1982 GPz-750 (KZ750R1)

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SonicVenum
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1982 GPz-750 (KZ750R1)

Post by SonicVenum » Wed Sep 04, 2013 3:24 pm

Hey there, ladies(?) and gentlemen... I present to you my new project bike. My co-worker decided he was tired of storing it and was going to donate it, but decided to offer it to me because he knows I like to tinker with things of the mechanical sort (I've worked on my car at the company yard). It's in pretty good shape for the age. It's got about 33k miles on it. The seat will need a little attention from an upholsterer, but my co-worker knows somebody that can work on it. The tires seem pretty close to new and are Michelin Macadams. The paint is in ok shape, though it seems to have some kind of over-spray on it. I'll try to polish it up some and see if it helps. If not, the painted parts are easy enough to remove, so I might just repaint the whole thing. I only consider a different color because these bikes don't bring a ton of money, even when restored to original condition, so, why not?

My co-worker thought the bike was stock, but it's not. Here are the mods I saw at first glance:

Vance & Hines 4-1 exhaust (this was on my ZX-11 and I loved it)
Individual pod air filters
Rear fender delete (cheaply done, will need some work to better support the rear section and mount the plate more securely)

There are a few things that will need immediate attention before it's road worthy. My co-worker bought it in '06 and rode it for a little while, but then it just sat. When he tried to start it again after a long sit, one of the carbs leaked fuel. I'm guessing a clean-up of the carbs finished with a little SeaFoam through the tank should solve that. The brakes need to be looked at. The brake lever does nothing. It just flops around. The little window on the bar shows brake fluid, but obviously, something is not connected. The rear brake didn't seem to work either. I would imagine that the carbs have been re-jetted considering the air pods and the exhaust, but I guess I'll find out once I take them apart. If I use a rebuild kit, I should be able to use everything sans jets, correct?

On to the pics:

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Tetge
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Re: 1982 GPz-750 (KZ750R1)

Post by Tetge » Wed Sep 04, 2013 10:33 pm

So, you dragged the bike out of the Salton Sea and took it home? I suppose that it is an interesting project, although it is sometimes quite impossible to rebuild those carbs. It seems that the good old carb cleaners and boil out that we used to have, have been banned. And the new ones are not all that effective. But, the bike is cosmetically in pretty good shape, so, I shall be watching to see what you accomplish, although I still believe that your current bike is the superior machine.

mikedbike2002
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Re: 1982 GPz-750 (KZ750R1)

Post by mikedbike2002 » Wed Sep 04, 2013 11:21 pm

I had a 82 GPZ500 & it was a great bike at the time!!

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Brakelate
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Re: 1982 GPz-750 (KZ750R1)

Post by Brakelate » Wed Sep 04, 2013 11:53 pm

You too? My first "real" sport bike was a '82 Gpz550. Awesome bike with the electronic LCD display and Triple Disc brakes. First bike with Uni-Trac single rear shock. The motor and trans were sooo smooth!

The early '80s were great for new Japanese small (and big) bore bikes. I terrorized Turnbull Cyn on that little bike as well as Azusa Cyn and GMR....often into the early morning hours.

mikedbike2002
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Re: 1982 GPz-750 (KZ750R1)

Post by mikedbike2002 » Thu Sep 05, 2013 8:50 am

mikedbike2002 wrote:I had a 82 GPZ500 & it was a great bike at the time!!

DUH! I meant gpz 550!

SonicVenum
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Re: 1982 GPz-750 (KZ750R1)

Post by SonicVenum » Thu Sep 05, 2013 9:55 am

Tetge wrote:So, you dragged the bike out of the Salton Sea and took it home? I suppose that it is an interesting project, although it is sometimes quite impossible to rebuild those carbs. It seems that the good old carb cleaners and boil out that we used to have, have been banned. And the new ones are not all that effective. But, the bike is cosmetically in pretty good shape, so, I shall be watching to see what you accomplish, although I still believe that your current bike is the superior machine.
Not quite that far away. It was down in the Lake Elsinore/Murrieta area. With the help of a KZ forum, I already have a full detailed procedure for disassembling, cleaning, and reassembling these carbs, complete with color pictures and detailed lists of tools and products needed. They mentioned finding "carb dip" might be tough in some areas, so they gave a couple of suggestions for alternatives that should work. I saw one guy working on another project/restoration mention something about boiling parts in antifreeze. That's not top on my list of options.

Yes, I know the Rex is a better bike all around. It's 20 years newer, it's got 400+ cc more displacement, its mileage is a little lower, it's cosmetically in much better shape. But, that's not the issue. This bike was free. I don't really need one bike, let alone two. So, if the GPz is comfortable and I can make sure it's reliable, and can make it look good, it would be the one to keep, merely because I'd get more money selling the Rex than I would the GPz, even if I made the GPz look and ride better than new.

