need help Engine struggling in low RPM

[climbinfool]

I have a 98 Suzuki Bandit 600S. It was running ok, then got parked for a few months being started only occasionally. I recharged the battery and it would not start, just crank forever till the battery was drained. I pulled the plugs and they were very carbon fouled so I replaced them and changed the oil. The bike fired right up. Then it started puffing a good amount of white smoke and when I rode it, it would struggle and almost stall out until about 5000-6000 rpm, then it would take off. I noticed the fuel lever was set to RES, so I switched it to ON thinking maybe there was some crud or something in the bottom of the tank where the RES pulls from. When I switched it, it ran perfect for about 25 minutes then started doing the low rpm struggling again. Also, it appeared that some gas was leaking from around one of the carbs. What Kind of problem should I be looking for? Carb issue? clogged fuel line? vaccuum problem? I don't know what to look at.  Has anyone had similar issues or have suggestions? Thanks.

[pmackie]

Likely you need to remove the carbs and clean them, but you can try a couple of other things first...

1. Check, or likely replace your air filter.
2. Remove the tank, and drain all the fuel from it, best to remove the petcock from the tank and drain anything out. If you can, drain it into a glass jar that will let you look at what has accumulated in the tank.
3. Replace your in-line fuel filter, if one is installed.

At this point, if the bike is still not working well, you should remove and clean the carbs, but you could try using something like SEAFOAM first, if you want.

[climbinfool]

Thanks for the suggestions. I will give it a try. I was going to replace the air filter anyway, but I imagine it has more to do with the fuel. Now I wish I hadn't filled the tank. What is the safest way to drain the tank (It's full)? I have never done that before.

[rider123]

Sounds like bad gas to me. If you haven't put stabilizer in the tank than the gas is probably stale. Drain and replace or as you drive keep filling up. On reserve you are getting gas right from the bottom of the tank, right where any crap is. If you don't want to drain it just ride on the highway for a bit and keep filling up until its all gone. Gas goes bad fairly quickly so if your parking your bike for more than a month I would put stabilizer in the tank. Filling it up is actually a good thing because there is less of an air gap for condensation, but without stabilizer it will break down quickly.

Don't add any additives like sea foam until all that bad gas has run through your bike. The gas already has a hard time igniting, sea foam will make it worse. Ride for like an hour then top up the tank, etc. Even mixing some good gas with the bad will help alot. Use low octane until your sure the gas has gone through the bike as it's more burnable, then switch to whatever you use normally. AFTER you figure the bad gas is gone add some seafoam in the tank and go for a highway ride to really get the stuff flowing through the carbs. You'd be suprised how good it will run with a little sea foam and a good long highway jaunt. Because it's starting and running mostly you might not need to take apart the carbs at all try the easy/cheap fixes first.

What I do if I'm storing for the winter is fill the tank right up. Put the fuel stabilizer in (75ml per 20 litres) Run it around for 15 or 20 minutes to make sure that the stabilizer has hit the carbs. Store the bike and start it twice a month for 10 minutes to keep the fuel flowing and charge the battery. Springtime rolls around and it drives perfectly as it's been semi-running over the winter.

If you want to drain the tank, go buy a gerry can and some cheap 1/4 inch or 3/8th inch diameter tubing. Put the gerry can on the ground and suck on the tube until gas begins to flow on its own by gravity. You may get a mouthful of gas so be careful then drain the tank and fill back up with fresh gas. If you don't want to have gasoline hanging around you can put some of it in your car every once and a while as long as your at least 3/4 full it will be diluted by the good gas.

Or if you like take the tank off the bike and either stick a funnel and a gerry can under neath the spigot or get some tubing and attach it to the fuel petcock. Then switch the petcock to "prime" and the gas will flow right out.

[rider123]

I was going to add if you want when you have good gas in there you could try the "italian tune up" method of clearing the carbs. This is an old dell'orto carb trick as they would get condensation in the float bowls easily after parking for a while.

What you do is take off the seat and the document tray so you have access to the snorkle. Make sure the bike is warmed up. Rev the bike up to 5 or 6000 then as you let off the gas cover up the air intake with your hand until it's back down to idle. Do this a few times. It sounds crazy but it works. What it does is create a shitload of vaccuum that will suck up any light crud or water in the float bowls. That and some fresh gas and maybe a little sea foam in the tank I'll bet will fix it right up.

[climbinfool]

Interesting. Thanks a ton for the info. I'll post how it turns out.