Z800 Cafe Fighter Chopper thing GEOMETRY SPECS

Hi all.

Been pointed over as a good place for al things Z.

Thought I'd share my project here as hoping everyone will chip in with useful advice. I'm good with the spanners but no fabrication tools etc and more of a car person. I'm basically a guy with a Z and a vision!

So here's my current bike. A Z650, original with a few taken off parts, clocks, blinkers etc - I like the clean look.




Here's what it will become.

The Black Gold®


Lawson Kawasaki Race Green



And possible mono-shocked version.



As you can see, I love the stripped out short tail look but with clip on bars and fat rubber. Hence the Cafe/Fighter/racer/Chopper name.

This started out as a rebuild of my original bike but as these machines are quite simple and I was going to change so much, I figured I'd just go from scratch and do something new. So I have sourced a D2 frame, ZX900R Alloy swingarm, tank and tail and some better rear shocks. Odd bunch of parts but this way I can get the rear end all set up, shock mounts welded on and hide the rear torque tube inside the swingarm. I'm after a super clean look but it's very important I maintain the bikes original handling so there will be some (costly) trickery to achieve that.



The swingarm mods are to accept a wider 150mm rear wheel and for looks also. It will be powder coated black with the eccentric insert anodized Gold. I like this swingarm as it's not too modern looking and has a clean axle adjustment area.





Rear shocks are freshly rebuilt Ohlins. Gold works well.





Wheels also ordered and being built. Stock SuperMoto basically, 17 x 4.25 rear and 17 x 3.5 Twin Disc up front.



Should look like this fitted - I want a super minimal rear Caliper too - no big torque arms visible etc.




I definitely want Dunlops on there with the big white logo on, like the huge logo'ed F1 tyres of the 70s/80s.





Which brings us to the forks. I have a very clean set of 2006 ZX6R Ninja forks, as I wanted radial brakes. These are only .5" off in length from original Z650 forks but when you factor in clip ons I have lost 30-35mm of front end height, exaggerated by a smaller wheel. So I have designed some special yokes and am currently waiting to hear from various CNC shops in UK and China. Costs have been ranging from £350-600 per yoke. The spec is 7075 or 6082 forged alloy so good stuff.

This design restores near enough original steering geometry and also gives clearance to 50mm fork legs from fouling the tank. There are options out there but they are ugly and look very obviously aftermarket. The offset affects the trail slightly but there's not much I can do about that.




Forks. The 2006 model year saw the switch to Showa made forks and are supposedly much better than the previous model. Whatever - they're Gold!




Brakes will be Brembo front and rear, rebuilt and powder coated Black. Grabbed this nice little Brembo rear caliper for next to nothing. 4-Piston Radial Brembo fronts on their way.



I will replace as much hardware across the entire bike as I can with Gold Nitride Titanium fasteners for some nice finish detail.


So that's where I am now. I am basically design and assembly and heavy duty fabrication/welding is done elsewhere to exacting spec. I want the bike to be as if Kawasaki reissued a retro Z Fighter, a tastefully updated Z for the 21st Century. Like the modern Ducati and Guzzi stuff.

Engine wise, I'm trying to find a GPZ750 engine and do the 810cc upgrade but I keep missing out on them, they are getting rare - loads in the USA, non here. Will be a 650/750 engine of some sort.


I will be looking to you all for help and advice on the way as I know little about these bikes.

+1

Dude screw building my own bike you took what I have had in my head for so loong !

Hey how much for the spoke wheels ???? Link???
Got to build one of these for shure, any chance I could talk you out of the plans for the triples. I would be down to buy a set if you can order or put me in tuch with who is making them for you.I might want some 7/8 bar clamps added to the top. I cant ride clip ons !

810, 6 speed would be sweet!

First allow me to say welcome to KZR.

Second, I am happy that you decided to build your vision from scratch. It would be a shame to dismantle such a complete, clean Z650. That is a lovely bike as is, and I would keep riding it like that.

Third, I like your vision for the new bike. Those hubs for the spoked wheels are brilliant! The black and gold is a very attractive combination IMO. Looks like you have a good start to a well thought project. Let me know if I can advise you, as I am almost at the completion of a similar build.

Questions:
Where are you located? Your project has a rather European influence to it, in my eyes.

Is the powder coated image of the swingarm a photoshop, or the real thing?

BTW we have a member who is building a CNC machined triple-clamp setup for use with GSXR 1000 forks. His user name is irishwill. It may be instructive to have a chat with him about your machine work.

@ ready2ryde1985
Thanks dude. The wheels are basically off the shelf SuperMoto wheels using Talon hubs, Excel Rims and stainless spokes. The spec I wanted with the twin disc / cush drive hubs are basically KTM 990 wheels. You can get any wheel builder or supplier to build them using the above components. You can even get them on eBay ready made.

