[TomServo]

So i'm working on the bandit 400 I bought from arimichael and things are looking much better. New plug wires, plug boots, kreem'd the tank, bunch of stuff. Haven't done anything to the carbs yet and I think its time to cause there's a flat spot.. ok, dead spot really when I hit around 6-7k rpm in 6th gear. it'll accel up to about 65~70mph but give it more gas and nothing happens.. give it a little more gas and it starts to bog down a bit. let off the gas and it recovers and hold at about that speed. No I can get it a bit past that speed in 5th up to about 75 or so but it starts bogging down again. Only does this under a load.. you can rev as much as you want sitting in neutral. One other thing that might help is after you've been going for a couple of miles and come to a stop, the idle will drop to like 500 or so for a few seconds, then it raises back up to normal idle speed. Doesn't do it if you're just tooling around the hood, but get out on the main road and will do this.
Ok, so usual suspects? I don't know if the carbs have been synced but have the tool and will do that soon, but what else can cause this sort of behavior? Help

 

[doxiedog]

Carb time new mains and CHECK flowt level all the same. Then sync.
Are those CV carbs? If check diaframs for pin holes.

 

[Harsh]

A buddy of mine has a Bandit 600 and has a very similar problem. We synced the carbs but it didn't help at all. Eventually we are going to tear them down and completely rebuild them. When we do I will report back and let you know what we found. If you work on yours before we do please let us know what you found.

 

[donniej]

It sounds like starvation. Check to make sure that any fuel filters or petcock screens are clear and that your float level is correct.

Running a can of fuel system cleaner through it couldn't hurt either.

 

[SDRider]

You need help from the California Air Resources Board?

 

[TomServo]

It sounds like starvation. Check to make sure that any fuel filters or petcock screens are clear and that your float level is correct.

Running a can of fuel system cleaner through it couldn't hurt either.

I do know the screens are clear and I'm getting good fuel flow to the carbs. Float(s) being stuck/out of whack sounds very likely to me considering the low idle after harder riding and then coming to a stop. The the several seconds of the idle climbing back to normal.

 

[arimichael]

I went cleaned the carbs 3 times! myself. I even had a tech at the shop I used to work at do it a fourth time and synch them. The inlet needles looked pretty good (not worn, no step in the tip, etc.) so I didn't replace them. Same with the diaphragms. And keep in mind, that's a BRAND NEW OEM petcock on it. Old crappy fuel line was replaced too.

 

[donniej]

...considering the low idle after harder riding and then coming to a stop. The the several seconds of the idle climbing back to normal.

Could be... but that's also a sign of runnning rich. While this idle is climbing back up, smell the exhaust for unburnt gas odor. You should also check the plugs, if they're not fouled then you almost definitely have a starvation issue.

If the float bowls have drain screws then open them and see if gas pours out, and can contiune to pour out for several seconds. If it can keep a continuous stream going then the issue is likely with the floats.

 

[Garrett]

Do you still have those turn signal lights? Will they fit an 05 s model?

 

[Toph R]

Check the valves on the bike, I have seen valves on those old bandits do all sorts of funny things to the way the bike idles and drives.