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Discussion Starter #1
I recently bought a 83 GPZ 750 after having quit riding 15 years ago. My last street bike was a brand new 1981 GPZ 550. I saw it on the cover of Cycle World, and had to have it:D

My youngest son started riding a couple of years ago, and I got the fever again (with a little persuasion on his part). The GPZ is in great shape, has a 4 into 1 Kerker and new paint.

Is it just me, or do these old bikes handle terribly? I understand it's a 25 year old bike, but it only has 15000 miles. My son rode it and said it was "scary". I know a 25 year old bike isn't going to handle like his 600RR, but......

I searched around and found this:
GSX-R Suspension Swap

Is this the same guy, or swap done bya member on here? I was wondering if a newer swingarm would fit easier as stated in the article?

Heres some pics of the bike, and with my sons bike:





 

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When you mean scary, do you mean front end or back end? It might be as simple as changing fork oil weight, or a new monoshock in the back.

Hopefully someone with more experience will answer you soon. Welcome to the board.
 

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That suspension swap sounds like a lot of work. I'd replace the rear shock with an aftermarket damper, do a little work to the original fork and call it a day.

If I had any engineering and welding skills, then I might add a few carefully-placed braces to the frame, too.
 

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Discussion Starter #4
I think I read somewhere that the "anti-dive" in the forks is worthless. It seems that the bike has zero lean angle. It feels like the rear to me, but my son thinks it's the front. Any idea where I can get a new rear dampner?
 

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Gimme more twisties
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I've been on an '85 GPZ600r for some time now and haven't any complaints with the handling.
Of course the oldies aren't as sophisticated as the new ones but they're definitely not scarey or terrible in my view.
I'd have a good look at suspension and tyres before I'd write it off as a dog.
Does it have the air front suspension ?
If so you could check to make sure somebody hasn't pumped it up too hard ( a common mistake ). I believe about 6psi is enough.
Good luck with it anyways
 

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I think I read somewhere that the "anti-dive" in the forks is worthless. It seems that the bike has zero lean angle. It feels like the rear to me, but my son thinks it's the front. Any idea where I can get a new rear dampner?
Whether, or not, the anti-dive is worthless depends on what you expect from it. The old Kawasaki system actually did its job well when it was properly maintained, but that was the problem. Doing its job well screwed up other aspects of the bike's handling. I took the anti-dive off my bike and was immediately pleased with the result. Keep in mind that there are probably other things you could do to the fork that would improve its performance, as well.

You can probably get a good shock from Works Performance for $500.00-$700.00 If they don't make a shock for your bike, then they might be able to re-build the original unit.
 

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Discussion Starter #9
Whether, or not, the anti-dive is worthless depends on what you expect from it. The old Kawasaki system actually did its job well when it was properly maintained, but that was the problem. Doing its job well screwed up other aspects of the bike's handling. I took the anti-dive off my bike and was immediately pleased with the result. Keep in mind that there are probably other things you could do to the fork that would improve its performance, as well.

You can probably get a good shock from Works Performance for $500.00-$700.00 If they don't make a shock for your bike, then they might be able to re-build the original unit.
Is there any thing in particular I need to know to remove the anti-dive? I figure I'd replace the springs with Progressive.
 

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Is there any thing in particular I need to know to remove the anti-dive? I figure I'd replace the springs with Progressive.
Firstly, I should tell you that I am definitely not an expert on the matter. I just know what worked on my bike. On my bike, an '85 Ninja / GPz900R, I removed the external components from the fork tube and covered the corresponding attachment point with an aluminum, "block-off" plate approximately 6mm thick. Removing the external components revealed two holes in the fork leg. Fork oil needs to flow freely between these holes, so, I connected the holes with a channel carved into the fork side of the plate. I cut the channel about 3mm deep and a little bit wider than the diameter of the holes. I sealed the channel with an o-ring. All things considered, it was a very straight-forward mod., but it didn't solve the fork's other problems. I took care of those later.

