The carbs on these bikes can be a nightmare of rather obscure problems. One of them can be the cause of sticking carbs.

The synchronising brackets between the carbs are somewhat primitive. They do the job but could have been a better design.

I have found that some bending of the synch brackets needs to be done quite regularly on the units I've had in for rebuild.

But before you go attacking the carbs with big screwdrivers, since the spindles are made of brass and easily bent, let's try something to prove whether it's these brackets causing the stickiness or not.

Take off the chrome support plates. Disconnect the operating arms from the #4 and #3 carb.

Now try moving the lever on the #4 cab and see if there is any stickiness. If so, now undo and remove the synch adjuster. Check that both #2 and #4 carb are free to move, as it just might be that the stickiness is in the carb itself.

If both carbs are free at ths point, then you need to tweak the adjuster. Without refitting the sych screw, put the two parts of the adjuster together and eyeball the threaded hole through the slotted bracket. It will be apparent where the adjustment need to be.

Carefully!!! ease whichever bracket needs to be moved. It will only be a fractional movement in most cases. If it's not, then there is something more seriously wrong that needs to be investigatd.

Re-assemble the synch adjuster fairly loosely.

Repeat for the #1 and #3 carbs. Re-attach the operating arms and now take the big spring off the quadrant.

Follow the instructions here exactly to get the synch right:  http://www.wingovations.com/synchronisi ... 4590612876

Now put the big spring back on.

The 75 and some early 76 carbs did not have the return spring on the spindle of the #3 and #4, so everything needs to be very free on these if they are not going to stick.