[noche_caliente]

I saw this on another forum, and went to do a bit more exploring. It seems that the reason so many of us are having difficulty with our carb screws is because they aren't Phillips at all!

Is this the right time to mention JIS-spec screws and drivers?

In theory, all Japanese motorcycles use JIS-spec screws, rather than
SAE or generic metric screws. JIS-spec cross-head screws are
(apparently) marked with a single dot or an "x". So, what's the
difference between JIS-spec and the rest? In most cases, not much,
but if you've ever wondered why it is so easy to strip out the head on
a Honda cross-head screw (aka "Phillips", or more properly but still
wrong, "Japanese Phillips"), it is likely because you are using a
Phillips screwdriver on a JIS-spec screw...

As any astute reader of Wikipedia knows*, Phillips-head screws (and
drivers) were specifically designed to "cam out" when too much torque
was applied in either direction. That's bad enough (and one of the
reasons why "Pozidrive" screws and screwdrivers were invented), but
this tendency is exacerbated when the wrong driver is used and/or the
fastener in question is a bit stuck. JIS-spec screw heads are
shallower, which means that Phillips screwdrivers won't fully seat in
them (unless ground down a bit). In addition, the JIS-spec screw head
features a completely parallel cross, while the Phillips screwdriver
has a taper to its cross-point.

Most cross-head screws found on modern Hondas are button-head, which
can usually be removed with a Phillips driver, but I've found some
countersunk JIS-spec screws (albeit only on my NR rear wheel...) into
which no Phillips or Pozidrive screwdriver I've tried will even fit.
So, I've had to research JIS drivers and have found that they are
available (the RC helicopter boys seem too have the same problems with
JIS-spec fasteners) online if you know where to look, but that most
people and companies outside of Japan have absolutely no idea what
they are. Since I often buy stuff through Yahoo Japan Auctions, I
will probably score my set of JIS-spec drivers from there at some
point, as the ones exported into the USA don't seem to be of the
highest quality (and I have yet to find any being sold here in the
UK). Vessel and KTC seem to be the leading brands, though each have
drivers of varying quality. And I think there are only two common
sizes, unlike Phillips and Pozidrive, which are commonly available in
0, 1 and 2. HTH.

(* My way of stating that what follows sounds right but could be
complete bullshit.)

Ciao,

JZH
London, UK
www.vsource.org


On 6/3/08, Patrick Shelston wrote:
>
> The only thing I would mention is that the screws and bolts on the carbs are
> generally softer, so it is key to use good tools and the right sized screw
> drivers (snug fitting) to prevent stripping/breaking. I figured this out
> the hard way

from here: http://vfrworld.com/forums/vf-vfr-ma...s-drivers.html