A good thorough cleaning never hurts as long as you can get it all put back together correctly.  If you use the dip bath method, make sure you remove all the o-rings and rubber parts (diaphragm and TEV diaphragm).

Good diagram of the carb in post #2 —>   http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1098869040

Removing Air/Fuel Mix Screw —>  http://suzukisavage.com/cgi-bin/YaBB.pl?num=1350749896/0

If you decide to clean it or not, you have to get that A/F mix screw back in functional condition.

If you decide to go the Mikuni VM36/38 route, Lancer sells a complete kit.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1338654578

When I had my old S40 with a Mikuni VM36, it was from Murray’s carbs.

His jet set up (tune) is very different than Lancer’s typical recommended set up.  I ended up rejetting using Lancer’s guidance for the main jet and it was much better.  Murray swears by his setup, but the main jet is too lean (#165).  Lancer recommends somewhere between 180-200 depending on exhaust, elevation, etc.  I rejetted to #200 and liked it better.

SurvivingPhilly has a Murray VM36 carb and he also rejetted his with the #200 and liked it better.

Murray can be a crusty old bird when you start asking questions or question his setup.  Defensive you might say.  I probably rubbed him the wrong way too.  He also makes the exposed length of his throttle cables about 1” too long and gets really defensive about that.  He ended up making 3 for me until I got one that was workable (it was the principle of the matter).  He only charged me for 1 (like $15).  That’s a good deal and he custom makes the cables (nice quality).  I was able to modify and shorten the other 2 cables he sent, so I have a couple backups now.

He’s reputable and stands behind his work.  Even if you gotta argue with him a bit.

If you can find a tap the size and thread of the AF screw you might want to chase the threads in the carburetor. If you can't find a Bottom Hole tap, you can cut the taper off of the regular tap. If you can't Find a tap, a bolt with a slot cut into it, with the slot angled such that the deep side of the slot is to the left of the center of the bolt will chase threads. I've got several of those in my collection of taps. The harder the bolt, the better, but the carburetor is soft, so less than Grade 8 would probably be okay.
You can dress up threads on a bolt with a nut strategically sliced through, also.

I rebuilt my S40 (2011) again this week.  STILL will not run without the choke on full.  Driving me nuts!  Petcock replaced, all jets cleaned/replaced, fresh fuel, tried the fuel/air screw from 1.5 to 3 turns.  When I try to ease off the choke, or slightly hit the throttle, it will sputter and die.  I think I might just break down and get a new carb.

So I spoke to Murray and his son-in-law yesterday.  Told him I wanted to get a carb for my S40, but wanted to ask a few questions.  He was pretty rude (my carbs are perfect out of the box, if anyone has a complaint, they don't know what they are doing)--I understand having pride in your product, but before I spend $400, I deserve to be treated with a little courtesy.  Would be curious to hear about other experiences with Murray.

How would I contact Lancer to get the kit?  Can you please help me understand why some recommend the VM36 and others suggest the 38?  THANKS!!  Murray told me the sliding carb is much better than the stock version, do you agree?

 

I’m guessing you meant rebuilt your “carb” and not a complete bike tear down and rebuild. YES-I GOT A KIT ON AMAZON, R157

How long have you had the bike?  TWO MONTHS AND I'VE HAD THIS ISSUE SINCE DAY ONE.

Did it run reasonably well when you got it?  NOT UNLESS I HAD THE CHOKE FULL AND OPEND THE AIR/FUEL SCREW TO ABOUT 4 TURNS

What prompted you to rebuild the carb the 1st time?  TRY TO CORRECT THE PROBLEMS.

What did the bike do after the first rebuild?  EXACT SAME THING.

So you’ve done a 2nd carb rebuild… YES

Where are you getting your carb kits?  AMAZON

What jets do you have installed?  STOCK SIZES, NOT CUSTOMIZATION

Did you clean and/or replace the TEV?  NOT, I CAN'T GET ONE OF THE ****SCREWS OUT AND I STRIPPED IT IN FRUSTRATION--I'M THINKING I SHOULD CUT THE HEAD OFF THE SCREW, CLEAN THE TEV, AND THEN PUT THE COVER BACK ON WITH THE REMAINING TWO SREWS AND SOME LIQUID GASKET?

What’s the process you followed to clean the carb?  Simply squirting things with a can of carb cleaner won’t work.  You gotta get all the gunk out of the tiny air passages.  I USED CARB CLEANER, LONG SKINNY BRUSHES AND BLEW IT ALL OUT WITH COMPRESSED AIR.  VERY HARD TO CLEAN THE PILOT JET, SO I PUT IN A NEW ONE FROM THE KIT.  

Are you sure the diaphragm and slide are in good condition?  YES Simply orienting the diaphragm incorrectly under the dome will cause issues.

Did you check the float valve height?  NO If the float bowl isn’t filling up to the proper level, it will go into fuel starvation mode.

Did you reassemble the needle correctly?  CLEANED AND REUSED THE OLD ONE  That can be a bit tricky.  Are you using the stock white spacer?  Or did you modify it or use thinner spacers (washers)?  Are you using an authentic Mikuni needle or some unmarked needle that came out of a cheap eBay carb kit?

About the only thing good in those cheap carb kits might be the float bowl gasket.  All the other unmarked junk in those kits is a crapshoot.  MOST OF THE ITEMS WERE UNMARKED AND I WAS SUSPICIOUS

Do you have everything buttoned up tight (no air leaks) and the air filter installed?  I HAVE BEEN TESTING IT WITHOUT CONNECTING TO THE AIR BOX.   GOOD-TIGHT CONNECTION TO THE MANIFOLD GASKET.  An air leak at the intake boot or manifold can create an overly rich condition.  It can be something this simple.

We’ll need some background and details to get started.

THANK YOU SO MUCH FOR YOUR HELP!!!  I THINK I SHOULD BUY A KIT THAT HAS THE PROPER MARKINGS ON ALL THE PARTS, CAN YOU PLEASE RECOMMEND ONE?