1981 Kawasaki GPz550: Restoration

[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]

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?

[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]

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?

[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

[Nessism]

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

[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]

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]

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

[GS1150Pilot]

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

[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

[srsupertrap]

And how much was taken off each side? And how much is left as far as wear limit per the service manual? I am not familiar with what the original thickness and wear limits on nthe GPZ is so that why I ask.

Chuck,
There is no perfect solution because Kawi OEM discs are either not readily available or they cost $250. The next option would be to find a used one on EBay and hope for the best. Next spendy option is aftermarket manufacturers but that could quickly top $500 if you replace all three discs and then they don't look original. . . So to answer your question

Specification Limit 6.00mm
Rear Disc (Now): 5.38mm

I am happy with my decision and will remember to use the front brakes more often.

[nvr2old]

I have Conti "Blitz" tires on my S model. I like the round profile on them but I'm a bit disappointed in the handling. They never feel completely planted..not the most confidence inspiring tires. The best tires I ever had were Michelin Macadam 50's. LOVED those tires. Had them on every bike I owned. Can't seem to find them anymore which is why I went with the Continentals on the S. The Avon Road Riders on my 400F seem very good so far, too.

[tkent02]

I had a Sport Demon on the front of my 650G, it was sticky but I couldn't really test it aggressively, there was a Spitfire on the back, it was not so sticky.. When I finally put the Roadrider on the back the Sport Demon was pretty worn, but it was still plenty sticky.

I would be happy with a pair of either one.

My experience with Sport Demons is that they are rather soft compound (compared to Metzeler that I typically use).

Choice of tyre is also dependent on how / when you ride.

Both Bridgestone and Pirelli I tried had better traction when cold and in the wet but the centre of the tires wore out too quickly compared to Metzeler. With properly inflated and warmed up Metzelers I never had any slippage even when pushing the GS850 to the limits and they gave me better mileage than either Bridgestone or Pirelli.

We don't get Conti's here I don't think.