Help! My 600 feels heavier than America's debt!

[ducatilover]

Hey guys, my ZZR600 is turning like an absolute pig, far worse than standard and it's dropped 20+kg off original weight.
I'm thinking my USD conversion has thrown the geometry out somewhat.
Could somebody please tell me:
Length between front axle and the lower clamp
If the axle is offset forward/rearwards?
If anyone has a ZZXR400/600 can they do those measurements?
If anyone is clever with set-ups, what would make the front end feel horribly heavy and slow to turn on the road?

The bike:
ZZR600d chassis
ZXR400H1 forks, 10W fluid (Fuchs), 6th position in on the damping, 1 whole turn on pre-load
Standard ZZR600d rear shock, good condition, damps fairly well, about half way on the pre-load adjustment.
Pilot powers, 120/70 and 160/60 at 32 and 36 psi respectively.
Sits around 175kg dry, standard is quoted at 195kg.



Anyone able to shed light on how I've destroyed my handling gets an internet beer! Cheers.

I will drop the forks in the yokes a bit and see what happens, but it feels seriously heavy at open road speeds and the forks are even with the top clamp.

[GrayWolf]

Hmmmm OK... dont know if you 'just' replaced the forks, or the complete triple tree as well, soooo

IF triple clamps/stem replaced..... Are head bearings correct size? Over tightened? are the shoulder measurements identical between the stems for clearance, positioning? IF you replaced the stem, there could be some very subtle differences for diameters and heights...
If you measured the headstock against the OEM one... is the distance from stem to fork holes the same? the clamps may not only spread the forks wider, but MAY physically position them fore or aft by a few mm of the original clamps position?? that few mm if forwards WILL slow down the flickability a little.

If they are upside down forks, did the donor bike have the same rake angles? I have noticed a lot of upside down sprotbike forks have a very steep angle... if your forks are at a more 'relaxed' angle... is it causing 'stiction' on the sliders?
Are you 100% sure the 'new' forks are straight?
Are the new forks 'slightly longer'?? Slightly shorter?
is the front wheel 'identical' between the two bikes? it may look identical, but again a mm here or there, especialy if the forks were wider/narrower spacing could leave the forks being 'pinched or spread' to accommodate the wheel.
Leading/centre/trailing axle?? again will affect trail/angle...........

[ducatilover]

New triples, old forks were right way up (not when I finished with them...)
The top triple sits s tiny bit lower (3 or 4mm) than original
Correct size bearings, steering is mint at low speeds and no notching or anything when stationary.

Wheel has had the spacer and speedo drive machined down, fits spot on.
Distance from stem to fork leg is 2mm less on each side from memory (I think there was a total of 4mm machined off spacer/speedo drive)

Fork length is something I am unsure of, because the old forks looked like this:

265291265292
That's why I've asked for someone to check for me if anyone else has one floating around, same with the axle, this one's centered and I'm fairly sure the original was too.

New forks are not bent.
Wheel is a ZZR600 wheel, and as said, spacers made to fit it.

Low speed riding is okay, tipping in at 80k+ it feels as fat and heavy as fuck. Heavier than it previously did.

As for fork stiction, they work well at low speeds and the damping rate is okay, sure don't feel slow to react over bumps

[ducatilover]

The forks that are on it are off set a fair bit further forward, I think that answers my question, I'm struggling to find the original rake/trail specs.

[HenryDorsetCase]

It might be the offset of the forks ("forward" relative to the centreline of the headstock.): it it is longer then even if everything else is the same it would slow the steering down.

There is a recent Performance Bikes article that discusses this (with pictueres) because they are racing a Triumph 955i and the replaced the whole front end with one from a CBR900RR. It quickly got quite technical but the factoid (opinionoid?) above is something I remember from that article. I dont know if I still have the magazine: will check.

or you could buy Tony Foale's book:

http://www.tonyfoale.com/book.htm

or look at his website: He knows things about stuff.

[Fast Eddie]

:corn:

no doubt new triples and forks will have changed something :D

lets see how you fix it..

dropping forks will make its steer quicker eh? got a steering damper on it?