I'd recommend a fork brace, some new, straight-rate springs (matched to your weight, of course) a pair of cartridge emulators and a good, old-fashioned rebuild (new oil, seals and bushings). You would probably be surprised at how good you can make the stock fork work. A company named Race Tech can probably hook you up with everything but the fork brace.

Also, if you don't already have a good, factory manual, then get one. They come up on Ebay from time to time. Believe me, they make things a lot easier.
 

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Red is Faster
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it looked to me like your eccentric cam/chain adjuster is upside down. at least it would be on a 1100...750 might be different...
 

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Red is Faster
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Also, don't go by those marks on the swing arm and cams until you check to see if the rear is aligned. That’ll mess up handling too
 

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Eddie Lawson is God!
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Want to descarify your bike?
Lube and adjust steering head bearings. USE THE MANUAL METHOD. Then perform a fallaway adjustment. You won't find in a Jap manual, because it's done on HDs. Take your forks, replace seals, use 15wt oil, discontinue the air and CAN the anti dive.
Disassemble, clean and lube the rear suspension linkage. They usually were dry from the factory.
Install Bridgestone BT45v tires in the STOCK sizes. Axe the 20 year old rubber on it.

The eccentric chain adjuster....If the axle is BELOW the centerline, ride height is increased and rake is decreased. Scary unless a motorcycle factory is paying you to ride their bikes.
 

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Discussion Starter #16
Want to descarify your bike?
Lube and adjust steering head bearings. USE THE MANUAL METHOD. Then perform a fallaway adjustment. You won't find in a Jap manual, because it's done on HDs. Take your forks, replace seals, use 15wt oil, discontinue the air and CAN the anti dive.
Disassemble, clean and lube the rear suspension linkage. They usually were dry from the factory.
Install Bridgestone BT45v tires in the STOCK sizes. Axe the 20 year old rubber on it.

The eccentric chain adjuster....If the axle is BELOW the centerline, ride height is increased and rake is decreased. Scary unless a motorcycle factory is paying you to ride their bikes.
Ummm, what's a fallaway adjustment?
Any idea's on how to can the anti-dive?
I have no idea how old the rubber is...but I'll replace it.

OBTW, your myspace page is friggin hilarious. Sound kinda like me. I'm 50 and after 24 years in the Navy, quite grumpy cause I'm finding after a year and half, I'm not to thrilled with civilian employment. ;)
 

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Flipping the chain adjusters is an old trick. I've had mine turned both ways. For street riding the benefits aren't enough to worry about but I never noticed any bad handling traits when they were upside down. Have you checked to see if the air assist on the shock and forks is holding air and what pressure they have if they are? I rebuilt my stock forks (yes, my anti-dive actually still worked) and used 15 weight oil with 10 lbs. of air front and rear. Anti-dive on 3 and shock preload on 4. I have embarrassed many newer and faster bikes on this old relic when the roads got curvy. The correct way to completely disable the anti-dive is listed above. Do you have a manual for this bike? If not, PM me your address and I'll see if I can scrounge one up. I should have a couple lying around.
 

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Discussion Starter #19
Flipping the chain adjusters is an old trick. I've had mine turned both ways. For street riding the benefits aren't enough to worry about but I never noticed any bad handling traits when they were upside down. Have you checked to see if the air assist on the shock and forks is holding air and what pressure they have if they are? I rebuilt my stock forks (yes, my anti-dive actually still worked) and used 15 weight oil with 10 lbs. of air front and rear. Anti-dive on 3 and shock preload on 4. I have embarrassed many newer and faster bikes on this old relic when the roads got curvy. The correct way to completely disable the anti-dive is listed above. Do you have a manual for this bike? If not, PM me your address and I'll see if I can scrounge one up. I should have a couple lying around.
I have a Haynes manual. I'll PM you my address, I can't find a factory one.
 
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