Carb
Synchronization
Unlike many
other V-twin engines, the VStars are fed by dual carburetors. While
this setup does offer some advantages, it
requires
that the carburetors be kept in synch for most efficient operation.
This procedure will be all too familiar to us old gearheads who have
had to tune British sports cars or motorcycles. The process is not
difficult on the VStar, and should be done at Yamaha's recommended
intervals--every 4000 miles-- as well as at any time changes (such as
re-jetting) are made to the carburetors. You'll be amazed at how much
smoother your VStar will run after the carbs are synchronized.
The process
is not difficult, but you will need some basic hand tools and a
manometer or carb synch gauge. Gauges made for this purpose are
available from Dennis Kirk or other motorcycle supply vendors.
Another option is to make your own gauge; I made a gauge that worked
perfectly well using materials purchased at a local hardware store
for under $5.
1. When
building a homemade gauge, line restrictors are not necessary but
will help to smooth out your readings. Rather than buy restrictors, I
inserted an old main jet into each line--they fit perfectly in
3/16" hose.
2. I set
the idle high--about 1500 rpm to make adjustments, then back to 1000
rpm when I was done.
3. It is
very difficult to get a screwdriver on the head of the adjustment
screw, so I used a 7mm wrench instead.
4. Turn the
adjustment screw slowly--a small turn can make a big difference in synchronization.
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