Carb trouble? I think.

[MichaelisEvolving]

My bike is stumbling in between a quarter throttle all the way to a half throttle. Number 1 spark plug is very rich but the other 3 of them are fine. The needle is shimmed all the way up and I've tried adjusting the pilot screw to fully closed and the spark plug is still rich and the bike still stumbles. Someone recommended float height being adjusted but before I take apart my carburetor what else am I missing or is there something else I should do before spending 4 hours in carb work?

[James England]

Have the carbs been cleaned at all?

[cajun31]

from what

you are describing it sounds like you need to go back to the basics of carb cleaning 101. You need to be sure the carbs are thoroughly clean and that the float heights are set properly. From there you can tweak them for the bike...i.e. synchronizing and adjusting the pilot screws. You might also want to go through all your electrical connections on the bike to make sure you are not having any electrical carb problems as well. These carbs can be a bear until you truly get them right and once you have arrived there simple preventative maintenance and proper storing techniques will keep them that way for years to come. If it were my bike acting the way yours is the first step I would take would be to go back through the cleaning process as I have stated. You might also want to check to make sure your float needle assemblies are not leaking... flooding the carbs or simply sticking open. There are several threads in the maintenance section that discuss some of these problems and it would benefit you in doing some reading before you begin. The problem you are describing sounds like dirty jets. By the way does the bike idle ok?

[jetmechmarty]

I agree it's an electrical problem. Since you're in Tampa, I'd be willing to bet you have corroded electrical connections all over that bike. Your kill switch is probably full of rust, and probably the ignition switch too. I think taking the carburetors off right now will be a waste of time.

[CaptonZap]

My bike is stumbling in between a quarter throttle all the way to a half throttle. Number 1 spark plug is very rich but the other 3 of them are fine. The needle is shimmed all the way up and I've tried adjusting the pilot screw to fully closed and the spark plug is still rich and the bike still stumbles. Someone recommended float height being adjusted but before I take apart my carburetor what else am I missing or is there something else I should do before spending 4 hours in carb work?

Do you mean that the needle in #1 is shimmed all the way up? Where are the rest positioned? Raising the needle makes it richer. ?????

CZ

[MichaelisEvolving]

Do you mean that the needle in #1 is shimmed all the way up? Where are the rest positioned? Raising the needle makes it richer. ?????

CZ

Sorry what I mean is the needle goes as far down as it's capable due to the lock washer. It can't become any leaner essentially.

[MichaelisEvolving]

I agree it's an electrical problem. Since you're in Tampa, I'd be willing to bet you have corroded electrical connections all over that bike. Your kill switch is probably full of rust, and probably the ignition switch too. I think taking the carburetors off right now will be a waste of time.

It could be electrical but I redid all the electrical when I got the bike and the electric starter is new cause I installed an arcade switch on a custom plate attached to the bike. I don't have a kill switch because I took it off. But I'm sure there is something somewhere that could be corroded.

[MichaelisEvolving]

you are describing it sounds like you need to go back to the basics of carb cleaning 101. You need to be sure the carbs are thoroughly clean and that the float heights are set properly. From there you can tweak them for the bike...i.e. synchronizing and adjusting the pilot screws. You might also want to go through all your electrical connections on the bike to make sure you are not having any electrical carb problems as well. These carbs can be a bear until you truly get them right and once you have arrived there simple preventative maintenance and proper storing techniques will keep them that way for years to come. If it were my bike acting the way yours is the first step I would take would be to go back through the cleaning process as I have stated. You might also want to check to make sure your float needle assemblies are not leaking... flooding the carbs or simply sticking open. There are several threads in the maintenance section that discuss some of these problems and it would benefit you in doing some reading before you begin. The problem you are describing sounds like dirty jets. By the way does the bike idle ok?

The bike idles very nicely but I think it's very possible that the float may be messed up. My friend whose been helping me suggested that but wanted me to ask on here before we started taking it apart.

[Prisoner6]

It could be electrical but I redid all the electrical when I got the bike and the electric starter is new cause I installed an arcade switch on a custom plate attached to the bike. I don't have a kill switch because I took it off. But I'm sure there is something somewhere that could be corroded.

Hey, Michael -

You say you "redid all the electrical" ... did that include checking for broken pick-up coil wires?

A couple of other things to check for:

1) A cracked/split vacuum advance hose (the one that should be connected to the #2 carb body - and BTW, make sure it is connected to the carb body, NOT the carb boot.

2) A blocked fuel cap vent

One or more of these things could cause the bike to stumble/stutter ... JAT