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GPZ750R fighter advice required.

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47K views 142 replies 22 participants last post by  exuptoy  
#1 ·
My Triumph build is on hold for now and I have decided to fighter my standard Gpz750R which is currently residing in my garage.

I have just purchased a ZX9-R (B model) swingarm and wheel which I am hoping I can gety to fit without too much work and was wondering will I need a ZX9 B shocker or is there something else which fits the frame and the arm with minor or no work required.

Has anyone fitted one of these arms to a GPZ9 or GPZ750 before or a ZX6 front end.
Here is the bike in it's current state. I hope to fit ZX636 B1H upside down front end next once the arm is done.

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#2 ·
Well, got hold of a 1999 (I think?) ZX6 front end on ebay for £52 (damn sight cheaper than an USD one) and decided to start fitting it.
Got the old one off this morning and just to trial fit it, I tried it up for size. Now without removing the top fairing yet to check the fit at the base of the head
bearing, it does seem to fit ok, although the top thread doesn't seem to protrude much from the bearing (not even enough to get the 2 castellated locking nuts back on.
Does anyone know it the lower bearing is the same size on the GPZ9 and ZX6 front end, as physically it does look slightly wider but my vernier was paying up. Personally I reckon the bearing is incorrect. Any opinions?

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#4 ·
Go to 750turbo.com and the how to section. There is info about swapping a zx9 front as well as some 6r rear end parts on there. The water cooled 750&900 frames were close to the air-cooled ones and the steering neck I think is the same. The only front I have personally seen on one of those was a zx11
 
#6 ·
The 83-85 GPz750 ( air cooled, double craddle frame ) is not the same bike as the 750R or 900R ( Liquid cooled, diamond frame, engine is stressed member )

There is a guy over on gpzzone.co.uk site that has fitted a ZX9 swingarm...TON of work as the ZX9 arm has an offset shock and the GPz900 is centered. Also the frame is unique on the GPz900/750R's as the centre of the swingarm is where it bolts up to the frame....not the outside as per almost every other bike.
You can modify ZX11C and ZX11D arms to fit, and ZZR1200 should be able to be modded easily enough as well. Gotta cut the center out of the pivot bolt area....think its 128mm out of the center and that leaves 64mm or so on either side. Lots of work no matter which swingarm ya use, lots of cutting/machining needed. On a positive note, if you dont require a fatter looking swingarm, the stock arm will take a 180 tire on a 17" wheel.

I just picked up a set of ZX636 forks and wheels to swap onto my GPz900R, and looking for a ZX11C swingarm in the classifieds here. Next winters project, if I get the KZ done first lol.

You should join gpzzone as its dedicated to these bikes and there is a ton of bike specific info. Its hard to find info on these anywhere else.

This is the GPz900R/750R swingarm...notice the center section, this is the frame area the pivot bolt passes through.

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#7 ·
Yes you are right but im talking about a front end swap(and i was posting from my ipod which is a huge pain:)). As far as the steering stem/front end swap is concerned they are practically the same. And the info on 750turbo about using zx6 parts deals with swapping a 180 into the stock arm which past the pivot on the 750R/900 is the same as the older air cooled ones right down to the I beam section and eccentrics. I wouldnt mess with an arm swap personally but m357 posted some great info on it.
 
#8 ·
Shift is right, the front end swap will be the same between the two. And there is a ton of info on 750turbo.com, which is free, where the gpzzone requires a yearly member fee to join. This is an issue that all fork swaps face though, ussually requires the same mods to fit...steering stem swap, custom stem, or if your lucky a set of bearings will do the trick. There is lots of info right here on CF to help ya out with this.

The swingarm poses its own very unique issues with this model, and info is hard to come by on the rear swap. I'm seriously thinking just swapping a 17" rear wheel into the stock arm is the way to go. And this info is also readily available on 750turbo.com as shift pointed out.

Rep for ya Shift :)
 
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#16 ·
I'd like to fit the earlier bodywork but just don't know what to do. I have just bought a single seat RGV tail plastics from ebay so I wanna see how that looks first. Also a m8 has a complete RGV back end including lights and both seats so if the plastics look good then I'll get the back end from him. I reckon the more rounded usual suspects like 916/MV/Gixer as too curved for an older angular design so the boxy RGV may suit it.
 
#24 ·
The stem has now been pressed and should be turned down tomorrow. I decided to bin the Nexus and then had a little brain wave. Decided to take the Nexus off and dug out the street triple stuff and then offered them up for size. i just need to sort out the link pipe then the jobs a good un.

I think I will modify the subframe a little as well to get the seat in closer to the tank and visually shorten the overall length of the back end. I reckon about 20-30mm should do it then it should be a better fit at the seat/tank join, I may then blend the tank in a little where the old seat used to join the tank.

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#26 ·
I like the tail but i think the mufflers are too big for this bike. They just dont match that well.

As far as the tank goes you will have to pull your tank off and measure how wide the frame gets. Your frame isnt a traditional backbone style frame so to get a tank on there like an old z tank would be a lot of work making a new tunnel for the tank. The frame is not quite a perimeter frame so fitting tanks from bikes that had one is also a big challenge.
 
#27 ·
Taste is subjective I suppose, even on the street they are too big, and that's why there is a large market for aftermarket ones. Maybe if I do go down the ZX9R B arm route at least it may be in proportion.

The thing is on modern bikes, underseat exhausts are now in the main so at least on a retro bike it will be a talking point and leave the ZX9 wheel (or arm) in full view.
At least if the pipework is complete I then get the option to change for something else. Like the ones here.

With regards to the tank, on reflection I think I may well leave the GPZ one on and blend in the back of the tank when I have the subframe and seat where I am happy with it.
Thanks for the advice tho as it's always nice to get some further thinking on it. I will also remove the lower fairings and get hold of a ZRX bellypan or something similar to break it up.
We'll see as it grows I suppose.
 
#28 ·
On a brighter note the stem has been turned down, the yoke has been faced back and a modified land has been machined as a bed for the lower bearing. Here's the result. Sitting back on the bike now awaiting new standard taper roller bearings. At least now the lower bearing will have a rain and dust seal as the previous ZX6R bearing was full of rust.

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#29 ·
Altered the angle of the seat to measure the amount which needs removing from the lower subframe mounts and I think it looks better and more natural. Also loosely mounted the front end until I can get my new bearings delivered, now that the yoke is complete.
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#32 ·
My bearings arrived today so I fitted the taper shells in the headstock with the bearing press tool. I found that the stem is too short to allow the lock nut to be fitted so that has gone back to my m8's machine shop to be modified a little more to allow it to fit safely.

I decided to use my spare Triumph bars and risers to the ZX6 top yoke and used the bearing tool again to locate the yoke to allow me to set up the hand controls and drill the bars for the control locating pins.

Hopefully the stem will be back in the morning and the front end should be finished.
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