replacement carburetor confusion

[kilcal]

Hi all,
I bought a 1993 st1100 a few months back and was told all it needs is a carb adjustment as it would only idle. I was hoping worst case carb cleaning. Upon removing the plenum on top of the carbs one of my diaphragm pistons looked melted. I probably should have stopped there and figured what could cause this before proceeding.But instead I bought another full carb set off another 1993 for under a hundred bucks and started cleaning,rejetting and getting back on. My confusion is that the carbs look identical except my new set does not have the little fuel nipples just above the bowl on each carb and it does not look like they ever had any. I will attach specific pics. Also on carb#4 the pilot adjustment screw is on the inside of the carb as opposed to the outside on the original and on the insidepf the original is a fuel nipple. My question is which is right and what has to be done to the new carbs do they will operate correctly. Thanks any help is appreciated!

 

[kilcal]

Trying to upload pics, all four hoses attach to a plastic circle that all the lines connect to

 

[kilcal]

Melted , Any ideas what would cause this?

 

[kilcal]

The circular plastic piece on the left side with a seperate hose for each carb and the fittings that it attaches to on the carbs are non existent on the replacement. Are these required and what is its purpose?

 

[afrymoyer]

Your bike is an ABS / California emission bike and has all the evaporative emission components..... You purchased from e-bay, 49 state NON-emission carbs. Hence the legitimate factory differences.

You can easily fix your original carbs by purchasing a new diaphragm assy and replacing the burnt one. Service YOUR carbs and re-install. Or use the purchased e-bay carb bank for parts. Diaphragms are the same. I believe the needles are different, so be sure all the slide needles are the same during re-assy.

The original diaphragm slide is burnt from repeated backfire up through the intake. Be sure that your engine is freshly tuned (plugs, filters, fluids, etc) Check for vacuum leaks, especially at that particular cyl that's burnt. I hope your installing new carb mount boots. Also have a look at the valve clearances and adjust if needed.

 

[kilcal]

Thanks Adam, can I use the eBay carbs without the emission equipment instead of fixing the originals. I already cleaned and set up the new ones and would prefer to remove any emission equipment when possible as long as it doesn't interfere with reliability.

 

[afrymoyer]

Yes... You can use those 49 state NON-emission carbs. Remember that you'll have to remove all the plumbing that is used for the evaporative emission system(or plug it all off). You wont loose any reliability. If anything, you'll gain. Less crap in there to go wrong.... Cam timing is slightly lazier on those emission bikes. If you changed over to the #40 pilot's, start off with 1 7/8 turns on the idle mixture screws and go from there.

 

[kilcal]

Great,thanks so much for your advice!

 

[George]

I agree with all Adam's notes. Currently in the throes of a full clean on a set of 93 non-ABS carbs. Soon's this is done and installed, I'll do the same to the set coming off of STick and set'em on the shelf for future use.