DIRTBIKE

THE BACK END | LONG TERMERS

sit higher in the stroke and use that plushness
at the top of the stroke to absorb the sharp
choppy bumps.
Unfortunately, when measuring static sag on
the stock suspension my riding weight made
the bike sit lower in the stroke. This caused it
to feel harsh in the mid-part of the action.
No matter how slow or fast I was going on
the RMX450Z I couldn’t shake that harsh
feeling in the front-end. It absorbed the little
stuff like a lounge chair but the impact of the
square-edged rubbish went straight up my
forearms and gave me bad arm pump.
I also struggled with the standard shock
spring on erosion mound jumps. I easily
bottomed the shock when landing and the
rebound was too slow.
To resolve these issues, Ex-Factory Mechanic
Jay Foreman from All Pro Racing and RG3
Suspension, near Newcastle, NSW, rebuilt the
fork and shock. I’d already spoken to Jay about
the problems I was having and he had the
perfect remedy (see sidebar on the right). Jay
had the work done in a few hours and I was on
my way back to Melbourne to go riding.
I picked a test track we use regularly in the

Bunyip State Forest for my first ride with the

modified suspension. Instantly I noticed the

improved performance in the initial part of the

stroke. Preventing the bike from sitting too

low in the stroke helped with tree roots and

downhill breaking bumps. The heavier fork

springs prevented the front-end from diving

under braking when trying to tip into corners.

While the fork was an improvement, I found

the shock modifications more noticeable. It

absorbed the bumps without bouncing around

like a poorly built trailer. I still managed to

bottom the shock on one big over-jump but the

regular trail junk now went unnoticed.

It’s amazing how much of a difference a

reasonably priced suspension job can make. I

found the RMX450Z heavy and cumbersome in

the corners because the standard setup was too

slow and soft.

However, with the motocross kit fitted, the

bike feels like it skips over the bumps rather

than ploughs through them. It feels better

balanced and more aggressive.

In other news, I’ve made some changes to

the throttle pull and the seat, but more on that

next time. Editor Mitch Lees

Main: Valving and rods ready to go in the fork legs

ALL PRO RACING

RG3 WORKS MAGIC

We focused mainly on revalving the fork and

shock. It’s a complex job, we have to change the

compression, mid-valve and rebound on the fork.

We’re trying to introduce a plushness to it while

helping the bike sit up more in the stroke.

It’s very similar to what we did with the

Factory Suzuki motocross bikes. Suzuki have

been running the 47mm Showa motocross fork

for a while so we’re pretty comfortable with it.

The shock needed more plushness and we

achieved this by holding it up a bit and helping it

sit higher. We modified the valving and replaced

the shock spring with the heavier RM-Z450 one.

If you’re a 70kg guy the stock spring will be fine,

but you will still need to re-valve it.

Putting the heavier springs in the fork allows

us to soften up the valving. We can rely more

heavily (pardon the pun) on the springs to hold

the bike up, rather than the valving which means

we can go softer on the valving.

This allows us to use a plusher setting and get

the full travel of the fork legs. We also increased

the shim stack in the fork and shock to give it a

more progressive feel.

A standard fork can tend to sit in the hard

part of the valving. We want it to use the entire

travel. I think Suzuki has gone with the softer

spring in the RMX450Z, as opposed to the

RM-Z450, because that is the normal thinking

when you are building an enduro bike. Every

manufacturer does this.

The fork in the RMX450Z is very adaptable. It

can be setup for just about anybody and is a very

forgiving fork. You can race it or trailride, but for

now we’ve set it up for a trailrider.

It can be tricky to find a set up for off-road

riding because the terrain is always changing.

Jay Foreman

WITH THE MOTOCROSS KIT

FITTED TO THE RMX450Z, THE

BIKE FEELS LIKE IT SKIPS OVER

THE BUMPS RATHER THAN

PLOUGHS THROUGH THEM

TOTAL HOURS 19

MODS THIS MONTH

Suspension

MODS NEXT MONTH

Seat hump, throttle

RMX COST

RRP: $12,490 + ORC

Warranty: Six months parts

Distributor: Suzuki Australia,

(03) 9931 0500

HANDY TIP

When removing the shock from your RMX450Z

or RM-Z450, you can pull it out the right side,

rather than out the top. To get the shock out I

removed the seat, undid the top subframe bolt,

loosened the bottom subframe bolts and pulled

the subframe back from the frame. This meant I

also had to detach the airboot. I then pulled the

shock straight out the top. Wrong move. There is

a better way!

By simply removing the muffl er and sideplate

the shock will pull straight out the right side

of the bike. If only I had known this, because

reattaching the airboot was a pain in the arse.

140 | APRIL 2016 http://www.adbmag.com.au