Mikuni 34s air screws out 4 turns-still a little lean

[mrbridgeport]

Hi guys,

I am running my 81 GS1100e w/ stock carbs (Mikuni 34mm BS34SS). Mac 4 to 1 header with a modified baffle for more airflow out, and some pod filters from APE. A guy had set this up previously a couple years ago and I don't know what jet kit he used.

I synced the carbs yesterday, adjusted the valves, gaped new plugs and am trying to dial this in w/o completely rebuilding the carbs.

Does 4 turns out seem a little to much on the fuel screws? It is still running a little lean at 4 out from the seated position. The air screws are also completely chewed up, nearly stripped on carb 2.

I guess what I am asking is how much is to much on the air screws before changing the main jet setting. I thought the air screws should be at 2 and a half turns out.

I am pretty new to the carb tuning game. Right now it seems to be a little flat (seams lean) between 3,500 and 5,000 rpm. Plugs are almost were they should be color wise, but I'd like to set this up right in the near future. Anyone have some specs to follow for this type of set up?

Thanks in advance.

-joe

 

[gearhead13]

Those are fuel screws, the further turned out the richer it is. You might need to go up one size in pilot jet size. It should have 45's stock, next up is 47.5, which is recommended with pipe/pods.

 

[mrbridgeport]

Thanks Gearhead,

I will pull those and see what number they are. Do any of the other jets need to change for the pod / pipe set up?

-j

 

[Guest]

You need a Dynojet kit with those pods if you want it to run right. (Unless it already has one)
Get some 47.5 pilot jets also.

 

[rapidray]

If it does not have adjustable needles in it yet, I have them if you need. Call me at 714-356-7845 if you ever need help without waiting on an answer from the forum. Ray.

 

[Steve]

Those are fuel screws, the further turned out the richer it is.

Actually, they are mixture screws, but the operation is the same, out for richer PILOT circuit (idle and very low throttle), in for leaner.

The number of turns out on the mixture screws has NOTHING to do with determining when to change your MAIN jets. That will only determine when to change your PILOT FUEL JETS, which, as everyone else has said, are 45, if they are stock. If you need to go larger, just go one size to 47.5 (again, already mentioned).

With a MAC pipe and APE pods, you should probably be 6 to 8 sizes larger on the mains, but that is part of what the Dynojet kit will get you. Sure, you can experiment a bit with different jet sizes and save some money, but what you WON'T get by doing that is the different needles that come with the DJ kit. The taper on them is considerably different than stock, and that is what makes the DJ kit worth the money.

.