Specifications

Post 2: TOOLS
Screwdrivers.
Jets with slotted heads are easily deformed, and problems can be avoided by grinding
screwdrivers to achieve a tight, no-slop fit in main and pilot jets. Screwdrivers and bits
with tapered blades tend to apply pressure only at the upper edges of the slot; hollow
ground screwdrivers make contact equally from top to bottom, and are less likely to
damage jets. If your carbs have float bowl plugs, main jets can be installed and
removed without removing float bowls. For BS series, use a 1/4" drive bit, ground as
above, and turn down the shank until it clears. Turn it with a 1/4" box end wrench, or
5twins' weapon of choice, a Sears finger bit driver (http://tinyurl.com/y9xar5). 5twins
also notes that Wiha 2" metric power bits in 4 mm (pilots), 6.5 mm (small round mains)
and (possibly, this is untried) 8 mm. (large round mains) are a good fit; see
www.wihatools.com For VM carbs, use a 6 mm. 1/4" drive deep socket and hex drive
adaptor for the main jets, turning with a 1/4" box end wrench. Set the screwdrivers and
bits aside for use only in carb work.
Caliper or Steel Rule.
A caliper is useful for measuring float height (see Section II. or Section III). The end of
the depth probe can be set on the carb body while the corner of the shank is sighted on
the float top. Some prefer to sight the float top with a small steel rule.
Fuel Level Sight Tube.
A direct reading of fuel level can be taken with a sight tube. Find a rubber plug to fit the
plug port in the bottom of the float bowl. Drill it and fit it with a hard plastic tube or hose
barb,and attach about 8" of clear plastic hose. Some BS-series carbs are fitted with a
drain valve in the float bowl, opened by a screw, with a nipple for a drain tube, to which
a sight tube can be attached. See Section II. for use.
Manometer (Synchronizer).
XS650's after 1976 are fitted with vacuum ports in the carb bodies, vacuum line barbs in
the mounting boots, or both. Synchronizers can be connected to either location (see
Section II. or III.)
Inexpensive dial gauges should be avoided. Mercury manometers ("mercury sticks") are
commercially available, but mercury is highly toxic and the device is easily broken.
Morgan makes the Carbtune synchronizer, employing steel rods, but it is limited in
accuracy and expensive.
A very accurate and durable tool can be made with a yardstick, 10 ft. of 3/16" clear
plastic tubing, a few ounces of automatic transmission fluid (some folks prefer 2-stroke
oil), and a pair of pilot jets (the long-pattern jets for Mikuni flat slide carbs, sizes 15 to