[tigertim20]

New triples, old forks were right way up (not when I finished with them...)
The top triple sits s tiny bit lower (3 or 4mm) than original
Correct size bearings, steering is mint at low speeds and no notching or anything when stationary.

Wheel has had the spacer and speedo drive machined down, fits spot on.
Distance from stem to fork leg is 2mm less on each side from memory (I think there was a total of 4mm machined off spacer/speedo drive)

Fork length is something I am unsure of, because the old forks looked like this:

265291265292
That's why I've asked for someone to check for me if anyone else has one floating around, same with the axle, this one's centered and I'm fairly sure the original was too.

New forks are not bent.
Wheel is a ZZR600 wheel, and as said, spacers made to fit it.

Low speed riding is okay, tipping in at 80k+ it feels as fat and heavy as fuck. Heavier than it previously did.

As for fork stiction, they work well at low speeds and the damping rate is okay, sure don't feel slow to react over bumps
firstly, are you sure its not just from being used to riding geoff the last wee while? not riding your bike for ages can mess with your perception of weight and power.

did you check your tyre pressures as well?

other than that, Id say that you are on the right track with getting the axle to triple length confirmed - but its going to take you all of ten minutes to drop the front 10mm, and take it out and see if its better or worse, youve changed a hell of a lot, so getting measurements from a stock bike probably wont help much.

also consider what weight you have removed from where, and how much this affects the weight distribution, rather than just overall weight, and how much weight is currently being help up by the 400 forks, compared to how much weight was on them on their original bike.

[Fast Eddie]

they are racing a Triumph 955i and the replaced the whole front end with one from a CBR900RR.

did they? what year? wtf for haha.. are they any good? I'd be keen on readin that

[carburator]

check your new triple trees against your old ones for the difference in offsets to the bearing head.
low speed it would be fine, high speed you have less leverage ratio against the effects of centralfugla force
of the said turning moment of the front wheel ( feels like its in cement )

http://community.jpcycles.com/articles/tech-articles/pages/triple-trees-and-frame-geometry.aspx

[GrayWolf]

The forks that are on it are off set a fair bit further forward, I think that answers my question, I'm struggling to find the original rake/trail specs.

2 possibilities I can see.....

1) the forks are set further forwards.. physicaly 'lengthening' the bike between axles.... longer bike, more stable but slower steering.

2) they are longer.. this has lifted the bike physicaly at the front if you have put then in 'flush'.... try dropping the clamps 4-5mm and see if anything changes for a kick off.

[HenryDorsetCase]

did they? what year? wtf for haha.. are they any good? I'd be keen on readin that


they started with a stock 955i a year or so ago and put it on a hell of a diet, upped the performance significantly, and raced it in one class last year. This year they are racing it in a thing called Golden Era Superbikes which is unrestricted (vs I think thunderbikes which was power to weight ratio restricted),... let me see what I can come up with.

[ducatilover]

It might be the offset of the forks ("forward" relative to the centreline of the headstock.): it it is longer then even if everything else is the same it would slow the steering down.

There is a recent Performance Bikes article that discusses this (with pictueres) because they are racing a Triumph 955i and the replaced the whole front end with one from a CBR900RR. It quickly got quite technical but the factoid (opinionoid?) above is something I remember from that article. I dont know if I still have the magazine: will check.

or you could buy Tony Foale's book:

http://www.tonyfoale.com/book.htm

or look at his website: He knows things about stuff.
Will have to have a light read methinks :D thanks


:corn:

no doubt new triples and forks will have changed something :D

lets see how you fix it..

dropping forks will make its steer quicker eh? got a steering damper on it?
No steering damper, except for when my wrist hits the frame in a tank slapper...


firstly, are you sure its not just from being used to riding geoff the last wee while? not riding your bike for ages can mess with your perception of weight and power.

did you check your tyre pressures as well? That popped in to my head, but it's not that, it is properly heavy in the steering at speed.
Tyre pressures were double checked, 32 front, 36 rear.


