Adjustment screw locations

[Guest]

Pardon the noob question but I am trying to locate the air adjustment screw on my BS34 carburetor's. I know where the (pilot) fuel adjustment screw is (on the side under the plug) and I know where the idle speed adjustment is. I have looked through the guides on Basscliff's site but I haven't seen an air adjustment screw. Am I looking for something that doesn't exist?

The carbs were rebuilt by Bill Rea (aka Chef) from this site and even though the PO really made a mess inside them, Bill was able to repair and rejet them. I have the bike running and it idles fine but there is backfire when decelerating and the idle stays high. The pilot screw is set at 2 1/2 turns out.

[Nessism]

The pilot screw is set at 2 1/2 turns out.

This is the only adjustment for mixture.

Did you replace the intake boot O-rings and possibly the boots themselves? Did you vacuum sync the carbs? Is the intake/exhaust stock? If running pods you will have to play with jetting.

[LAB3]

FYI the pilot screws are set at two turns out right from the factory on my bike and it runs quite well at that setting. I'm with Nessism on checking for an air leak, that's probably the best bet as to the backfiring and high idle. On my bike I found it best to have the air box unbolted so it can move freely and make a good snug fit to the carburetors. There are thin rubber sleeves on the inside of the airbox that can slide back and forth to make a good seal to the carbs, I used a pair of hemostats to pull those forward and get a good seal. After you have that done THEN bolt the airbox back down.

[Nessism]

If not done already it's strongly recommended to remove the carb boots, flex them to look for evidence of cracks and general stiffness, and replace the O-rings at minimum and possibly the boots too. Spraying junk on the boots as a way of determining air leaks will only work for large gross leaks, not smaller leaks which can affect the idle.

[VABushPig]

The O-rings and boots are new. It wasn't vacuum synced. I am using K&N pod filters and it has a 2 into 1 Kerker exhaust. Here is what the person that rebuilt the carbs said:

"There is a jet kit installed. Not sure what kit but the jet needles have adjustable notches and the slides were drilled. Since there are no stock jet needles I will use these and hope whoever installed them have the clip on the correct notch. The emulsion tubes have tool marks on them but I will use them. Smooth them out with 4000 grit. They will be fine.

For some reason the main air jet on the #2 carb was blocked off. This would not allow air to flow to pick up fuel from the main jet. Not sure why this was done.
The reason you need a float bowl is because the main jet was destroyed along with the threads. Lucky found one for $25 on eBay. You also need a pilot air jet for #2 since it was also destroyed.
I will use 130 main jets (jetting for pipes/pods) to replace the 115 which is stock. Not sure what size was in there since both were destroyed but got one out clean and tapped the threads.
The float needles were both notched up and would of leaked. I did have two good parts to replace these.
These carbs will be fine just need some attention. They were messed up a bit by a previous owner but can be salvaged."

It appears the PO wasn't quite the mechanic he thought he was.