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xbacksideslider
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Re: 1982 GPz-750 (KZ750R1)

Post by xbacksideslider » Fri Sep 06, 2013 12:57 pm

Congrats.

Gas leaking means that a float needle is stuck - old gas will do that. Typically, the pilot jets are also a problem; I have the same model carbs on my GSXR and with the shit gas imposed upon us by those who know better - CARB, the tiny holes in the pilot jets will clog in a month or two if I fail to take her out for a spin. I suspect that the bike's vacuum petcock allows some gas to get by that shouldn't. Anyway, you might find that a selection of fine wires sourced from electrical cords will get the job of clearing the pilot jets done. As for carb cleaner, even back when I resurrected the bike after 15 years of sitting, I never needed anything stronger than aerosol carb cleaner.

Also, before you even sit on it, take some fine steel wool to those aftermarket/period rear shock shafts; rebuilding them ain't cheap and little specks of rust on the shafts will cut the seals. Hard to do without removing the springs but it can be done. Front forks too.

I'd worry about the paint later, get the mechanicals sorted first; besides any patina is better than none.

Oh, BTW, I'm envious.

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Brakelate
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Re: 1982 GPz-750 (KZ750R1)

Post by Brakelate » Fri Sep 06, 2013 1:45 pm

I was going to say I had a set of those Macadams on my second or third '85 Honda VF1000R. When commuting going into the winter season, I decided to go away from my regular racy tire choices and go with a harder compound "all season" type tire. I was pleasantly surprised to find that they had very nice grip, long wear and if I remember correctly had a nice linear "tip in" feel. That may have been from the narrow sizes those bikes run, but it stands out in my memory based tire catalog.

I imagine those have a build date of the mid-90's and it all depends on how they were stored, how much exposure they have had, etc. So each tire has to be evaluated on it's own merit. But when new, they were good.

That bike is a gold mine in parts alone, IMHO. If one were to part it out ebay style, you could make some serious money. Or sell it whole and let one of the many fanatics of the bikes of that era do it. For what you have into it, at this point it is all profit. My logical voice would caution you not to mess with it, as it has huge potential to become a "money pit". Especially since that particular make and model holds no special emotional value to you. From a wrencher / biker standpoint, it sounds like a great project. But the investment is usually best left for those who are trying to get back and re visit that special time and place and thus becomes something that only that one person can put a price tag on.

That bike is amazing in that it is whole and only slightly molested. The pipe and pod filters seem to be later than the mid to late eighties. Again, I would say early '90s. But, if they put a pipe and pods on it, I would bet good money they also rejetted it to match the combo as properly jetting one of those notoriously lean factory carb set ups would gain more than the pipe and filters alone.

My inner voice is trying to tell me of something in regards to that models steering head bearings. The 1100 and 750 had some issue with them and handling issues, but I can't recall exactly what. Just to be safe, search around that dedicated KZ site and see if there is something that pops up. ;)

SonicVenum
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Re: 1982 GPz-750 (KZ750R1)

Post by SonicVenum » Fri Sep 06, 2013 2:29 pm

xbackslider, Thanks! I'll see what it takes to get the carbs clean once I have them apart. And thanks for the tip on the shocks/forks. I'll take a look at them. The good thing is the bike was stored in a garage under a cover, not out in the elements. Right now, I have it under a cover and under a canopy. Hopefully, it'll be in a garage within the next few months. I'll definitely be focusing on the mechanical side first, making sure the bike rides well.

Jay, thanks for the tire tips. Figures the resident tire guru would have experience with these tires. Lol. I'll check the tires for build date next time I'm there. I was thinking the same thing about the visible mods being indicative of re-jetting. From what I've found on the KZ forum, the stock jetting and airbox will do just fine with an exhaust upgrade, but the stock jets are not recommended for pod filters. I suppose I could part the bike out, but that would take time, maybe even a lot of time. The bike is complete and doesn't have any irreparable damage, so I think it's worth keeping. As to the investment I'll have to put in it, according to the tips I've gotten from the other forum, all I'll need for the carbs is fuel bowl gaskets, o-rings, and carb cleaner and/or carb dip. Then I have to troubleshoot the brakes. The rest is cosmetic. I already have all the materials I'd need to polish up the bike and if I decide to paint it, I could do it myself with quality materials for around $100. And, thanks for the heads up on the suspension thing. I'll poke around and see what I find.

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Re: 1982 GPz-750 (KZ750R1)

Post by jhwalker » Mon Sep 09, 2013 8:58 pm

Free? Free! Looks like a fun project. :clap:

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