other than that, Id say that you are on the right track with getting the axle to triple length confirmed - but its going to take you all of ten minutes to drop the front 10mm, and take it out and see if its better or worse, youve changed a hell of a lot, so getting measurements from a stock bike probably wont help much.

also consider what weight you have removed from where, and how much this affects the weight distribution, rather than just overall weight, and how much weight is currently being help up by the 400 forks, compared to how much weight was on them on their original bike. Will drop the front and see what it's like
The 600 is 175kg dry at the moment, ZXR400 claimed at 163kg from memory.
The dry distribution was pretty even too.


check your new triple trees against your old ones for the difference in offsets to the bearing head.
low speed it would be fine, high speed you have less leverage ratio against the effects of centralfugla force
of the said turning moment of the front wheel ( feels like its in cement )

http://community.jpcycles.com/articles/tech-articles/pages/triple-trees-and-frame-geometry.aspx
Old triples were kind of snapped and the scrap man ate them. Looking at pics though, it seems the original ZZR triples offset the forks closer to being inline with the stem
Actually, I might have kept a snapped triple for teh lulz, will have a look soon

That makes sense to me


2 possibilities I can see.....

1) the forks are set further forwards.. physicaly 'lengthening' the bike between axles.... longer bike, more stable but slower steering.

2) they are longer.. this has lifted the bike physicaly at the front if you have put then in 'flush'.... try dropping the clamps 4-5mm and see if anything changes for a kick off.

Will be giving it a go, but I reckon it's how far forward they are.

[Ocean1]

The forks that are on it are off set a fair bit further forward, I think that answers my question, I'm struggling to find the original rake/trail specs.

Too much trail.

If you project a line down the centre of the steering head to where it intersects the road then trail is the distance from that to the centre of your theoretical tyre contact point.

Changes to the angle between the fork clamp centre and the steering head angle will change the trail, so will changes to axle offset in the forks. So will changes to the distance between the fork clamp centreline and the headset centreline.

Too much trail makes it difficult to turn the steering, not enough makes it twitchy.

Edit: if it's a huge change your fukct. You'll get some improvement pulling the forks up the clamps, try 5mm, check clearances and go ride. Try some more...

[nzspokes]

Was this the same frame that you crashed on? Head stock in frame bent?

[ducatilover]

Was this the same frame that you crashed on? Head stock in frame bent?
Nope, different frame, a straight one :D
The old 400 frame was twisted and cracked in a few places

Too much trail.

If you project a line down the centre of the steering head to where it intersects the road then trail is the distance from that to the centre of your theoretical tyre contact point.

Changes to the angle between the fork clamp centre and the steering head angle will change the trail, so will changes to axle offset in the forks. So will changes to the distance between the fork clamp centreline and the headset centreline.

Too much trail makes it difficult to turn the steering, not enough makes it twitchy.

Edit: if it's a huge change your fukct. You'll get some improvement pulling the forks up the clamps, try 5mm, check clearances and go ride. Try some more...

Just found the broken original triple, the new forks are about 7mm further forward.
Have pulled the forks up 10mm, will give it a go if it's dry tomorrow.
ZXR400 trail is 24 degrees/85mm rake/trail
ZZR600 is 24.5 degrees/97mm rake/trail.
I'm running a 120/70 vs the ZXR400 running a 120/60

[ducatilover]

Here we go


According to online calculators I'm running about 108mm/4.28in of trail.
Oooooopsie! There's my problem.

The specs incase anyone wants to check and make my trail look better

24.5deg steering angle
Tyre diameter 600mm
Triple clamp offset 25mm
Fork length to axle 730mm
Triple tree rake 0deg

[ducatilover]

Yup, so it definitely has 108-109mm of trail, dropping the forks 10mm isn't going to move the trail back much at all, I want similar to what it had, or just slightly less.
So I have a plan.

Give up and ride the fuckin' thing.

[Ocean1]

Yup, so it definitely has 108-109mm of trail, dropping the forks 10mm isn't going to move the trail back much at all, I want similar to what it had, or just slightly less.
So I have a plan.

Give up and ride the fuckin' thing.

