Carb Synch Information

PDF File with step by step instructions
STCarbSync.pdf

Hints from a few emails
Courtney Sullivan
You access the carb sync linkage screws with a long handled screwdriver, at least 12”. I use a sharp painted #2 Phillips, but the screws are also slotted for flat tip screwdrivers (I found the Phillips to be easier to find the screw and keep it in place as the screw is rotated).

You do not have to remove the fairing pockets as was previously indicated. Take off the seat, rear side panels under the seat, fake gas tank, and maintenance side covers. Shine a flashlight from the side maintenance cover into the engine over the valve cover and locate the carb sync linkage screws, two on the right and one on the left. The heads face up, and there is a brass spring beneath the head and the linkage plate that holds the setting.

Insert the screwdriver from above, sliding down along the outside of the air filter housing and between the breather hose, just to the rear of their front to back midpoint, with the screwdriver tip angled slightly forward. Look at the screws from the side as you fish the screwdriver tip down to get it onto the screw top; I hold a small flashlight in my teeth when by myself.

Once you figure out where to insert the screwdriver to get a straight shot at the screws it’s quite repeatable; you do wind up coming at the screw tops from above and to the rear of them, maybe at a 25 or 30 angle.

The screw on the right side adjusts one cylinder, #2 I think, and #4 is fixed and you adjust 1, 2 and 3 to it (or #2 is fixed, and 1, 3 and 4 sync to it; don’t remember so RTFB 2x and watch you gauges as you make changes).

Vacuum lines
The left side and just behind/to the inside of the valve cover, cyl 2 and 4, come from together at a “T” connecter, with the middle of the “T” then feeding the PAIR valves. Pull the “T”, and run 2 and 4 to your gauges; I just cap off the PAIR valve while doing the sync. #1 has a stub hose capped off above it (and behind the valve cover). #3’s hose runs to the fuel valve; I “Y” into it a few inches in front of the valve. 3/8” windshield hose connectors fit the stock vacuum lines just right and can be had at most auto supply shops.

So connecting the gauges to 2, 4 and 1 means your reaching across the top of the valve cover to hook up, and it’s damn hot when you go to disconnect after your done. Not to mention my big hands and fingers don’t work great reaching to hook up to the stubby stock vacuum lines. So I took a bunch of 3/8” ID vacuum hose and extended 2, 4, 1, and the PAIR valve to just ahead of the fuel filter.  Now when I want to do a carb sync I can hook up the gauges from by the right side of the real fuel tank/by the fuel filter (1, 2 and 4 being extended, and #3 on the “Y” just ahead of the fuel cut off diaphragm).

Doing adjustments
Take your time, and move the screws individually, not more than 1/8 turn at a time.

Pull the screwdriver up off the screw (it’s weight will affect the setting), blip the throttle and let the gauge settle back between adjustments. Tedious, but satisfying when done well.

Will England
You must have at least one 3/16" Tee connector, and 3 or 4 inches of 3/16" hose for the fuel petcock. (#3 cylinder)

The screwdriver only needs to be about 9" long. Worked fine.

From start to finish, including a trip to the parts store and a fussy 4 year old, I took 2 hours.