ZXR 400 Suspension
Martin Harrison
I have a ZXR 400 and am having troubles with the suspension.
Ever since I got it I havent been to happy with the handlig on bumpy bends -
it usualy tries to throw me off.
e.g. A bike ahead takes bend at 60MPH no probs, I take it at 50MPH, the back
wheel hits a bump and I wobble across the road.
So I decided to wind the rear spring preload off a bit, this made it take
bumps a bit better but it wouldnt then go round corners!!
So I wound it back to where it was before and carried on further. Now it
takes the bumps much better (without bottoming out 2 times on speed ramps).
The remaining problem is that the front end feels decidedly 'odd', and
occasionaly has a mind of its own.
I contacted the bike shop today who informed me of which nut is which
adjustments and the factory settings (I haven't got a manual!), and it
appears that they were set to the factory default before I fiddled with
them.
So is it advisable to alter setting from factory default?
If so should how far should I wind the preload on the front to compensate
for what ive done at the back?
Or is it that my rear spring has just become a little lazy and I need to
visit the bank manager to buy a new one?
Any help would be appreciated......before It throws me off in a bad
temper........
Martin Harrison
Mike Fisher
Martin Harrison <ne...@magic.force9.Remove-this.co.uk> wrote in message
news:5ipT2.4534$14.1703@wards...
<Deep breath>
It's all about keeping a balance.
Basically, within ground clearance limits, the higher the back, and the
lower the front, the better / faster the bike will turn in. There is a trade
off with stability, but we'll deal with that in a moment.
The first thing to do, is to set everything back to factory settings, and
find a piece of road that will make the bike misbehave.
Ride it several times. In both directions. Get off, have a smoke, and think
about what it's doing.
a) Is it running wide ?
OK, then you need to increase the height of the rear suspension mid corner.
Doing so decreases the effective rake, and will help you steer it. Try
reducing the front preload, or increasing the rear - or both in combination.
b) Is it pogo-ing over bumps ?
Increase the rebound damping at the end that is bouncing.
c) Is it unstable under power on the way out ?
The rear isn't "squatting" enough under power. Reduce rear bump damping, or
soften the spring / preload. Beware ! Too much squat can lead to loss of
traction under power. Early ZX-9's are testament to this.
d) Is it vague, hard to hold a line ?
The suspension may be generally too soft, and taking too long to "settle
down". Try increasing the rebound damping, one click at a time, at both
ends.
e) Is it unstable under braking on the way into corners ?
Too much weight transfer to the front. Try either increasing the rear
rebound damping, or increasing the front spring preload.
f) Do bumps unduly affect the steering ?
Too much compression damping at the front. This is usually unadjustable on
most bikes. The closest you can get is to try and reduce the front preload a
little. It might help.
Repeat the process until you feel happy.
The whole point of this post, is to help you understand that suspension is
not simple. The whole subject is very complex, and extremely subjective.
More importantly - it's quite possible (nay, likely) that worn components
are causing your problem.
What state are the following in:
Head bearings ?
Tyres ?
Tyre pressures ?
Suspension linkages ?
Fork oil ?
Rear shock ?
Wheel bearings ?
Any one of the above components being shagged will make a far bigger
difference than any of the tweaks I mentioned.
Contact one of the acknowledged experts. They'll be able to help you far
more than I or anyone else in the group can.
I suggest Ron Williams at Maxton Engineering as a good starting point.
Try 01928 740531, or visit them at http://www.maxton.demon.co.uk/
</deep breath - phew !>
HTH.
Mike.
Neil Murray
> <Deep breath>
<snip the rest>
Bollocks.
The fact is that the ZXR400 has crap suspension.
It needs re-engineering to work. Contact Maxton, as you said.
--
Neil Jawa Combo 750S S GT750 CB400F CD175
The Older Gentleman
BOF #30 GAGARPHOF#30 GHPOTHUF#1
http://www.btinternet.com/~Chateau.Murray/homepage2.html
Mike Fisher
Neil Murray <Chateau...@btinternet.com> wrote in message
news:1dqmq7z.1pe...@host5-99-51-224.btinternet.com...
Concise as always.
> The fact is that the ZXR400 has crap suspension.
>
> It needs re-engineering to work. Contact Maxton, as you said.
That was the whole point of the post...
Mike Fisher
Mike Fisher <wh...@cableinet.co.uk> wrote in message
news:7flfdn$nc9$1...@news1.cableinet.co.uk...
>
> Neil Murray <Chateau...@btinternet.com> wrote in message
> news:1dqmq7z.1pe...@host5-99-51-224.btinternet.com...
> > Mike Fisher <wh...@cableinet.co.uk> wrote:
> >
> > > <Deep breath>
> >
> > <snip the rest>
> >
> > Bollocks.
>
> Concise as always.
>
Although, I'd be worried to find there was *no* truth in what I said.
Opinions ?
Martin Harrison
Mike Fisher wrote in message <7flbqm$h2d$1...@news1.cableinet.co.uk>...
>
>
><Deep breath>
>
>It's all about keeping a balance.