It's 11-12mm more than std, which is admittedly on the high side to start with.

Dropping the nose 10mm won't get that 11mm back, but it, (and p'raps cranking the rear preload up a turn or two) might just make it feel a bit less like a very heavy non-turning sled thing.

[ducatilover]

It's 11-12mm more than std, which is admittedly on the high side to start with.

Dropping the nose 10mm won't get that 11mm back, but it, (and p'raps cranking the rear preload up a turn or two) might just make it feel a bit less like a very heavy non-turning sled thing.

I'll see what it's like with the 10mm drop in the front, hopefully the small reduction in rake and steeper steering angle will help 'er out.
The rear pre-load is a bitch to turn up, but can be done.

I've turned a fairly beige handling bike in to a tank, with less weight and more power :lol: Only way I can see getting the steering back to happy is doing the logical thing.
ZX6R/636 front end with custom triples...mmmmmm :drool:

[tigertim20]

they started with a stock 955i a year or so ago and put it on a hell of a diet, upped the performance significantly, and raced it in one class last year. This year they are racing it in a thing called Golden Era Superbikes which is unrestricted (vs I think thunderbikes which was power to weight ratio restricted),... let me see what I can come up with.


Yup, so it definitely has 108-109mm of trail, dropping the forks 10mm isn't going to move the trail back much at all, I want similar to what it had, or just slightly less.
So I have a plan.

Give up and ride the fuckin' thing.

how about a custom triple?
few lads on here have the tools, and might like the challenge for a fellow kb tinkerer

[ducatilover]

how about a custom triple?
few lads on here have the tools, and might like the challenge for a fellow kb tinkerer

With ZXR forks? Nah, fuck that. I'll get some proper bling forks, radial brakes and then upgrade the swingarm/shock. That'll make double sure that I ruin the geometry

[bogan]

if you take 2.5 degrees of the rake it'll be down to 94mm trail. Which only means dropping the front by around 68mm :eek: so 0.22mm trail reduction for every mm you raise the forks through the triples.

[ducatilover]

if you take 2.5 degrees of the rake it'll be down to 94mm trail. Which only means dropping the front by around 68mm :eek: so 0.22mm trail reduction for every mm you raise the forks through the triples.

:2thumbsup Choice, thanks bro. So, I could put the 19 inch rim off the GN on the front and strap the forks down? After putting my bottle jack in the back instead of the old fashioned spring/shock.

[madmartin]

: After putting my bottle jack in the back instead of the old fashioned spring/shock.

from memory the shock in my ol ZZR600 was comparable to a bottle jack anyway...
sadly not too many wreckers have busted these bikes-well they hadn't when i had one anyway. If you can locate the guy up in auckland i sold my rolling chassis to you'd prob find yourself a good front end... he only wanted the vin plate. His name was Dean Bradbury, not sure if he's on KB or not

[ducatilover]

from memory the shock in my ol ZZR600 was comparable to a bottle jack anyway...
sadly not too many wreckers have busted these bikes-well they hadn't when i had one anyway. If you can locate the guy up in auckland i sold my rolling chassis to you'd prob find yourself a good front end... he only wanted the vin plate. His name was Dean Bradbury, not sure if he's on KB or not

The rear shock will be replaced when I get a different swingarm, have a set up in mind currently and it's not a Kawasaki unit :cool: The front end will not be going back to ZZR parts, the ZXR forks damp much better than the ZZR ones, the ZXR USD forks will be ditched down the road for newer USDs that have radial mount brakes :headbang:

The rear shock in this is bloody good as far as ZZR units go, but, that doesn't mean much. :msn-wink:

Have you got any ZZR bits floating around? I like spare parts

[madmartin]

i think i've got a weld repaired RH engine cover somewhere but would have to check, everything else got the big heave-ho years ago chap

265307

[ducatilover]

I've got a spare set of covers, so no need to check :msn-wink:
It's a shame you haven't got the motor floating around, yours was an E model and they have nicer internals (ZX636 pistons fit right on to those rods...)

