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Carburetor Draining Procedure ( ST1100 ) *

Started by KoTAOW, November 06, 2014, 06:47:16 PM

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Submitted by Adam Frymoyer, STOC #949


Carburetor Draining Procedure ( ST1100 )

For quite some time, I’ve been meaning to post a carb draining procedure for the ST1100. This year I finally took the time to take some pictures while I drain the carbs for winter storage. I strongly recommend carb draining for LONG TERM storage. My bike sits for 5 to 6 months, pending on winter conditions. It is also a good maintenance practice to drain out any contaminants (if any) of the float bowls into a clean container. If you see any crud while draining, there is a potential problem in the fuel system that needs to be looked into. Most guy’s don’t drain the carbs. They choose their favorite fuel stabilizer, add it to the tank, fill the tank, and walk away.... Most of them get away with it for a long time, but how many times a year do we help someone through a carb rebuild caused by sitting / storage? As always, this is just my opinion and the way I do it. Please follow the service manual for the proper way to work on your bike.

I first start by removing some of the body panels needed to gain access to the float bowl drain screws. I have to remove the (optional) fairing extensions / deflectors, center maintenance cover and the panel plugs.

I always push out the panel plugs very carefully from the inside, out. Always a risk of damaging these cheesy plastic plugs by prying them out with a screw driver.

Now that everything is out of the way, I go to the recycle bin and get out a clean container to drain the fuel into. The carburetor’s drain hose is down at the bottom of the bike just behind the side stand pivot and shifter. This particular jar I used was able to be wedged up in the body panels and stayed firmly put. Even full of gas.

I have a long flathead screwdriver to get down into the bowl screws. This particular driver had to be ground down on the sides to reach into the recessed bowl body to get at the screw head. It’s a cheapo Harbor Freight driver that only gets used once a year for this job.

I suppose you could start were ever you want, but I do the easy side first. I always start off with doing #2 (left front) carb first, then work my way back and around to the other side. I tried to get the best pictures I could, but those screws are WAY down in there. Get the brightest flashlight you own to look in there!

I hold the flashlight inside the bike while looking down through the plug hole. You’ll have to bend down the black rubber insulator mat with the driver, but the screw is easily viewed and accessed. I open it up a couple of turns and let it drain for a couple of minutes. I also leave the driver in the screw head while draining.

Now that #2 is drained, I tighten up the screw snug and move back to #4. Same procedure for #4, however you will need to use the cut-out in the fairing for driver clearance.

Getting more gas !

Now that #2 & #4 are drained, I move over to the right side of the bike and do #1 & #3. This side is tricky due to the engine breather hose that is routed right between the two carbs. Also, this side is a lot tighter for screwdriver clearance between the valve cover and the synchronization screws. Don’t disturb the synchro screws while getting the driver down in there!

As I said before, it’s tricky getting around the breather hose. I use a bungee cord to pull the hose out of the way “gently”. If the hose was pulled on too hard, it may pull itself out of the air cleaner assy. I took the best pictures I could of how I do it.

Here is a picture of the breather hose. Also notice how close the synchro screws are.

Unfortunately, the bungee has to be used for clearance on both right side carbs. Pull forward for #1 carb. Pull back for #3.

In this pic, you’ll notice the bungee hook around the breather hose as I drain #3 carb.

Now that the carbs are drained, I can re-assemble the body work. I always put the panel plugs back in first.

That’s it. I’m all done. Bike is back together and ready to be put away for the winter. It only takes me around a half hour to do the whole carb draining job from start to finish.

Here is the jar full of gas showing how much will come out. I peeled off the wrapper for better visibility. I’m also happy that there’s no junk in my carbs!


Thank You again for your contribution Adam Frymoyer, STOC #949