@ Testarossa
Yes, I'm in London England - home of the fast bike lol! We get about 2 weeks of sun and there are speed cameras so it's motorycling's natural environment. I will look up irishwill and will definitely be onto you lot for help. The swingarm was photoshopped - I like to mock up as much as I can to make sure it's all looking sweet. You are right about keeping my original Z F4 standard - means I can go Lawson green on this new one!

I love the tough minimal way the Scandanvians do it. These guys are awesome: www.wrenchmonkees.com

Thats a great vision for your bike :woohoo: As testarossa mentioned, member irishwill has designed and machined gullwing/offset triple clamps to accept later model gsxr1000 forks

kzrider.com/index.php?option=com_kunena&...limitstart=60#388442

Thanks dude - I had a look. My yokes are being machined by a small firm that supplies some parts for custom builder here in the UK and even MotoGP teams.

You can see some of his work here:

www.streetfighterpartsuk.co.uk/Custom_parts/Custom_top_yokes



+++++++
WHEELS

As above, I've ordered my wheels. The front is for a KTM Twin Disc 990. The wheel hub width from disc rotor face to face is 104mm.

Can anyone tell me if this is the same disc spacing / hub width as a regular modern sports bike wheel?

Basically, my yokes are being made to the specs of a 2006 Ninja, which is where my forks came from. I just need to know if my radial callipers will be way off - or at least within range of the discs via a few spacers. Apparently upto 9mm spacing is okay.

Otherwise, I will need to adjust the yoke width...?

Ratch, my 2004 zx-10r hub measures 130mm. It has perfectly flat brake rotors. The front hub from a 1995 GSXR 750 that is used in my project bike is 92mm wide with brake rotors that are dished. The dish puts the inside face of the rotors about 128.5mm apart. I would suspect that some combination of parts could be made to work. Another member, dutchz had custom machined brake rotor center sections or carriers made up. I bet your machine shop could handle the task if you don't find a stock rotor that will work.

It seems to me that the decision to go with a mono-shock or dual rear end is a biggie. The mono setup has some distinct advantages, but those Ohlins shocks you have are very nice. I guess if you decide to run a mono-shock you could always sell the Ohlins and more than pay for the new parts.

I have spent a few hours drooling over the wrenchmonkees handiwork. Initially I was going to mimic their creations, but my exposure to this site steered me to building a bike that is more "finished" in appearance.

Here's a link to dutchz's build where he had the carriers machined: kzrider.com/index.php?option=com_kunena&...it=20&limitstart=200

Cheers for that. I forgot about offset disc rotors. Hopefully something will be available off the shelf - either an offset rotor or spacers. I'm going to clamp up the forks to the wheel when it arrives and see where I am. Then either adjust the yoke width or deal with it at the wheel end depending on how far I am out.

Regarding monoshock, I'm going to stay twin Z style on this one. Not for simplicity sake, I just think it's an important retro feature, plus I already have the Ohlins ready. The next one will be Mono for sure. :evil:

What I am doing though is having 2 tanks, tails and side pods painted. One in Lawson Green race colours and the other in Black/Gold. That way I can swap those bits out if I feel like a change - 2 bikes for the price of 1!

royalratch wrote:

Cheers for that. I forgot about offset disc rotors. Hopefully something will be available off the shelf - either an offset rotor or spacers. I'm going to clamp up the forks to the wheel when it arrives and see where I am. Then either adjust the yoke width or deal with it at the wheel end depending on how far I am out.

Regarding monoshock, I'm going to stay twin Z style on this one. Not for simplicity sake, I just think it's an important retro feature, plus I already have the Ohlins ready. The next one will be Mono for sure. :evil:

What I am doing though is having 2 tanks, tails and side pods painted. One in Lawson Green race colours and the other in Black/Gold. That way I can swap those bits out if I feel like a change - 2 bikes for the price of 1!

Agreed, I would have a hard time letting go of a pair of Ohlins. They will definantly compliment the look of your bike, and I hear that they function quite well.

Good plan with the transformer bodywork.

Hi all.

Want to get the wheels on the bike ASAP to get alignment sorted early. I want the bike to handle as close to standard or better. Standard Z650 wheels are 18" on the rear and I think a 19" or 20" front.

I need some tips on tyre profile basically.

I like the meat of a 150mm / 60 on the rear (160 is too much I think and I'm sure will give clearance hassles).

And for the front, a 110/120 with 70 profile - this will give me some resemblance to original spec wheels but with a meatier rear and chunky front.

Does this all sound okay or a is going to ruin the ride/handling?

Small update.

Took a chance on another swingarm, a ZXR750 I think, that looked a little chunkier. Doesn't have eccentric adjusters but it's almost dead on for the original Z650 arm dimensions wise.

It's 1mm wider at the pivot so will slot right in with minimal trimming and only 2.5cm longer - but has a big tensioning slot which should bring that back in line.

Basically, weld on some shock mounts and machine off all the monoshock stuff and it's good to go - will save quite a bit of work/cash at the fabricators.





Was thinking to graft on the eccentric end clamps as I really liked the gold insert touch.