[madmartin]

The engine was why i got rid of it, there were no valves left, was over $1500 in bits to get her going again :(

It had a kinda "colorful" life, being stacked into a river very early in it's life. Then it was a race bike for several years (hence me having to rebuild the gearbox twice)

Have some fond memories of my ol "krack-a-sickie" tho, she was cool

[ducatilover]

The engine was why i got rid of it, there were no valves left, was over $1500 in bits to get her going again :(

It had a kinda "colorful" life, being stacked into a river very early in it's life. Then it was a race bike for several years (hence me having to rebuild the gearbox twice)

Have some fond memories of my ol "krack-a-sickie" tho, she was cool

I'm wanting an E model bottom end to put my D model head/cams on for my turbo build
E model = better range of aftermarket bits because the rods/journals/wrist pins are the same as later ZX6 engines and the D model has a reasonable head for turbo set ups and the least extreme cams at 280deg@.50 lift

Mine's had a colourful life and I've only had it 13-14 months I think... :(

[madmartin]

sounds like you've done your homework, must be kinda tricky to work out the numbers with all those rocks in your head banging about tho! :bleh:

[ducatilover]

sounds like you've done your homework, must be kinda tricky to work out the numbers with all those rocks in your head banging about tho! :bleh:

:( You have no idea mate

[madmartin]

just checked car jam, 93TWS is no longer assigned to a vehicle, so there's an E1 engine sitting out there somewhere with a good bottom end & pistons

[ducatilover]

just checked car jam, 93TWS is no longer assigned to a vehicle, so there's an E1 engine sitting out there somewhere with a good bottom end & pistons
I'd love to find one, but I'd love to find the money :lol:

[ducatilover]

I made a mistake in my figures.
The clamp offset is 35mm

So, with a 600mm tyre
24.5 degree rake
0 degree angle clamp
730mm forks
35mm clamp offset

My trail is 98.2

Now I am confused.

I'm off to measure again...
Edited with correct measurements.

That's the same as a Hayabusa... oh God.

[GrayWolf]

I made a mistake in my figures.
The clamp offset is 35mm

So, with a 600mm tyre
24.5 degree rake
0 degree angle clamp
730mm forks
35mm clamp offset

My trail is 98.2

Now I am confused.

I'm off to measure again...
Edited with correct measurements.

That's the same as a Hayabusa... oh God.

LMFAO so you have a bike that handles like a ZZR1100??? :clap::2thumbsup:lol:

[ducatilover]

LMFAO so you have a bike that handles like a ZZR1100??? :clap::2thumbsup:lol:

Not any more, dropped the forks in increments (must have looked hilarious) during a ride today. They're down 13mm and it handles very nicely, turns fast and not head shakey over bumps.
The road I went down is a bumpy fucker, so thought it'd be a great way to start.
Might dial in a wee more front-preload and see what happens too, dives a little under brakes.

[nzspokes]

Not any more, dropped the forks in increments (must have looked hilarious) during a ride today. They're down 13mm and it handles very nicely, turns fast and not head shakey over bumps.
The road I went down is a bumpy fucker, so thought it'd be a great way to start.
Might dial in a wee more front-preload and see what happens too, dives a little under brakes.

Preload may not help that. But great its riding better.

[Ocean1]

Might dial in a wee more front-preload and see what happens too, dives a little under brakes.

Check the fork oil.

If it's allready clean and the right level then add 10mm.

[ducatilover]

Check the fork oil.

If it's allready clean and the right level then add 10mm.
Fuchs 10w filled to 430ml, factory sez "5W 424+-5ml"
Maybe I could just turn the damping up...:facepalm: I forget I have these things.

Preload may not help that. But great its riding better.

Oh well, I'm pretty happy with it... biggest understatement you've ever read, I'm fucking chuuuuuuuffffed.

