Z800 Cafe Chopper Fighter thing...

[LondonZ1]

CB1300 Ohlins are 310mm eye to eye uncompressed. There are lots of other ones in the 320-330mm range from memory so you should be able to find something off the shelf. Call Oliver Pearson at Harris and he will be able to find the best match for you. It's partly a cosmetic choice, I don't like bikes that sit too high at the rear but each to his own.

[martinz1000r]

you could reach out to Mike Capon at M shock. He'll build custom shocks for you and is reasonable on price and very high quality. He built the shock on my Martin.

http://www.shock-factory.co.uk/m-shocks-home.html

[Royalratch]

Thanks lads.

@LondonZ1 - yes a 320mm shock would be perfect but settled in at 300mm under rider weight and more maxed out I'd get issues with my front forks bring so short plus exhaust clearance. My slightly higher rear will be compensated for by a set of Zed105s clever internal for spacers.

Net result is a chassis that's almost level in laden but with much needed clearance between Rear wheel and frame and exhaust collector and ground. I have no idea how chain line will be affected.

If it's all wrong then the same era Suzuki GS1000 Ohlins at 331mm sound spot on - but may need custom springs.

Exhaust clearance will be the deciding factor.

[j.wilson]

Good work Royalratch, getting everything to work together properly is a real challenge- but its worth it in the end.

I agree with LondonZ1: "I don't like bikes that sit too high at the rear but each to his own."

There are good functional engineering reasons to properly set the frame horizontal, it wasn't made like that by accident.

There's not much mechanical sympathy shown by changing it simply to overcome another problem.

You end up with a bike with two problems (or actually many more) - not no problems.

[Pigford]

If it's all wrong then the same era Suzuki GS1000 Ohlins at 331mm sound spot on - but may need custom springs.

NOTE: GS 1000 shocks have a forked fitting to suit the swingarm

[Royalratch]

Yeh the Clevis mount type - but if you;re ordering new you can spec eye-to-eye mounts = I think!

I'll take any S36P thats around 330mm unloaded.

About Spruing rates.

Z1/Z900 is 245KG Vs Z650 211KG. Not much in it?

At what point does weight difference require a sprint change?

[Royalratch]

Success.

Have ordered a set of these - aluminium bodied S36P but with a 10mm ride height adjuster and uncompressed length of 336mm. Slightly more than the standard version but still less than half the fully adjustable ones.



No clue how they are set for damping or sprung rate but the supplier knows what bike they're for and suggested them so hopefully it will be useable. All this effort is a little overkill for what is essentially a summer garage queen but doesn't mean it shouldn't all work properly.

[LondonZ1]

They look fab, good choice. Black springs or yellow? I ordered black, Ohlins supplied yellow but they looked 'right' so I kept them.

[Royalratch]

Black springs - They must be black!

They are also swapping out the springs to suit my 200KG estimated bike weight + my weight so are semi-custom and hopefully plug and play. They are alloy bodied so a little lighter than the standard ones too.

No idea what the damping characteristics are but I may need to get the forks re-spriung to match the rate at the rear and try to eliminate any rock'n'roll.

KZ650 Stock Weight = 211KG.
My Z800 = 200KG.
2006 ZX6R = 192KG Wet.

So not much in it. I'm 85KG so maybe the stock springs in the forks may be okay.

It will all get set up by a suspension pro when done - its important as I want it to ride properly and when I had my Speed Triple set up (new fork internals, new rear shock, custom fork springs and tuned damping all round) it really transformed the ride.

[Royalratch]

Hi all.

Been busy and and will show a nice update on what's been happening shortly.

Quick question tho - up until now I've not been into the idea of putting a front mudguard on at all. I like the raw clean 'chopperish' look.

But what are the real world implications? Bad idea? It will only ever be out on dry sunny days.

The other question is - I quite like the modern fenders, maybe trimmed down to be a bit shorter - but I know this is seen as not cool for a retro build. However, older fenders on USD modern front ends also don't look right.

Here's a mock up.

[Pigford]

No front muddy is a No-No All the dirt & any water will go all over your visor/face ........ and even if you plan to use it in the dry only, you'd be surprised how many "wet patches" you find

[Royalratch]

Well it seems everything is trying to stop me from finishing this thing for an August 1 MOT. I'm halfway through making the loom, fitting throttle cables and generally getting it to a stage where carbs can be flitted and tuned.

But!

I have always been annoyed at the quality of the swingarm mods and that the pivot bolt is exceptionally tight. So taking it all apart has revealed that the ape who set it up for me has in fact just fitted some massive brass reducer sleeves to run directly on the pivot bolt - no bearings AT ALL.

It's with a top notch machinist now who is quoting £400 min to bore and fit a new sleeve with a proper set of bearings and a titanium pivot bolt - apparently the whole pivot area has been gorilla'ed and needs some serious reworking.

So I'm now 99% certain I'm going for a custom swingarm. Have pretty much settled on a metmachex - a clean chunky box section, unbraced and with twin shock mounts obviously.

My question would be does anyone know any other swingarm makers that build one for £600 max fitted?

Also, what should I consider in terms of mods regarding length and shock placement etc.

Thanks for hanging in there Z1OC - I know this must be getting boring...!

[garyd]

Have pretty much settled on a metmachex

Hav'nt they gone out of business?

2nd hand ones come up often enough & £150 should bag an unbraced one.

[garyd]

Apparently not!!

http://metmachex.net/swingarm-prices/


It was JMC I was thinking about.

[j.wilson]

Swing arm- I went 1.5" (38mm) longer on the swing arm, and that's fine even with my 1400- a bit of wheelie but nothing that slows you down.

The standard 650 swing arm is pretty short but makes the bike turn nicely, I suspect that you don't need to change the length much with your motor.

Don't be persuaded that it needs to be 2.5" longer- it don't.

The problem with the bigger swing arms is that they get quite fat near the pivot and start interfering with the chain (I mean it rattles on the metal) which is annoying. I've put plastic rub strips around mine, just to stop the worst of the rattle, but I will next go for the biggest front sprocket I can get to give me more clearance.

Some standard alloy arms from modern bikes are a pain in this regard because of the offset that the nearside of the arm has. In the end, I think its worth buying a few cheap ebay arms till you find something that when modded will fit nice.

I swapped out my needle rollers and fitted a bronze bush as the bearing surface was much larger. I had problem with a sub standard JMC arm which seemed to have a soft bearing tube that went oval. Ray Debben machined it away and fitted a new tube, bearings and all. No problem since.

I have been looking at swing arms, and pretty much all the alloy standard ones are actually heavier than the original z650 steel arm. The may be more rigid but they are heavier.

Of the standard ones, actually the steel bandit 600 is the lightest.

As for shocks, the biggest challenge is clearing the chain (having stepped it out round a wider tyre) and yet neatly meeting the top mounts. And of course, with thick box tube on the arm the shocks get even shorter as the mounts have to move up.

Don't be tempted to lean those shocks over too far, I moved my bottom shock mounts back as the swing arm got longer, but probably only went back 1".