Running rough and backfiring

[Anonymous]

I have a 1982 Gs850Gl that I have just replaced with a more complete Airbox, the new one has the cage, the missing end cap, and the funnal tube that goes up the back of the air box, so air flow has been decreased from what it was, but now the bike runs really rough and back fires constantly, only had it running for less then a minute though.
I think the problem might be my fuel misture screws on top, they may be out of adjustment and in my haynes manual does not give factory settings for the carbs. Any help with wear I might move forward to get this bike running smooth is appreciated!

[redliner1973]

1st off, when the airbox was removed, were different jets installed? If no changes to jetting, you may try counting how many turns the mixture screws are out. usually 2 turns out from bottom will get you into the ballpark. :twisted:

[Anonymous]

Here is what I'm noticing, It is very hard to start, and with the throttle held open a little with the choke fully closed is the only time it seems like it wants to starts. Is this a sign of rich or lean?

[daveo]

sounds rich, especially if the backfire is out the exhaust, your description would lead me to also suggest checking the jetting

[redliner1973]

Did you have 'pods' on it before replacing the airbox? if so, the jets were probably changed to richer ones. If not, start at the mixture screws as posted above. :twisted:

[AOD]

backfiring should only occur if the timing is off or you have the spark plug wires on the wrong plug. double check the plugs then you may want to verify the timing if you can...if it has CDI i dont think you can check it.

~Adam

[Anonymous]

It does have a CDI, I'm not really sure it is a backfiring, it does "POP" though. I have never had pods on it, so I wouldn't think I need to rejet it. Whoever had it before was miccing parts to the airbox and had no cage, so it was letting in a tremendous amount of air. Now that I have it back to original it seems to be running richer but not sure which way to turn the fuel mixture screw to Lean it out a little, I would think tightening it would help, but not sure and it is pretty tough to adjust those little screws. Removing the fuel tank after every quarter turn can be very time consuming, does anyone know what factory settings should be?

[redliner1973]

What i did with mine was to remove the 2 bolts holding the tank, and set a 4x4 block of wood under the rear of the tank. With a small screwdriver I was able to easily turn all 4 adjusting screws on the top front of the carbs while not removing the tank. turn them IN (lean) till they stop (DON'T FORCE THEM!!), and then out (richer) about 1.5 to 2.0 turns and try from there. :twisted:

[AOD]

popping can be a sign of lean...but your spark plugs are the best way to determine how its running. my plugs average a coffee tan color, so i can't complain even with the popping mine does under hard decel.

~Adam

[Anonymous]

It is still real hard to start but runs fine once it gets going, not sure why it is near impossible to start even with choke all the way out?

[Anonymous]

It is still real hard to start but runs fine once it gets going, not sure why it is near impossible to start even with choke all the way out? I should have my carb syncronizer tomorrow, and we'll see what happens after i get that set.