitted but the brake fluid very rusty as you can tell by the rust stains.

It's a 5/8" bore. What do you think?

 

[Nessism]

I think if you were to clean up that master you will find pitts in the metal. Maybe try some 800 grit sandpaper rolled into a tube and see how it looks. If you get lucky and there are no pitts, then I'd slam in a new OEM piston kit and paint the outside.

 

[srsupertrap]

Well this project has not been exactly lucky . . . but I rolled up some 1000 grit on a wooden dowel and cleaned up the bore this morning and here are the results. I do have pitting evident in the M/C bore and it worse on the bottom than the top

Here are a couple of photos after showing the current state. Not horrible but there is pitting between were the two M/c plunger rubber seals reside in the bore in the uncompressed position. Questions below . . . .

Question:
1. Worth trying to repair it & hope for the best
2. If repairable how long could I dip the entire M/C housing in Berryman's to degrease it before it attacks the sight glass O-ring?

 

[blowerbike]

i have a functioning 81 GPZ1100 5/8 master...just ugly from fluid damage.
not sure if it's the same.
my 82 took a different master so i changed it out.

 

[srsupertrap]

i have a functioning 81 GPZ1100 5/8 master...just ugly from fluid damage.
not sure if it's the same.
my 82 took a different master so i changed it out.

Thanks! I wonder if the master bore has the same issue as mine?

I just checked the Kawasaki fische and the 81 GPz550 does share the same master with the KZ1100-B1 GPz (1981) p/n 43015-1081. BUT Kawi also lists a KZ1100-B2 GPz (1981) which uses p/n 43015-1085. Looks like the difference is were the brake line attaches to the Master. The one I have on the GPz550 looks like this

 

[blowerbike]

mine was working fine but the banjo attached to the end of the mc and caused fairing/fork cap clearance issues..
for my 82 the banjo should have attached in the front.
the one i removed looks like the one on the fiche above.

 

[blowerbike]

my mc window looks like glass..not fogged up or hazed/cracked.
no road rash or leaks...just bad paint plus after i bought my bike it got the super gunk and pressure wash treatment with all the body work removed.
the high pressure removed a lot of the bubbled up mc paint.
three pics coming.

 

[blowerbike]

and another..

 

[blowerbike]

and the last one..

 

[Nessism]

I bought two used masters off ebay that turned out to be junk. It's hard to find units that are not corroded inside. In the end I bought a master from an EX650 Ninja. Nice unit. Reservoir angles down a little which looks a little funny with the bars I selected, but think it's okay. Came off a late model bike so no corrosion too.

 

[blowerbike]

I bought two used masters off ebay that turned out to be junk. It's hard to find units that are not corroded inside. In the end I bought a master from an EX650 Ninja. Nice unit. Reservoir angles down a little which looks a little funny with the bars I selected, but think it's okay. Came off a late model bike so no corrosion too.

so a working/non leaking mc can still be junk?
i only sell junk when i represent it as such.
well i don't want to sell a member here junk thinking it's not.
what should i do?

 

[Nessism]

so a working/non leaking mc can still be junk?
i only sell junk when i represent it as such.
well i don't want to sell a member here junk thinking it's not.
what should i do?

Take out the piston and inspect for pitting. A good bit of work for a seller, but I don't know any other way to assure the bore is good.

Repeating this story but...sent some guy on ebay as message asking if they would be willing to pull the piston and inspect, and a short time later Joe Whelan wrote me back and provided photos too! Small world, and great service by Joe!

 

[srsupertrap]

so a working/non leaking mc can still be junk?
i only sell junk when i represent it as such.
well i don't want to sell a member here junk thinking it's not.
what should i do?

The piston comes out pretty easy, the piston is not secured by a snap ring ala GS but rather the white plastic part (14008) which has two tabs that engage the master cylinder housing. Press those two tabs in and everything sort of follows