How to drain the float bowls: Difference between revisions

6. Locate the brass screw under the bottom of the carb

So, you might ask "Why would you ''want'' to drain the carb float bowls?" It's a good idea to drain the carbs for long term storage (winterizing). It's also the first step if you're going to be removing the carbs for cleaning, but you'd also need to drain them as part of troubleshooting a non-running or poorly running bike... typically a rather ''sudden'' change in running condition, usually right after filling up with gas. This is normally water in the gas, which sinks to the lowest spot possible ~ the carbs.  

First off, the bike under dissection here is a Bandit 400. While not a 250, the work is the same, things look very much the same, and you'd get the same results (meaning this is something that is bike/manufacturer independent... the only requirement is that there are carbs).  

Tools needed (in this case) are a Phillips #2 screwdriver, a glass jar, and a hose/funnel. The 250 would need a 3mm allen instead of a phillips #2 screwdriver.  

The kind of shiny strip in this photo is just a channel of tin-foil used to direct the gas into the glass jar. Normal procedure uses some hose, but you can make do with what you have, should all your hose have been discarded in a recent move and you don't feel like taking a trip to an auto parts store. Another option is to cut a pop/soda/Coke can in half with a Ginsu knife and place it directly under the drain. Anyway, you just open (counter clockwise, lefty loosey) the drain screw, and fuel will drain out the nipple. You DO want to make sure that the tank petcock is turned off (if there is an off), clamped, or the vacuum system is working, or else you'll drain fuel from the tank, through the carbs, till the tank is empty. Pretty simple:  

Here's the jar of gas... yes, 10 oz. came out of the carbs (Note: 4-carb system - YMMV). It's that dark green because the previous owner didn't drain them and the gas sat in the carbs long enough that the corroding brass jets turned the gas this dark green. Not a carb-cleaning to look forward to.  

And finally, some clean water was added to the gas so you can see the separation. Normally, when you get water in the gas at a station, it's this dark, dirty, murky, nasty looking water... very much NOT clean like this. But if you have any water in the float bowls, it can cause poor running or no running at all.  

After you're done, to refill the carbs, just turn the petcock to PRI or prime (if you have it) or ON and crank the engine for a while. If you're just cranking the engine, it'll take several seconds (feels like eternity) for the fuel to drain into the float bowls and get to the level where it can be drawn into the engine.