Here's a drawing showing the arrangement of the o-rings we'll be working with. In between each two carburetors are three aluminum pipes joining the carburetors' passages. Two of the three are fuel passages, while the third is an air passage. Note also in this picture the choke shaft and plates, which must be removed to do this job, the dust seals for the choke shaft, the bowl vent "T" at the upper left that you may chose to leave out if it is badly deteriorated, and finally, the small spring near the bottom of the picture, of which there are just two, one for each carb bank.

Start by making sure it's the o-rings that are the source of your leak. After removing the carburetors, mount them on the bench in their normal position and rig up a fuel supply. Now you can easily determine whether or not the bowls or the castings (o-rings) are leaking.

Once you're sure the passage o-rings are leaking, start by removing the choke plate screws. A good fitting #2 Phillips screwdriver is essential if you want to avoid tearing up the screws. In this example, a previous mechanic painted over the screw heads, probably because the screws had been removed before.

Using a #3 Phillips, remove the front, main, steady plate.

Then with the #2 Phillips again, remove the smaller rear steady.

Disconnect one of the linkage shock absorber mechanisms. A small 8mm socket works well here. Then carefully remove the ball joint from the mechanism, taking care to not crack the delicate aluminum part, or tear the rubber dust seal.

Disconnect the accelerator pump and gently separate the two carburetor banks.

Carefully remove the choke shafts. They're not very robust, so be gentle. Be sure to keep them separate, as they are not the same.

The o-rings we are replacing are not available from Honda separately. One of the better sources for these parts is TIMS. Ask for part number CRB 181.

Here we see the three pipes mentioned earlier. The ones closer to the float bowl are the fuel passages, one of which is an accelerator pump passage. The third one up near the carb top is the air passage for the air cut valve system.

After replacing each o-ring, smear a light coating of thin grease. Petroleum jelly is good. Electric connector grease is fine also.

Once all the o-rings are replaced, start reassembling each carb bank. Here we're pushing together carbs #1 and #2.

Perhaps the toughest part of this whole job is getting the throttle synchronzing linkage back together again properly. In this close-up, note the correct alignment of these parts. There are two washers. The small washer goes below the other carb's throttle arm, while the larger washer goes above it. Take care to get this arranged correctly. Here's a tip. The reason the washers are different sizes is to make it easier to work the carbs together. Start by engaging the larger washer with the second carburetor's throttle arm, wedging the washers apart as you wiggle the carbs together.

Once you have one carb bank assembled properly, bolt up its steady plate to prevent its working itself apart again.

Now reinstall the choke shaft, after greasing it lightly.

Starting with the accelerator pump rod, then the rear-most pipes, assemble the two banks together.

In this close-up, note that the accelerator pump passage pipe is the only one of the bunch (aside from the fuel inlet) that is not symmetrical. In fact, there is a line scribed by the factory on the right side of the pipe, showing which is the right side. Note also that the choke linkage is assembled above the accelerator pump passage pipe.

Now that you have all the carb castings connected, you'll want to prop up one side of the carbs to keep everything connected.

The air cut valve's air passage pipe goes in last. Note the reference notch that keeps the pipe at the correct angle.

Now that the two banks are completely together, join the two steady plates with the middle steady.

After all the carb rack fasteners are tightened, reinstall the choke plates. It's a good idea to use a mild Loctite solution on the screws. Honda's have a reputation for "swallowing" their choke plate screws.

Finally, before installing the carbs back on the bike, leak test them one more time. Could save you a lot of trouble should you have overlooked an o-ring or maybe pinched one.