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ZXR Forks onto GPZ
Posted: Sun Nov 20, 2011 11:22 am
Author: RUDDY
Forgive me if this is a stupid question as I have a lot to learn. I am considering options for my GPz550D1 resto, one option is standard build the sevcond is slightly modified, this months Practical Sportsbike as a lovely modded ZRX400 featured and its making me lean to the modded route.
So, does anyone know if ZXR400 USD forks and stanchions would fit or be safely made to fit the GPz ?
Cheers, Paul
Posted: Sun Nov 20, 2011 11:36 am
Author: kas750
Hi Paul...
The zxr forks are certainly a common mod on all typres of special.Another front end to consider is from an rgv250.
On the right is a kh250 with an rgv250 front and rear end and H1 500 engine.
The bike on the left is a kh250 with h1 engine.The front and rear end are from a cagiva!!!
The point i am making is you can make owt fit owt..Sorry...thats not much help is it?

Posted: Sun Nov 20, 2011 12:08 pm
Author: garyd
Isn't the big issue that USD are shorter than RWU.
So you either have to lengthen them or get a custom top yolk made to reach down.
Posted: Sun Nov 20, 2011 12:18 pm
Author: coldsummer
Paul, like Kas750 said you can fit anything really but you will need to consider getting a new stem made in order to accommodate the gpz bearings. Also issues around the difference in fork lengths which will affect the steering geometry so you may need to get the donor forks lengthened which will involved fork top extenders and internal spacers. Modern forks tend to have less offset so you may also need to alter the steering stop mechanism to prevent the forks hitting the tank on full lock, yet you still need to to retain a useable turning range. Smaller issues may be encountered with matching up the speedo drive arrangements and accommodating modern brake master cylinder and possibly switchgear.
So, it may be a lot of work unless you are lucky enough to find a front end with similar dimensions as the GPZ's. Hope I haven't dampened your enthusiasm too much.
Posted: Sun Nov 20, 2011 12:20 pm
Author: coldsummer
garyd wrote:Isn't the big issue that USD are shorter than RWU.
So you either have to lenthen them or get a custom top yolk made to reach down.
That is one of the problems Gary. A stepped yoke can be made, I recently had a custom set of yokes/stem made up for my 'number seven' project and it wasn't cheap.
Posted: Sun Nov 20, 2011 12:34 pm
Author: andyb1962
kas750 wrote:.
On the right is a kh250 with an rgv250 front and rear end and H1 500 engine.
The bike on the left is a kh250 with h1 engine.The front and rear end are from a cagiva!!!
Very tasty ............................ i want one

Re: ZXR Forks onto GPZ
Posted: Sun Nov 20, 2011 9:02 pm
Author: compo z1r
RUDDY wrote:Forgive me if this is a stupid question as I have a lot to learn. I am considering options for my GPz550D1 resto, one option is standard build the sevcond is slightly modified, this months Practical Sportsbike as a lovely modded ZRX400 featured and its making me lean to the modded route.
So, does anyone know if ZXR400 USD forks and stanchions would fit or be safely made to fit the GPz ?
Cheers, Paul
paul not a problem u need the 43mm top and bott yoke's and modd the stem to fit as this pics,
these have been made to fit all zeds from 750-up.

Posted: Sun Nov 20, 2011 10:05 pm
Author: RUDDY
Cheers guys, few sets of zxr forks on ebay, may get a set and play with them when the frames bare, guess I would then need decent rear shocks to complement the front.
Cheers Paul
Re: ZXR Forks onto GPZ
Posted: Sun Nov 20, 2011 10:28 pm
Author: z650freak
these have been made to fit all zeds from 750-up.

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What length are the zxr forks???
Posted: Sun Nov 20, 2011 10:38 pm
Author: nigel bessant
RUDDY wrote:Cheers guys, few sets of zxr forks on ebay, may get a set and play with them when the frames bare, guess I would then need decent rear shocks to complement the front.
Cheers Paul
Paul, you could try buying a complete ZXR non runner and selling the parts you don't want, you will probably sell all the unwanted parts for what you bought the bike for and end up with a set of free USD's.
Worth a thought. That's what I did but it takes a few months to get rid.
Posted: Mon Nov 21, 2011 2:03 pm
Author: floydsz1
one of the zx9's (cant remember which model it was) came with usd forks while the other models are rwu ones. im sure the usd ones are longer than most usd forks from other bikes. That would keep the ground clearence ok.
Posted: Mon Nov 21, 2011 7:37 pm
Author: garyd
Weirdly it was the first models of ZX9R that had the SD...94 -97 B model.
The C went normal to save weight.