New GPz 750 owner -with questions

[tri650]

Just picked up a 82 Gpz 750 yesterday. Got a great price on this bike after the owner could not sell. This thing runs like a bat out of hell and is incredibly stable on the road. The only reason I say that is I also have a Concours (95) and that thing is moving all over the road at high speeds. The Gpz feels like it is glued to the road. Very impressed with performance - quick, smooth and not dead spots. Has a 4-1 kerker but the PO was not sure if any jetting was done. Hate to mess with it given that it is running so smooth.

The first thing I want to do is work on the front brakes and suspension. Both are weak. Basics will include new stainless lines, new fluid, pads, and springs/oil in the front. Is there a list anywhere that indicates what other parts from other models will fit the 82 Gpz. Particularly the front calipers - would like to find a dual piston set up as opposed to the single piston. Want to do some track days next year and want the stopping power.

Any other help or guidance is appreciated.

[raymond~]

the 82 GPz750 was a one-year offering but I recall that it shared interchange
some parts with the KZ750 of similar vintage. I don't remember that dual
puck calipers were available though. try changing lines and fluids and see
if that'll help with the front brake touch. my brakes are running DOT4 and
kevlar lines and it feels strong enough for me - great touch and modulation,
though not on par with the modern design.

coincidentally, i rode my 82 GPz750 for the first time today, after a 5+ year
hiatus. it was a happy reunion with an old friend, neglected due to work
demands, including the purchase of a ZRX1200.

sadly, I'll be selling it to a colleague shortly.

[WeBeToyz]

Since it is running so well take a look at your plugs to see how they are burning. If they are burning right no need to worry about the jetting. I did have to go to slightly bigger mains when I installed my Bassani pipe on my '82, but not sure about a KerZerker.

Many parts on the KZ are interchangable. One of the best things you can do is install an upper triple clamp from an '82 KZ to allow you to use handlebars. The original design of the separate handlebars sucks. They aren't really handlebars and not really clip-ons. I installed one, slapped on a set of down bars, and the difference was immediately noticable in handling and feedback from the road. It gives the bike a much better look IMO as well.

Other mods I did to the front suspension was to install a set of progressive fork springs and a fork brace. Rear suspension I installed a Cal-fab alum swingarm and a set of aftermarket shocks w/ resoviors. It wasn't uncommon for the stock swingarm's on these bikes to be sloppy in the frame and require shimming. You may want to check your tolerances. I also went with the biggest tires I could mount on the stock rims. Many opinions available on this but the bigger rubber really helped this bike out.

I installed the SS brake lines as well and the difference was minimal. The single piston calipers only work so well.

Another cool mod for this bike is to install a seat from a Lawson Replica bike. It mounts to the stock seat baseplate and lowers your center of gravity.

Good luck.

[klx678]

Originally Posted by tri650

Just picked up a 82 Gpz 750 yesterday. Got a great price on this bike after the owner could not sell. This thing runs like a bat out of hell and is incredibly stable on the road. The only reason I say that is I also have a Concours (95) and that thing is moving all over the road at high speeds. The Gpz feels like it is glued to the road. Very impressed with performance - quick, smooth and not dead spots. Has a 4-1 kerker but the PO was not sure if any jetting was done. Hate to mess with it given that it is running so smooth.

The first thing I want to do is work on the front brakes and suspension. Both are weak. Basics will include new stainless lines, new fluid, pads, and springs/oil in the front. Is there a list anywhere that indicates what other parts from other models will fit the 82 Gpz. Particularly the front calipers - would like to find a dual piston set up as opposed to the single piston. Want to do some track days next year and want the stopping power.

Any other help or guidance is appreciated.

Here's a shot of my adapted Honda dual piston caliper brake to a Yamaha.



I cut off the back half of the original mount bracket of the non-antidive caliper carrier from a VF500F (right side) made a .500" thick aluminum adapter and had a GOOD TIG welder weld it together. I cut it out a bit and filed it down.

You could also visit the Kawasaki parts schematics and do some research to see if the forks on the GPz were used on any later bikes that used twin piston calipers to find what might work. It'd just take a bit of "leg work".

[tri650]

Thanks for all of the tips and advice.

Here is what I have done so far. I ordered braided brake lines for the front. I have a master cylinder from a GSXR that I plan to use and run two lines from it directly to each caliper and eliminate the junction. I will continue to search for a double piston set-up that will work. I also found a 82 KZ complete triple tree on eBay that I bought so I can put on a handlebar. I will replace the front springs and I like the idea of a fork brace. I also want to find an 18" wheel for the front as the tire selection is much broader for this size. Someone suggested the later KZ1000 police bikes had the same spoke rim as the 550/750 but in an 18" - and it just so happens I found one on ebay. I plan on sticking with the front end as my first project and then moving back from there.

Took the bike out yesterday for a short spin and am amazed at how well it runs. Quick, smooth and a blast to ride. It just feels right. My ultimate goal is to make it track worthy and do some track days with it next year - and hopefully enter one of the AHRMA vintage races. Their vintage superbike category takes bikes up to 1982 and the 750 is classified in the "heavyweight" class. Lot of stiff competition in this class but I am resolved to the fact I will probably be the backmarker - but I will have fun.

Thanks again for all of the tips and info.

[tri650]

If anyone is still out there - I bought a used triple tree off ebay that supposedly fit a 82 KZ750. The triple tree that I bought is about 1/4 inch wider at the fork openings than what I currently have on the bike. Wondering if I was sent the wrong part or if for some reason they made the triple trees different for the Gpz and the KZ - not sure why. Not sure if the extra 1/4 will be a problem - I guess I could put in a spacer to make up the difference. Just wondering why they would be different.

[WeBeToyz]

Originally Posted by tri650

The triple tree that I bought is about 1/4 inch wider at the fork openings than what I currently have on the bike.

That doesn't sound right to me. I don't really understand what you mean by "wider."

There is an extra 1/4" between the openings for the forks?

[tri650]

Sorry - I meant that from center to center there is a 1/4" difference. The 82 KZ triple tree measures 7.5" from center of fork tube opening to other center. The Gpz measures a little less than 7 1/4" if I measure from the center of the fork tubes to the other center. I could tell right away the KZ top clamp was wider as the forks did not match up. I asked the question of other KZ triple clamps I saw on ebay and they all measured 7.5" or slightly larger.

[mannys85gpz]

i have a 85 gpz 750 i put a 2002 ninja zx6 swing arm rims tail light and forks with out any probs.