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Discussion Starter · #1 ·
How does it look so far?

I have been working (not really) on my 82 Gpz750 to turn it into a vintage racing bike. Rode it for a short time prior to winter setting in and was really impressed with the power.

Currently stripping front end and rear swingarm - plus brakes. Some parts are at powdercoaters. Plan on rebuilding front suspension and rear. Have had some challenges finding other parts that fit this particlular model - just my luck to buy a one-off model. Bought some 83 wheels off of ebay and hoping the 18" front will work. Need to find a source for bearings for front end. Also, need to figure out what springs to use on the front end.

Hoping the cold weather will encourage me to get into my basement and get this project moving. Plan is to have it ready for a track day in April.

I will provide progress as I move along.

Any help, suggestions, encouragement are welcomed.

 

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Good luck! I will follow this project because I have a Gpz 750 -83 with som 82 parts on it. Someone crashed it and replaced the front fork with a fork from a Gpz 750 -82. I have the 82 brakes too.
So please if you find information about upgrading or improving the front fork and brakes I´m very interested.
I found steelbraided brake lines on ebay for 69.99 $ for the front brakes. And also two new front brake discs for 180 $ on the uk ebay site. Both the brake lines and the discs were sold by company who manufacture them so I believe they are available.
And if you find information about where to brace the frame I´m intressed. I believe my frame have a few more pipes from factory.

/Karl
 

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Discussion Starter · #3 ·
Good to hear someone else out there with the same situation. I want to really tighten up the front end. Looking at new springs, new fork oil. Also tearing the front brake calipers apart and rebuilding them. I have purchased some braided brake lines that I hope will work. Will be getting the 18" front wheel this week. I also came across a couple of companies that offer front fork braces.

I am thinking that bracing the frame will be done in the usual spots. I will lay some things out and let you know. Keep my posted on your progress. Hopefully we can help each other out.

Wally
 

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RaceTek cartridge emulators and straight rate springs are the mods usually recommended for the front end, unless you can get away with running a later model front end and wheel, in which case the Suzuki Katana 750 forks are better than any GPz750 forks, and the wheel is 17" so you can run radials. I used 99 GSX750 Katana forks, but I think anything from 88 on will work.
The 17" 750 Katana rear wheel uses the same size axle as the 83 GPz750.

And Works Performance rear shocks.
 

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Hi Tri650
i 'am new on here and i have just your photo i have just got a 82 gpz 750 r1 as a project and some one has cut off the mounting brackets for the tank and battary box do you have anymore photos off this area so i can try to work out were to mount them and the hight they need to be.am i right in thinking there are 3 6mm threaded hole end(2 for box and 1 for tank).
any help would be greatful
cheers phil
 

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Discussion Starter · #7 ·
Phil - let me look tonight when I get home. As i recall there is a bracket that goes across the frame that attaches to the tank and battery box. I will try and get some pics.
 

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good luck on your projects, folks. if anyone needs misc parts for the 82 R1, let me know. sold my 750R1 after 25+ yrs and I still have ton of spare parts, including complete motor with only 2k miles. 98144 Seattle.

meanwhile, the guy who bought my bike may call if a part is needed and I have so far, just found the part and given it to him (clutch cable, turn signal, seat, etc). hah hah, but i'd charge you, though it'll be fairly cheap. lemme know: [email protected] raymond-
 

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I'm trying to upgrade my front also. Racetech don't have this bike listed so I can't confirm which fork springs to get. Can anyone tell me the fork spring length for this model (1982 GPz750).

Off to do my intro now...
 

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Discussion Starter · #12 ·
I will be getting my parts back from the powder coater soon so I will also be interested in spring length. I am wondering if you could use something close and then make up the difference with spacers? Is this particular year/model so different from the 550 or other 750 years? I am by no means a suspension specialist but I would think we could get close and then tweak. I will give racetech a call and see if they can provide any guidance.
 

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I am wondering if you could use something close and then make up the difference with spacers?
I'm not a suspension specialist either but from what I've been able to gather, that is the approach that progressive uses. They make the progressive wound springs for the weight of the bike, then they use spacers (pvc or aluminum) to make up the difference between the new spring length and the stock spring length specs.
 

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StarGate is right on the money, many Progressive kits come with pvc pipe that you cut to size.

I bought a set of Progressive fork springs for my KZ750 twin on eBay, they were blister packed and no spacers were included. I already had a piece of schedule 80 PVC (overkill, but it's free) the right diameter so it was no problem to cut spacers.


Speaking of KZ fork springs, does anyone know if all KZ's had straight rate springs, or did some have progressive (not the brand but the way they're wound) fork springs? I have 4 sets of fork springs and two of them are progressive wound.
 

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I'm only about 95% sure on this because I've only have my springs out once, but I'm pretty sure mine have a slight progressive wind to them. And I know for a fact they are the original springs.
 

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According to this the 11-1104 is 19.12" (486mm) long and needs a 1.3 spacer. I'm assuming thats 1.3" which makes the maximum possible spring length 20.42" or 518.6mm.

I'm not a hug fan of the Progressive brand springs as the spring wieghts are pretty low. Being 105kgs (235lbs) and ride the poor girl pretty hard, I don't think they will be up to it.

Looking at the Racetech website, they have springs listed for the KZ1000 which are 500mm long. I'll probably just have to take into consideration the different in the weight of the bikes when choosing my spring rate.

Here's a pic (as I know we all love pics!!)

 

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B Dub, I have first hand experience with Progressive Fork springs, on a 79 KZ750B twin.
At the moment I also have Koni rear shocks (14 3/4" long!), and I weigh near 250 lbs, and the bike has 130/90/16 rear and 100/90/19 front, on tubeless Morris Mags. And 10 wt fork oil.

I put the fork springs on while still using a set of worn out 80 KZ750E shocks. Helped the ride out but the rear shocks were still messing up the ride. They'd bottom out crossing tracks or hitting bumps, and the shock would go right up my spine. The Koni shocks killed that problem, deader than the proverbial door nail, now I just glide over the tracks and bumps :)

My foot pegs, brake pedal, and shifter, are in the same location as yours (not surprising since I used GPz750 parts), because I like to bend the bike around corners. And it goes around corners better than it ever did before.
I have the sag set at 1.5" on the front.

Race Tech seems to favor straight rate springs, others favor progressive, pick the one you like :)
 

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Since that pic I've replaced the rear shocks (Hagon), which have helped out the sloppy rear end endlessly.

I've got SS braided lines waiting to go on, so the front forks are the final mod (for a while).

tri650, sorry about the thread hijack...any progress on your bike?
 

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How does it look so far?

I have been working (not really) on my 82 Gpz750 to turn it into a vintage racing bike. Rode it for a short time prior to winter setting in and was really impressed with the power.

Currently stripping front end and rear swingarm - plus brakes. Some parts are at powdercoaters. Plan on rebuilding front suspension and rear. Have had some challenges finding other parts that fit this particlular model - just my luck to buy a one-off model. Bought some 83 wheels off of ebay and hoping the 18" front will work. Need to find a source for bearings for front end. Also, need to figure out what springs to use on the front end.

Hoping the cold weather will encourage me to get into my basement and get this project moving. Plan is to have it ready for a track day in April.

I will provide progress as I move along.

Any help, suggestions, encouragement are welcomed.

Looks dusty! :smile:

Put some paper towels or rags in the intake and exhaust ports if you haven't already.
 

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great thread,good luck,any progress with that aluminium handlebar replace?
cause i have this same problem with my gpz r1.
 
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