Z800 Cafe Chopper Fighter thing...

[Ginger Bear]

I'd keep 'em gold. Works well with the hubs & Ohlins.

[Jay1969]

Liking the tank colour a lot, suits the bike well - I'd go with the black/black forks deffo.

[j.wilson]

black/black best.
gold looks like .....a tarts handbag!

[Royalratch]

Lol.

The thing with the gold is its been done quite a lot. But my main issue is it doesn't look very unique or 'custom' - looks like I just lifted any modern GSX / ZX10 front end and plonked it on.

I was into it big bit now I see the engine and frame together - I might have to go black fork down!

[KWACKERZ1]

black black.

[chrisu]

gotta go black.................

[Royalratch]

Forks off for rebuild / Nitriding.

There is an option to have new springs in there - maybe heavier duty to deal with the extra weight. I'm sure this is worth doing for the money and ride.

I weigh 80KG. The bike weighs more than the bike the forks came from (2006 ZX6R Ninja) but less than the original bike - Z650.

I guess I should weight the bike during a rough assembly then + my weight and see what the suspension people suggest?

Or will the difference be negligible?

[j.wilson]

There are some good guys at RaceLab- worth talking to them.

http://www.racelab.co.uk/home/home.php

Its an interesting issue you have.

The DRY weight of the ZX6R was about 180kg but this figure is a bit of a con as this is without oil and battery etc- the CURB weight was more like 200kg.

Your Z650 is probably going to tip the scales at about the same weight. My 1400cc Z650 weights in at 208Kg wet and its got more stuff on it than yours- (fuel pump ecu etc, etc). So I don't think the weight difference is going to be great enough to be significant.

However there are a couple of things that you may want to consider and this is where RaceLab can help- first is spring rate and the second is damping.

The static weight distribution of you special will be different to the ZX6R and so will the weight transfer on braking, finally the un-sprung weight of the Z650 front end may also be different.

The cumulative effects these differences may require you to make changes to the suspension (by changing parts) however you will not know this till the bike is finished. My advice is to go with what you have till its finished and then take it to a specialist for set-up (Spring rates, preload, ride height, compression and rebound damping).

There are lots of issues with handling and I don't think your spring rate is the primary one. Also be very aware of the tyre profiles you are choosing.

There are many different types and some will be designed for very different lean angles and stability than you are ever going to achieve. You don't want a superbike tyre- but one that gives good stability and traction at normal lean angles.

I use knobbly tyres on my bike (all be they radials) and they provide HUGE grip- more than I've ever experienced on a Z before- these modern tyres are designed for the weight and lean angles of my type of bike. However a set of R1 tyres would probably feel quite unstable (they have sharper middle radius and flatter sides for extra grip at large lean angles).

Your suspension is fine as it is, get the bike going- expect to have to change something that will effect the handling- and once you are happy take it to a good shop to finally set it up.

Your doing a good job, don't let every detail worry you.

[LondonZ1]

I think your bike looks great, very unusual and really cool. The brown colour sounds horrible but works very well. Personally I would go for black forks. If you want some more colour, I think traditional yellow Ohlins springs at the rear would work work well. I ordered black springs for my Zed special and yellow ones turned up but they looked so good I kept them. But obviously it's all down to personal taste.

Regarding the suspension, I agree with j.wilson. Finish the bike as it as and then take it to a specialist. My Zed has Ohlins at both ends which were designed for a CB1300. My bike is probably lighter than the CB but I'm going to ask Harris to sort out the spring rates and damping when it's back from Debbens.

[j.wilson]

I'd guess that the ZX6R suspension may actually be too hard for your bike. It will have been designed to accommodate much higher peak loads so the spring rate will be greater than you need- so may feel a tad too hard on your bike (bangs over bumps a bit) and the rake of the ZX6 is 23.5 degrees and yours is 27 degrees - that just makes the problem worse.

That's just a guess of mine- hopefully it will put you off making changes today- wait till you know what the problems actually are.

[Royalratch]

Cheers lads.

I'm in no way going to ride this bike to any limits but whilst the forks are in bits it would be the time to do it.

But I'll get riding first then ask the pros for suggestions. I suggested custom spring because its a reasonably priced tweak for a lot of return. Custom valving is OTT. Compression / rebound does need to be set up as although I know how it works I often cannot tell the difference after a fettle.

[j.wilson]

You're doing a good job. How's the project feeling at the moment?
Its been rolling a long time- are you still OK with it all?

[Royalratch]

Feel like I'm on the couch.

Its taking too long but that's my fault for being OCD about it.

But that's fine. Do it right now so I have the bike in my head and no regrets.

I also hate relying on others for everything - even to turn some basic spacers etc.

I'm in the lookout for a desktop cnc lathe!

[j.wilson]

Good to hear, projects that take a long time can be an emotional roller coaster ride. Especially when there is a setback.

You’re doing a great job and the bike will be great as a result of your efforts. Keep it up.

I know relying on others is a pain for many reasons- and certainly it’s great to learn to do as much as you can yourself.
I would question going to a CNC lathe. I should start with saying I’m not an expert on this – its just some ideas you might want to toy with- chuck out if you don’t agree.

Hmm, CNC mills work both X and Y axis simultaneously to produce curves, Z axis as well for 3d shapes, and even 4 and 5 axis for complex shapes.

Think about the things you want to machine to determine how many axis you want to control.

My experience of turning is that it is not often that I want to turn curves. I usually want to cut simple shapes. Sometimes I want to cut a combination of simple shapes, but rarely complex curves. So, given these simple cuts the simultaneous control of the several axis on the lathe is not such a useful facility.

Automatic feed on an axis may be all you need. Given the cost of CNC you can get a much better manual lathe for the price of a CNC lathe- and by better I mean more accurate, more rigid and with a greater capacity.

I’ve found I got the biggest advantage from being able to do additional processes to the turned part.

Adding a milling function to the lathe (in another machine or in the same machine) adds a huge number of things that you can make. I have a combo machine, and I’ve had to modify it quite a bit and buy accessories for it too but it has paid for itself many times over.

I still lament not having CNC control- but really only in the milling function.

I’d say go for a bigger manual lathe and a milling machine too.

[Royalratch]

I only want cnc because I'm a bit if a tech geek - dont need it. But I do want a lathe and milling machine but not huge beasts. Just something to cut the odd spacer or modify a part.