DIRTBIKE

THE BACK END |USED BIKE

Suzuki’s first attempt at a 250cc

four-stroke motocrosser came as a

combined effort with Kawasaki in an

effort to cut development costs.

The RM-Z250 and KX250F were

identical, apart from the plastics. You

could actually change your Suzuki

into a Kawasaki and your Kawasaki

into a Suzuki if you wanted. The

motors were twin overhead cam units

with shim-and-bucket adjustment.

The motor was fed an air/fuel

mixture through a Keihen FCR

carburettor and kept cool through two

nicely sized radiators. After the RM-Z

came out, Suzuki announced a recall

to replace the spark arrestor in the

airbox and the hot-start plunger.

The plunger was replaced to

prevent water entering the carby and

potentially seizing the device. The

spark arrestor was replaced to try

to rectify a problem with the valves

wearing prematurely.

Suzuki gave all kinds of reasons for

the wear, such as incorrectly fitted air

filters and overheating, but I can tell

you the standard valves just weren’t

up to scratch.

A common fix was to fit stainless

steel valves and then replace the valve

springs with dual coils to compensate

for the heavier valves. This would

result in a slight drop in performance

but a much more durable engine.

The other, much more expensive,

option was to fit titanium valves and

copper beryllium valve seats. This

maintained valve train performance

and was much more durable.

The other RM-Z problem was that

when it came to changing the oil filter

you had to dump the coolant and

remove the water pump cover.

When looking at buying one of

these bikes second hand be sure to

check with the owner as to what type

of valves are in the head and how long

ago they were fitted.

Also check to see if the bike starts

and idles smoothly. A dead giveaway

of crook valves on these bikes is that

they are hard to start and will either

idle really high, hunt up and down or

not idle at all.

And as with any second-hand bike,

be sure to check all the suspension

linkages are moving freely, without

any excessive play or tightness, and

check to see the brakes work correctly

before test riding it.

These bikes performed well once

their problems were rectified. They

are very nimble to ride and were a

great race bike if looked after well.

Technical Editor Mat Boyd

NEW PRICE

2004 $9990

2005 $9990

2006 $9990

SECOND HAND

2004 $3800-$4600

2005 $4000-$4800

2006 $4200-$4900

All prices listed on this page

are fromThe Red Book

(redbook.com.au) and are

indicative market range only.

$3800

to

$4900

PRICE

GUIDE

JOINT VENTURE

MARKET

EQUIVALENTS

Honda CRF250R

$3000-$3900

Kawasaki KX250F

$2900-$3900

2004-06 SUZUKI RM-Z 250

Yamaha YZ250F

$3200-$4300

KTM 250SXF

$3600-$4300

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

BRAKES

The front brake is a single disc

with twin-piston fl oating caliper

while the rear has a single-piston

fl oating caliper.

FRAME

The frame had a sticker saying

‘Kawasaki Heavy Industries’.

WEIGHT

The RM-Z 250 comes in at a

dry weight of about 92.5kg.

VALVES

The valves were titanium coated

but once that coating had worn

through they wore rapidly.

SIDECOVER

Look for an aftermarket sidecase that has a seperate

cover for the oil fi lter, saving you from having to dump

the coolant every time you change the fi lter.