No ,Ohiomoto you have it backwards , it's a fuel mix screw, the more you open it the more fuel you add to the idle circuit .  we have no air mix screw. If the screw is out 3+ turns it could mean you need to go to the next larger pilot jet , but I would first check to see if the spacer mod was done, and how many #4 steel washers washers were used . (I would think two for his elevation -near sea level) and at least a 150 main jet. ( I know of only one owner running the stock 145 and he's at 6000 ft in the Rockies).

  Liftdt4r , If the PO used the wrong oil and the clutch is slipping it may be that the discs and steels are glazed, soaking them in gas and giving them a light sanding ,allowing them to dry ,and oiling them ,should return them to normal . But I'd try just changing to some good -moly free-oil ,the slipping may stop over time ,if you do a couple of changes over a bit faster intervals ,say 1,000 miles?

Thanks guys, awesome info!!

So, if I'm more than 2.5 turns out on the idle mix screw when tuning the bike I should be going to a LARGER pilot jet, correct? That's what I figured as I believe backing out the screw makes the bike richer.

I'm sure I'll have to pull the carb off and mess around with it some more. I have no clue what the PO did and I doubt he does either. I'm just looking for a starting point and I think 152.5 / 52.5 is it. At least that's what Ryca recommends and that's what it looks like folks are doing here.

I got pretty far rebuilding my carb today. Lots of scrubbing and playing around with stuff. Dropped in a new needle jet and jet needle as well as did the white spacer mod. I am using 3 washers to start. The needle in my rebuild kit had 3 clip positions on it so I used the one closest to stock. The taper of the needle and length look identical.

Also, I got a replacement pilot in my rebuild kit but it looks quite a bit different than the one that came out of my carb. The one that was in my carb is on top and the one from the rebuild kit is on the bottom. I'm not worried about the depth but I am worried about the taper of the needle. The needle on the rebuild one looks much thinner. Any advice on this?

Looks like you got a ''universal'' carb rebuild kit. Fits a little of everything, sort-of, and exactly fits nothing. That screw ain't even close, and if the needle for inside the slide has 3 notches, IT'S WRONG!
Reuse the stock needle, they don't wear out, ever. They can get bent or installed wrong however.

batman wrote on 04/14/19 at 09:42:40:
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I stand corrected then!  If it's a fuel screw, my advise was screwed up.  Sorry Liftd.

Leave the filter in the carb. I clean mine every 20k or so, and they DO catch stuff.

I did almost 7k last August on my Salt Flats trip.
I have had my bike just over 4 years. Rolled over 84k coming home from the west coast (Florida) saturday night. I'm really getting to like this retirement thing! End of the month I'm going to South Carolina for a Roller Derby Tournment, should be 1600 miles in 3 1/2 days. I have done the thousand in one 2 & 1/2 times with this bike. The third time it was only 998 miles.
Living in S. Florida I can ride year-around. And it is 5 hours to the state line whenever I go anywhere. I have always tried to travel on a bike, and now I don't have to worry about work if I want to change my plans while on the road so be it.
I put 140k on my old Yamaha 750 triple, about 240k on my Gold Wing, 78k on my Pacific Coast, and now my aim is 150k on this S-40. should hit 100k by the end of this year.
I have a pin in my leg (old MX injury) but some of my friends think I have a stainless steel backbone.