Author Topic: B4 Carbs (Read 3303 times)

mwelke2005 · « **on:** April 26, 2006, 12:01:37 AM »

I have a 91 bandit 400 that i just bought. Ive run the carbs thru a ultra sonic cleaner and had them balanced. The only problem is that when i try to set the idle under 2K it just slowly dies out. As i ride the idle goes up and i have to keep turning it back down, but then when i stop at a light, it dies. Another thing is that it takes forever for the idle to come back down when you rev it up. on the bikes i've worked on it always comes right back down but this one hangs up there for a bit and comes down very slow. I know that the throttle isnt stuck but have no idea what to do from here.

PitterB4 · « **Reply #1 on:** April 26, 2006, 06:02:50 AM »

Sounds like maybe a vac leak? Did you get the little o-rings back under each cap?

gsxr400 racer · « **Reply #2 on:** April 26, 2006, 10:11:15 PM »

CARB SYNC

PitterB4 · « **Reply #3 on:** April 26, 2006, 10:43:26 PM »

Says he did, Jay...

Quote from: "mwelke2005"

I have a 91 bandit 400 that i just bought. Ive run the carbs thru a ultra sonic cleaner and had them balanced...

I'm not just another pretty face, you know!

tomacGTi · « **Reply #4 on:** April 26, 2006, 10:57:01 PM »

Here's my .02$ from my dicking around with the carbs on my bike....

If the throttle doesn't come back down to idle after a quick rev, chances are it may be set a bit lean. I would reset all of the mixture screws to 2.5 turns and go from there.

Check your choke cable to make sure it's retracting all the way as well. When my cable was binding (more like rusty in the middle and hanging open) it would run a good deal fat all the time and started to foul the plugs. There were times when the bike wouldn't start from cold without full choke and the assistance of starting fluid. With mine, the idle does rise to 1700 after the bike warms up, so I would set it with the bike hot, not when it's cold.

My throttle response after a valve adjust/carb synch was night and day. Even without the valve adjust, when all the carbs were finally synched it was a huge difference. I'd advise taking a look at Factory Pro's CV carb site for more info, it's quite thorough.

-Randy

interfuse · « **Reply #5 on:** April 26, 2006, 11:24:04 PM »

Problem = Running lean at idle. Reason:
a. too much air at idle (intake leak)
b. not enough fuel (restricted or clogged pilots, low float height)

solution =
a. less air
b. more fuel

More info would help... stock bike? after market pipe? K&N filter? jet kit? Mixture screw setting? Needle clip? Modded air box? Float height?

gunter · « **Reply #6 on:** April 29, 2006, 07:42:46 PM »

I agree with tomac- sounds like your idle screws are out of whack.