>
>Basically, within ground clearance limits, the higher the back, and the
>lower the front, the better / faster the bike will turn in. There is a
trade
>off with stability, but we'll deal with that in a moment.
>
>The first thing to do, is to set everything back to factory settings, and
>find a piece of road that will make the bike misbehave.
Well its been at those settings for the last 7 months, and its only now that
ive deced to tackle the problem, also that the roads are drying out a bit
now and th problem is showing up!
>
>Ride it several times. In both directions. Get off, have a smoke, and think
>about what it's doing.
>
>a) Is it running wide ?
>
only if I get to scared to lean it enough!
>b) Is it pogo-ing over bumps ?
maybe at the back end
>
>Increase the rebound damping at the end that is bouncing.
>
>c) Is it unstable under power on the way out ?
wouldnt say so
>
>d) Is it vague, hard to hold a line ?
>
Not on bends but sometimes on strighter roads although that maybe just me!
>The suspension may be generally too soft, and taking too long to "settle
>down". Try increasing the rebound damping, one click at a time, at both
>ends.
>
>e) Is it unstable under braking on the way into corners ?
yeh!! - scares me as well! - hence ive come to the conclusion of tampering
with the front suspension!
>
>Too much weight transfer to the front. Try either increasing the rear
>rebound damping, or increasing the front spring preload.
sort of what i guessed
>
>f) Do bumps unduly affect the steering ?
humm.......no (its me that effects th steering after ive hit a bump and its
wobbled or bounced!)
>
>Repeat the process until you feel happy.
thats the next 2 years taken up then!
>
>
>The whole point of this post, is to help you understand that suspension is
>not simple. The whole subject is very complex, and extremely subjective.
Which is why ive left it 7 months before deciding it really does need
something done about it!
>
>More importantly - it's quite possible (nay, likely) that worn components
>are causing your problem.
now i start to get paranoid!
>
>What state are the following in:
>
>Head bearings ?
dunno - probably ok
>Tyres ?
front - new 7 months ago, back about 3 months old and not compleatly
scrubbed in on edges as everytime i try it hits a bump!
>Tyre pressures ?
front = 35psi ish
back was at 42 - now reduced to 40 in combination with fiddeling with
preload.
>Suspension linkages ?
there underneth the bike, got some mud on, and ive got nothing to support
the bike while I look in close detail but i would think their ok.
>Fork oil ?
ermmm....dunno - it doesnt squeck, creack, or feel stiff and moves freely
(to freely!)
>Rear shock ?
well...th dampner is ok...question is what state the spring is in
>Wheel bearings ?
no funny noises down there
>
>Contact one of the acknowledged experts. They'll be able to help you far
>more than I or anyone else in the group can.
>
>I suggest Ron Williams at Maxton Engineering as a good starting point.
>
>Try 01928 740531, or visit them at http://www.maxton.demon.co.uk/
>
ill try that....
Martin Harrison
Neil Murray wrote in message
<1dqmq7z.1pe...@host5-99-51-224.btinternet.com>...
id sort of herd that kawasaki had gone through a crap suspension phase - and
knowing my luck thats just what i got!
>
>It needs re-engineering to work. Contact Maxton, as you said.
or as some suggest - a new bike!
AWegg8888
does kick about a bit, but that's part of the fun..Back the rear preload off as
much as you can/dare. NWS do rear suspension replacement linkages that help a
bit, or get the rear shock rebuilt by Maxton...however the rear wheel generally
follows the front one..so don't worry unduely about it. At the front end,
soften off the preload, change the fork oil - go for a top quality synthetic
and as light as you dare - I'm running 5-weight at the moment which has needed
a bit more prelaod to compensate...
Another contact you can try is MH suspension in Wiltshire. They will do you a
personal set up sheet for 3 quid detailing the *ideal* settings for your
weight, whether you take a pillion etc.
As the man said before, its a question of balance. You're never gonna get a
ZXR to feel anything other than skittish and a bit harsh - it *is* a race bike
with lights after all - but you can make it a bit more bearable. If you want
something plusher, try a ZX6R. The bottom line however is that the ZXR
suspension does work and it handles.
Any bike that can go into the Mountain at Cadwell Park in torrential rain at
10mph
too much and get me round under control with the front wheel nodding (that'll
be the edge of the grip envelope then) is OK by me...
Bastard Bear
>
> Mike Fisher <wh...@cableinet.co.uk> wrote in message
> news:7flfdn$nc9$1...@news1.cableinet.co.uk...
> >
> > Neil Murray <Chateau...@btinternet.com> wrote in message
> > news:1dqmq7z.1pe...@host5-99-51-224.btinternet.com...
> > >
> > > > <Deep breath>
> > >
> > > <snip the rest>
> > >
> > > Bollocks.
> >
> >
>
> Although, I'd be worried to find there was *no* truth in what I said.
>
> Opinions ?
Regularly.
--
Regards,
Bastard Bear
These are my own opinions, and not necessarily those of all Bears
TART#1 UKRMHRC#8 "Still pissed after all these hours"