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Check out v twin cafe online motorcycle performance guide. I have a similar setup at stage 3 and drilled small hole (not where needle sits) with 1/8 " bit. My low speed jet is 52 and main is 191. No popping no keihin caugh and mileage is decent. I tried 5 different configurations and purchased all jets online. Fraction of cost versus dealer. You will learn a lot of good info from the website. I rebuild carbs and also change the fuel inlet with brass because the plastic will crack and leak.

 

While the idle mixture screw is commonly only under operation until just off idle to 1/8 throttle, RPM is not as relevant to when that fuel passage is in play. For instance, if you're doing a dyno pull and slam the throttle closed even though the engine is spinning down from 6000 rpm you bet your *** the idle mixture passage is dumping 100% of its fuel because the throttle is closed and the bike is still running.

Sweet spot is 3 turns out on the idle mixture screw at anything less than 2000' elevation. Have you removed the plug from where the idle mixture screw is located?

 

Also, can we get a pic of the main jet if you have one? I'm concerned about that 150 main and I'd like to see if it's a Keihin or DJ jet.

 

Gogobeck, Ive got a similar set up as you, '98 Evo Dyna, SE slip on's with stock headers, Big Sucker intake, Dyna 2000i ignition and EV13 cam. I bought an already modded carb, came with a 48 pilot jet and a 195 main jet, lighter spring and a drilled slide. Thoes jets were way too rich. Ive since backed them down to a 45 pilot and a 185 main and could possibly come down to a 180 main jet. This winter Im going to return to a stock non-drilled slide. Before all these mods I got a steady 48-50mpg. After engine mods (cam, ignition, etc) and extra rich jets I dropped to about 32 mpg. Since backing down to 45/185 jets, Im at about 40 mpg. I get my CV carb parts and jets from CV Performance, never had a problem with their stuff.

 

All you are doing is getting the whole internet to help you guess without an AFR unit installed.
Why do that?

 

Posted how to check the jets in a earlier post, a DJ jet will not fit in a CV emulsion tube and a CV jet won't fit in a DJ emulsion tube, the orifices sizes are the same. A Dynojet jet has DJ stamped in it right before the number.

You are not too rich or the exhaust wouldn't be gurgling or popping which is present right now, a 45 and 185 works well in a early intake timing cam bump like a EV13 . If the slight gurgle doesn't phase you then leave it alone, if it bothers then you know what rpm's the exhaust pop is coming in so you know what circuit is lean. Since you don't have a spot on rpm the pop occurs, making changes needs to have more information, wouldn't touch nothing until you ride it for a while and pin point the problem area.

Many of us tune with equipment and not just guessing, I've road many miles with a Wego live on a modded CV, Mikuni 45 and a R1/Super G, carbs are more of a controlled drip and we seem to over think them thinking the dinosaur technology is a precision measuring devise and learn a lesson.

On your needle question, raising the needle would require lowering the clip, if your taper is aggressive on the needle it may make your situation too rich or maybe just right, you never know, the center notch is a starting point but they make different tapered needles. The needle controls your cruising range afr's and affects mpg so it is a fine line, run my engines rich and not worried about fuel mileage, saving dimes can cost a engine plus you won't have a shotgun go off in the exhaust pipe. Leave it alone and RIDE the bike.

 

 

You are correct BUT even tho the engine isn't loaded requiring fuel, it is on the idle jet and mixture like you said, it is pulling air back thru the exhaust in reversion along with the mid needle is shut off and accell pump is eliminated, we are going to be lean lean pop pop. That is why a carb needs to have fuel carry over and on the rich side to battle this, on EFI you add fuel in the low throttle position and high rpm areas to control decel pop. Reasons for why I say you can drive yourself nuts trying to get a carb to be precision with equipment when it is a prehistoric measuring device alone with no equipment but a carb kicks a$$ on a Evo.