[FROSTY]

Have you thought of using the old racer trick and steepening the steering head a couple of degrees?
I'm thinking that pushing forks up through triples might reduce ground clearance

[hayd3n]

cbr1000rr rear swinger should suffice :P:bleh:

[ducatilover]

Have you thought of using the old racer trick and steepening the steering head a couple of degrees?
I'm thinking that pushing forks up through triples might reduce ground clearance
I'm pretty happy with how it's turning now and it's only a 13mm drop. The headers haven't hit the ground and it's been down some properly rough roads :D
I don't ride fast enough to drag pegs, so that isn't a huge issue.

cbr1000rr rear swinger should suffice :P:bleh:

I measured the 600 up and the CBR swinger is going to be a c*nt to fit and too long :mad: Gutted, because they're a grouse looking unit

[Fast Eddie]

Check the fork oil.

If it's allready clean and the right level then add 10mm.

I was told to avoid adding more and more oil to stiffen it up..

:D how it running bro? done any monos yet.. gwarrn. a bit of hair from the dog that bit ya, at least do a burnout for the camera.

p.s. is there anywhere legal to do burnouts. ie. will I get in trouble if I do doughnuts in my garage?

[Fast Eddie]

I'm pretty happy with how it's turning now and it's only a 13mm drop. The headers haven't hit the ground and it's been down some properly rough roads :D
I don't ride fast enough to drag pegs, so that isn't a huge issue.


I measured the 600 up and the CBR swinger is going to be a c*nt to fit and too long :mad: Gutted, because they're a grouse looking unit

nice, im a peg or exhaust dragger me self.. think thats just cause im fat and sack the bike out tho.

vfr400 single side unit.. I like them, did one on the cbr600f I had.. always a fuckn mission to do any swingarm conversion but worth it for something that looks beast.

yea the 1000rr prolink units look chunky, i like em too. with a big fat rim.

[ducatilover]

I was told to avoid adding more and more oil to stiffen it up..

:D how it running bro? done any monos yet.. gwarrn. a bit of hair from the dog that bit ya, at least do a burnout for the camera.

p.s. is there anywhere legal to do burnouts. ie. will I get in trouble if I do doughnuts in my garage?
It's running mint :D No skids or wheelies yet, just some closed private road testing to see if anything fell off.
Riding without seat foam = pain.

nice, im a peg or exhaust dragger me self.. think thats just cause im fat and sack the bike out tho.

vfr400 single side unit.. I like them, did one on the cbr600f I had.. always a fuckn mission to do any swingarm conversion but worth it for something that looks beast.

yea the 1000rr prolink units look chunky, i like em too. with a big fat rim.
I'm a bit of a wuss ((% of the time, got a pace I enjoy and I stick to it, although seeing what parts of the GN can scrape is fun.

Is the NC2/30 SSSA running an offset shock? I know the Honda Bros units do and I'm pretty sure the early VFR750 did.
I'd love one with a VFR800 5 spoke rim, or the bad arse 18 inch units that my Bros650 had (not the normal egg beater ones, some nom nom white three spokes)

[tigertim20]

I was told to avoid adding more and more oil to stiffen it up..

:D how it running bro? done any monos yet.. gwarrn. a bit of hair from the dog that bit ya, at least do a burnout for the camera.

p.s. is there anywhere legal to do burnouts. ie. will I get in trouble if I do doughnuts in my garage?

the speedway in green island do burnout nights every now and then.
in your garage, with the doors shit and locked - youre legal. its private property and no longer a public road as locked doors prohibit access by the public.

The same applies to the living room if you have wooden floors!

[Ocean1]

I was told to avoid adding more and more oil to stiffen it up..


It doesn't stiffen it up, it just reduces the air volume more as it gets close to bottoming, progressively increasing the spring rate. Can make a fair bit of difference, but it does pay to look for model-specific advice before going too far. And then, nothing beats having the right springs in in the first place...

[ducatilover]

It doesn't stiffen it up, it just reduces the air volume more as it gets close to bottoming, progressively increasing the spring rate. Can make a fair bit of difference, but it does pay to look for model-specific advice before going too far. And then, nothing beats having the right springs in in the first place...

I'm happy with how it is currently, doesn't get upset by shit heap roads. It's set up a wee bit soft because the majority of the roads I ride are extreme and have poo surfaces. And I like being comfy.

I've got a plan for the swing arm conversion. :2thumbsup