insured

Overbearing Aprilia
I have an Aprilia that is eating main
bearings. It’s an RS125 race replica
with 15k on the clock and generally
in top condition. My local dealer (not
an official Aprilia one) replaced them,
but they went again 200 miles later.
The dealer denied responsibility for
the problem and said I must have run
it out of oil or have been thrashing it
beyond what should be expected of
it. He did offer to do the job again for
the cost of the labour, but it didn’t
look like rocket science so I had time
off work to do it myself.
My friend and I replaced them
without too much hassle. The bike
ran fine but within 300 miles they
went again.
I always use fully synthetic twostroke
oil, good quality parts from a
proper bearing supplier and don’t
consider myself a throttle-happy
boy racer. I have run out of ideas
and my bike is currently laid up in
pieces because I don’t want, and
can’t afford, to make the same
mistake again.
Andy Mackin, Leicester
I’ve come across this one before.
Have you got the old parts to hand?
If so check the numbers on the side
of the bearing casing, along with the
four-digit number used to identify
the bearing itself (there is a letter
and a digit to show the clearance
within the bearing). This is critical for
particular machines; most Japanese
models run C3 bearings while
Aprilias using the Rotax engine like
yours must have a C4 clearance
bearing (allowing for a greater
expansion of the bearing due to heat
build up). This C4 bearing will not be
a commonly stocked item unless the
dealer or supplier normally works on
Rotax engines. I strongly suspect this
is the cause of the problem. If you
run a C3 bearing in the Aprilia it will
overheat and not last very long at all.
Suck, squeeze,
bang, no
My Honda SXR50 scooter suddenly
stopped and wouldn’t start again, I put a
new spark plug in and I have checked
the carb. It is clean and petrol is getting
in it, yet it still won't start. I took the
head off to check the piston and that
seems OK. I’ve checked for loose wires
etc, but it still refuses to start, I don't
know what else to do.
Rick Swindail, New Romney
One must always start at the beginning
and stick rigidly to the procedure until a
fault is found. You have already begun
this process but do not give me vital
information needed to trace the fault.
You say you have a spark, but what
colour is it? A good spark is a blue one,
ideally fat and vibrant. Secondly, where
is it happening? The timing may well be
out, so you will need a strobe light to
ascertain this. With these two
components in place, is the plug getting
wet with fuel? You can bypass the carb
by dripping a small amount of petrol
directly down the plughole to see if the
bike will fire up, albeit for a short time.
Is the plug getting wet when you try to
start it? You can have too much fuel in a
two-stroke engine and this will flood the
bottom end preventing the plug from
igniting the mixture correctly?
The next thing to check is the
compression. It’s OK having a look at the
top of the piston but unless this has a
hole in it you’re not looking far enough
down. It’s the rings that do the work in
that department so the barrel will have to
come off, or you can simply get the
compression checked. Any well-equipped
dealer will have a tester, and while I
wouldn’t expect the loan of it, they may
help out in some way. If this isn’t an
option, they are not expensive to buy.
Another forking problem
Is it possible to rebuild the front forks of my Piaggio Skipper? If so, where can I get
the parts?
Dean Stanyer, Trent Vale, Stoke on Trent
It is possible to rebuild most Piaggio forks, although there may be problems due to
corroded bolts etc, which makes disassembly very difficult. Once apart any Piaggio
dealer will be able to source the correct parts for you and may even have them in
stock. Make sure the bike is firmly held off the ground before you begin and try to
get hold of a manual so you can make sure you have the correct tools etc. Haynes
produce a book that covers your model in great detail.
Bromley city rollers
I own a Peugeot Speedfight 2 100cc. It’s
standard, no modifications and pretty
nippy, I can easily get 65mph out of it.
When I pull away I am getting a
drumming noise and sometimes it
struggles. It makes a vibrating noise up
to 30mph but past that it clears itself
and picks up speed very quickly.
I’ve phoned around a few shops they
reckon it could be the rollers. Can you
confirm this before I spend the money
out? I don’t want to pay out and find out
this is not the problem.
Phil Bateman, Bromley
Ghost in the machine?
Sounds very much like the rollers.
They are quite fragile and often
overlooked during regular servicing
and maintenance. Over time they
develop flat spots and eventually begin
to stick in one position. This causes
the belt to flap about and will result in
noise and vibration. They’re not
expensive to replace and while you are
in there you can replace the belt as this
sounds as if it has gone through the
mill a little bit. Also have a good clean
in and around the pulley area. Make
sure you get the correct weight rollers
as you may end up with a completely
different feeling machine.
My Piaggio BV200 starter engages when battery is connected in any ignition switch
or cut-off switch position. Even with ignition key removed.
Brian Cope, Pitman, New Jersey, USA
For this to happen there must be a
direct supply of voltage from the battery
live to the starter motor. I would check
the wire you are connecting to the
live/positive terminal isn’t the wire that
should be bolted to the starter solenoid
(they have the same size connector and
can easily be mistaken). I suspect that
you have no electrics when the ignition
is switched on either, as the red wire
that normally carries the voltage from
the battery isn’t connected correctly.
NOVEMBER 05 87